71M6515H-DB

71M6515H Demo Board User’s Manual 71M6515H Demo Board USER’S MANUAL 12/5/2005 2:06 PM Revision 2.0 TERIDIAN Semiconductor Corporation 6440 Oak Canyon Rd. Irvine, CA 92618-5201 Phone: (714) 508-8800 ▪ Fax: (714) 508-8878 http://www.teridian.com/ meter.support@teridian.com Revision 2.0 1 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual TERIDIAN Semiconductor Corporation makes no warranty for the use of its products, other than expressly contained in the Company’s warranty detailed in the TERIDIAN Semiconductor Corporation standard Terms and Conditions. The company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice and does not make any commitment to update the information contained herein. Revision 2.0 2 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 71M6515H 3-Phase Power Meter AFE IC DEMO BOARD USER’S MANUAL Revision 2.0 3 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual Table of Contents 1 GETTING STARTED .......................................................................................................................................... 7 1.1 General............................................................................................................................................................... 7 1.2 Safety and ESD Notes....................................................................................................................................... 7 1.3 Demo Kit Contents ............................................................................................................................................ 7 1.4 Compatibility Statement ................................................................................................................................... 7 1.5 Suggested Equipment not included ................................................................................................................ 8 1.6 Demo Board Test Setup.................................................................................................................................... 8 1.6.1 Power Supply Setup..................................................................................................................................... 9 1.6.2 Serial Connection Setup ............................................................................................................................ 10 1.7 Preparing the PC ............................................................................................................................................. 10 1.8 Using the Demo Board.................................................................................................................................... 11 1.8.1 Starting up the Demo Board and the GUI Program.................................................................................... 11 1.8.2 Controlling the Demo Board ....................................................................................................................... 11 1.8.3 GUI Window - Overview............................................................................................................................ 12 1.8.4 GUI Window – Display and Control Fields ................................................................................................. 12 1.8.5 GUI Window Control and Display Fields – Detailed Description ................................................................ 14 1.8.6 Adjusting the Kh Factor for the Demo Board.............................................................................................. 24 1.8.7 Adjusting the Demo Boards to Different Current Transformers and Voltage Dividers ................................ 25 1.9 Calibrating the Demo Meter............................................................................................................................ 26 2 APPLICATION INFORMATION........................................................................................................................ 27 2.1 Calibration Procedure..................................................................................................................................... 27 2.1.1 Calibration Systems ................................................................................................................................... 27 2.1.2 Definitions .................................................................................................................................................. 27 2.1.3 Error Sources in a Meter ............................................................................................................................ 28 2.1.4 Calibration with Three Measurements........................................................................................................ 29 2.1.5 Calibration with Five Measurements .......................................................................................................... 30 2.1.6 Calibration for Meters with Rogowski Coil Sensors.................................................................................... 31 2.1.7 Calibration Spreadsheets........................................................................................................................... 32 2.1.8 Compensating for Non-Linearities.............................................................................................................. 33 2.2 Schematic Information.................................................................................................................................... 35 2.2.1 Components for the VFLT Pin.................................................................................................................... 35 2.2.2 Reset Circuit .............................................................................................................................................. 35 2.2.3 Oscillator .................................................................................................................................................... 35 2.3 Testing the Demo Board................................................................................................................................. 37 2.3.1 Testing the Demo Board Using the GUI..................................................................................................... 37 2.3.2 Functional Meter Test ................................................................................................................................ 38 3 HARDWARE DESCRIPTION ........................................................................................................................... 41 3.1 Board Description: Jumpers, Switches and Test Points ............................................................................. 41 3.2 Connector Descriptions.................................................................................................................................. 44 Revision 2.0 4 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 3.2.1 3.2.2 3.2.3 JP6 – SSI Interface .................................................................................................................................... 44 JP18 – External Interface........................................................................................................................... 44 JP21 – Debug Interface ............................................................................................................................. 45 3.3 Board Hardware Specifications ..................................................................................................................... 46 4 APPENDIX........................................................................................................................................................ 47 List of Figures Figure 1-1: TERIDIAN 71M6515H Demo and Debug Boards: Basic Connections......................................................... 8 Figure 1-2: Block diagram for the TERIDIAN 71M6515H Demonstration Meter with Debug Board .............................. 9 Figure 1-3: Control Program Icon................................................................................................................................. 10 Figure 1-4: Host GUI Window w/ Functional Groups (Areas) Marked and Numbered ................................................. 12 Figure 2-1: Phase Angle Definitions............................................................................................................................. 28 Figure 2-2: Watt Meter with Gain and Phase Errors ................................................................................................... 28 Figure 2-3: Calibration Spreadsheet for Three Measurements .................................................................................... 32 Figure 2-4: Calibration Spreadsheet for Five Measurements....................................................................................... 33 Figure 2-5: Non-Linearity Caused by Quantification Noise .......................................................................................... 33 Figure 2-6: Voltage Divider for VFLT ........................................................................................................................... 35 Figure 2-7: External Components for RESETZ ............................................................................................................ 35 Figure 2-8: Oscillator Circuit......................................................................................................................................... 36 Figure 2-9: Typical GUI Window .................................................................................................................................. 37 Figure 2-10: Meter with Calibration System ................................................................................................................. 38 Figure 2-11: Calibration System Screen ...................................................................................................................... 39 Figure 3-1: 71M6515H Demo Board: Connectors, Headers, LEDs, Switches ............................................................. 43 Figure 4-1: TERIDIAN 71M6515H Demo Board: Electrical Schematic 1/3 .................................................................. 48 Figure 4-2: TERIDIAN 71M6515H Demo Board: Electrical Schematic 2/3 .................................................................. 49 Figure 4-3: TERIDIAN 71M6515H Demo Board: Electrical Schematic 3/3 .................................................................. 50 Figure 4-4: TERIDIAN 71M6515H Demo Board: Top View ......................................................................................... 52 Figure 4-5: TERIDIAN 71M6515H Demo Board: Bottom View .................................................................................... 53 Figure 4-6: TERIDIAN 71M6515H Demo Board: Top Signal Layer ............................................................................. 54 Figure 4-7: TERIDIAN 71M6515H Demo Board: Middle Layer 1, Ground Plane. ........................................................ 55 Figure 4-8: TERIDIAN 71M6515H Demo Board: Middle Layer 2, Supply Plane. ......................................................... 56 Figure 4-9: TERIDIAN 71M6515H Demo Board: Bottom Signal Layer ........................................................................ 57 Figure 4-10: Debug Board Schematics ........................................................................................................................ 59 Figure 4-11: Debug Board: Top View........................................................................................................................... 60 Figure 4-12: Debug Board: Bottom View ..................................................................................................................... 60 Figure 4-13: Debug Board: Top Signal Layer............................................................................................................... 61 Figure 4-14: Debug Board: Middle Layer 1, Ground Plane .......................................................................................... 61 Figure 4-15: Debug Board: Middle Layer 2, Supply Plane ........................................................................................... 62 Figure 4-16: Debug Board: Bottom Trace Layer .......................................................................................................... 62 Figure 4-17: TERIDIAN 71M6515H LQFP64: Pinout (top view)................................................................................... 65 Revision 2.0 5 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual List of Tables Table 1-1: Jumper settings on Debug Board................................................................................................................ 10 Table 1-2: Straight cable connections .......................................................................................................................... 10 Table 1-3: Null-modem cable connections ................................................................................................................... 10 Table 3-1: 71M6515H Demo Board Description: 1/3 ................................................................................................... 41 Table 3-2: 71M6515H Demo Board Description: 2/3 ................................................................................................... 42 Table 3-3: 71M6515H Demo Board Description: 3/3 ................................................................................................... 43 Table 3-4: JP6 Pin Description..................................................................................................................................... 44 Table 3-5: JP18 Pin Description (pins 3, 5, 7, 9, and 17 are non-functional) ............................................................... 44 Table 3-6: JP21 Pin Description................................................................................................................................... 45 Table 4-1: 71M6515H Demo Board: Bill of Material..................................................................................................... 51 Table 4-2: Debug Board: Bill of Material ...................................................................................................................... 58 Table 4-3: 71M6515H Pin Description Table 1/2 ......................................................................................................... 63 Table 4-4: 71M6515H Pin Description Table 2/2 ......................................................................................................... 64 Revision 2.0 6 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 1 1 GETTING STARTED 1.1 GENERAL The TERIDIAN Semiconductor Corporation (TSC) 71M6515H Demo Board is a demonstration board for evaluating the 71M6515H IC for 3-phase electronic power metering applications. It incorporates a 71M6515H integrated circuit, peripheral circuitry such an on-board power supply as well as a companion Debug Board that allows a connection to a PC running Windows® 2000/XP through a RS232 port. The demo board allows the evaluation of the 71M6515H power meter controller chip for measurement accuracy and overall system use. A control program running on a Windows 2000/XP compatible PC allows control and monitoring of the 71M6515H IC on an abstract level via a graphical user interface (GUI). 1.2 SAFETY AND ESD NOTES Connecting live voltages to the demo board system will result in potentially hazardous voltages on the demo board. EXTREME CAUTION SHOULD BE TAKEN WHEN HANDLING THE DEMO BOARD ONCE IT IS CONNECTED TO LIVE VOLTAGES! THE DEMO SYSTEM IS ESD SENSITIVE! ESD PRECAUTIONS SHOULD BE TAKEN WHEN HANDLING THE DEMO BOARD! 1.3 DEMO KIT CONTENTS • 71M6515H Demo board containing 71M6515H AFE IC • Debug Board • Two 5VDC/1,000mA universal wall transformer with 2.5mm plug (Switchcraft 712A compatible) • Serial cable, DB9, Male/Female, 2m (Digi-Key AE1020-ND) • CD-ROM containing documentation (data sheet, board schematics, BOM, layout), PC executable program (GUI), and calibration spreadsheet Note: The media CD-ROM contains a file named readme.txt that specifies all files found on the media and their purpose. 1.4 COMPATIBILITY STATEMENT This manual is compatible with REV1.1 (October 14, 2005) of the Control Program (GUI) and with 71M6515H code revision 1.1 (October 14, 2005). Revision 2.0 7 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 1.5 SUGGESTED EQUIPMENT NOT INCLUDED PC w/ MS-Windows versions XT, ME, or 2000, equipped with RS232 port (COM port) via DB9 connector 1.6 DEMO BOARD TEST SETUP Figure 1-1 shows the basic connections of the Demo Board plus Debug Board with the external equipment. Power supply for Demo Board Country-specific plug adapters (US, Europe, UK, Australia) Demo Board Power supply for Debug Board Debug Board Serial connection to PC Figure 1-1: TERIDIAN 71M6515H Demo and Debug Boards: Basic Connections The 71M6515H demo board system is shown in Figure 1-2. It consists of a stand-alone rectangular meter Demo Board and an optional Debug Board (most Debug Boards are partially assembled and have less components than shown in Figure 1-2). The Demo Board contains all circuits necessary for operation as a meter front end, calibration LEDs, and power supply. The Debug Board is optically isolated from the meter and interfaces to a PC through a 9 pin serial port. For serial communication between the PC and the TERIDIAN 71M6515H, the Debug Board needs to be plugged with its connector J3 into connector JP21 of the Demo Board. Connections to the external signals to be measured, i.e. scaled AC voltages and current signals derived from shunt resistors or current transformers, are provided on the rear side of the demo board. Note: It is recommended to set up the demo board with no live AC voltage connected, and to connect live AC voltages only after the user is familiar with the demo system. Revision 2.0 8 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual DEMONSTRATION METER External Current Transformers IA JP26 IB JP27 IC IA D6 JP30 71M6515H Single-Chip Meter AFE V3P3 D5 WPULSE V3P3 RPULSE IB PULSE3 IC PULSE4 JP29 External Interface Connector JP18 WPULSE RPULSE JP28 V3P3 VC VB VA DIO 0...8 JP24 JP23 TX RX JP22 VA VB VC JP1 V3P3 JP25 SSI Connector SSI Signals JP6 3.3V NEUTRAL GND 5V DC DEBUG BOARD (OPTIONAL) GND S1 TX OPTO RX JP9 JP32 JP31 DB9 to PC COM Port RS-232 INTERFACE OPTO UARTCSZ OPTIONAL RTM INTERFACE OPTO SUPPLY TMUXOUT OPTO BAUDRATE CKTEST OPTO FPGA V5_DBG 5V DC PULSE_INIT OPTO SUPPLY V5_NI GND_DBG GND JP21 Figure 1-2: Block diagram for the TERIDIAN 71M6515H Demonstration Meter with Debug Board Note: All input signals are referenced to the V3P3 (3.3V power supply to the chip). 1.6.1 POWER SUPPLY SETUP There are several choices for meter power supply: • Internal (using phase A of the AC line voltage). The internal power supply is only suitable when phase A exceeds 220V RMS. • External 5VDC connector (J1) on the Demo Board and external 5VDC connector (J1) on the Debug Board. The power supply jumper JP1 must be consistent with the power supply choice. JP1 disconnects phase A from the power supply. This jumper should usually be left in place. The internal supply is not strong enough to power the Debug Board. Thus, the external power supply should always be used for the Debug Board, regardless whether the meter is powered by its internal supply or through an external supply. Revision 2.0 9 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 1.6.2 SERIAL CONNECTION SETUP For connection of the DB9 serial port to a PC, either a straight or a so-called “null-modem” cable may be used. JP1 and JP2 are plugged in for the straight cable, and JP3/JP4 are empty. The jumper configuration is reversed for the null-modem cable, as shown in Table 1-1. Configuration JP1 JP2 JP3 JP4 Straight Cable installed installed -- -- -- -- installed installed Null-Modem Cable Table 1-1: Jumper settings on Debug Board JP1 through JP4 can also be used to alter the connection when the PC is not configured as a DCE device. Table 1-2 shows the connections necessary for the straight DB9 cable and the pin definitions. PC Pin Function Demo Board Pin 2 TX 2 3 RX 3 5 Signal Ground 5 Table 1-2: Straight cable connections Table 1-3 shows the connections necessary for the null-modem DB9 cable and the pin definitions. PC Pin Function Demo Board Pin 2 TX 3 3 RX 2 5 Signal Ground 5 Table 1-3: Null-modem cable connections 1.7 PREPARING THE PC The Control Program PMtest.exe must be copied from the CD-ROM to a directory on the host PC. The program can then be started directly by double-clicking on the PMTest.exe icon (see Figure 1-3). PMTest.exe Figure 1-3: Control Program Icon PMTest.exe can work in two baud rates and on any COM port. To configure PMTest.exe for the desired operation mode, the original PMTest.exe file is copied to or renamed to a file with a name of the form: PMTestxxxCy.exe If xxx = 192, the program will operate at 19.2kb/s, if xxx = 384, the program will operate at 38.4kb/s (UART speed when communicating with the 71M6515H). The number substituted for y states the COM port number that the program is using for communicating with the host. Example: When named PMTest192C2.exe, the program will operate with 19.2kb/s via COM port 2. Revision 2.0 10 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual Note: For smooth operation of the PMTest program it is important to observe the following rules: • It is important to exit all programs that access COM port 1 before PMTEST.exe is started. • Make sure all applicable updates to the Windows ® operating system are installed before running the application. • PMTest.exe will not run on Windows® 98 or older operating systems. Real-time performance can be affected by processor-intense operations of the PC, such as starting new applications, loading files into applications, or ending applications. Such operations have to be avoided to ensure uninterrupted communication between PC and the 6515H Demo Board. Do not press the ALT key on the keyboard! 1.8 USING THE DEMO BOARD The 71M6515H Demo Board is a ready-to-use meter with a preprogrammed scaling factor Kh of 3.2 Wh/pulse. In order to be used with a calibrated load or a meter calibration system, the board should be connected to the AC power source using the spade terminals on the bottom of the board. The current transformers should be connected to the dual-pin headers on the bottom of the board. For the Kh to be adjusted properly, current transformers with 2,000:1 winding ratio must be used. 1.8.1 STARTING UP THE DEMO BOARD AND THE GUI PROGRAM In order to control and monitor the Demo Board, the connections specified in section 1.6 have to be established. The sequence of actions when powering up the Demo Board is as follows: 1. 2. 3. 4. 5. 6. Power up the Demo Board Start the GUI Control Program PMTest.exe. Check for communication between the GUI Control Program and the 71M6515H. Communication is established when the green “LED” indicator labeled 1SEC on the GUI screen flashes red every second. Initialize the 71M6515H to match the desired application and measurement parameters. Establish the CE image, calibration factors, pulse parameters, nominal temperature, IMAX/VMAX using the commands and fields described in 1.8.2. Establish the desired configuration using the bits of the CONFIG register (field 16 in the GUI window), but do not enable the CE. Enable the CE by clicking the square button next to “CE_ENABLE”. Once, voltage is applied and load current is flowing, the red LED D5 will flash each time an energy sum of 3.2 Wh is collected. Similarly, the red LED D6 will flash each time a reactive energy sum of 3.2 VARh is collected. 1.8.2 CONTROLLING THE DEMO BOARD Upon starting the PMTEST.exe application, the graphical user interface (GUI) of the demo application shown in Figure 1-4 will be displayed on the screen. The gray boxes are the meter outputs and the white boxes contain host, i.e. user, inputs. It is important to enable the computation engine (CE) in order to see activity in the GUI window. You can check the computation engine (CE) status by verifying the status of the button on the left of CE_ENABLE in the “Config” block of the GUI. It should display a “1”, as shown in Figure 1-4. If not, the CE can be enabled by clicking the “0” button to the left of the “CE_ENABLE” text using the left mouse button. Upon clicking, the “0” will toggle to a “1”, and the green and red indicator lights underneath the “Status/Mask” text will start blinking. Revision 2.0 11 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 1.8.3 GUI WINDOW - OVERVIEW 5 1 7 6 8 3 2 9 17 16 12 11 10 13 18 14 19 4 15 20 Figure 1-4: Host GUI Window w/ Functional Groups (Areas) Marked and Numbered 1.8.4 GUI WINDOW – DISPLAY AND CONTROL FIELDS The PMTEST (GUI) window, as shown in Figure 1-4, contains a number of major blocks or areas (Pulse Source Select, Config, Status/Mask, Calibration Constants, Temperature Compensation, Real-Time Monitor, Digital I/O, Thresholds and Operating Time). These major blocks (labeled 1 through 12 in Figure 1-4) group the functionally related buttons and fields together. The elements of the GUI are as follows: • Rectangular buttons: Buttons that can be clicked by the user to initiate an action. • Square buttons: Buttons that can be clicked by the user to initiate an action. The square buttons have a single digit showing the current state of the signal. A “1” is on and a “0” is off. • Entry fields: White rectangular fields that can be edited by the user. The delete key plus the number and cursor keys work in this type of field. Revision 2.0 12 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual • Display fields: Gray rectangular fields that indicate settings, measurements etc. of the 6515H chip. These fields cannot be edited by the user. • List fields: Entry fields that allow selection from the pre-determined list of choices once the downpointing arrow is pressed (“pull-down” menus). • Indicator lights: Red and green activity indicators underneath the “Status/Mask” label. Green lights mean no activity. Red lights mean that the corresponding bit in the STATUS mask is set, i.e. the condition is true. With an input signal (phase A, B, C voltage) present, the F0 light will be on indicating that the square wave following the input signal is being generated. The light at “1SEC” will blink red every second. Other lights will stay green until the corresponding condition is true, e.g. when the input signal meets a sag or over-voltage threshold. A summary of all of the GUI window areas follows on the next pages. Revision 2.0 13 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 1.8.5 GUI WINDOW CONTROL AND DISPLAY FIELDS – DETAILED DESCRIPTION Energy, Voltage/Current and Phase Area (1): This area is in the upper left corner of the GUI window and contains a number of display fields arranged in columns. Phase A is the left column, phase B is the center column and phase C is the right column. Next to the display fields in this area, there are a list field and a rectangular button controlling basic functions of the Energy, Voltage/Current and Phase Area: GUI Element (Label) Element Type Function Accumulated energy, Instantaneous energy List field This control toggles the display of the Wh, VARh and VAh fields from total accumulated energy to instantaneous energy, i.e. energy per accumulation interval CLR ACCUM Rectangular button Resets the accumulators for Wh, VARh and VAh to zero. It also resets the “Main Edge” counters in the Status/Mask area and the pulse counters. The function of the display fields depends on the selected mode, accumulated or instantaneous energy: GUI Element (Label) Function – Accumulated Energy Selected Function – Instantaneous Energy Selected Wh These fields display the accumulated energy (real power x time) for each phase. These fields display the energy (real power x time) collected during the last accumulation interval for each phase. VARh These fields display the accumulated reactive energy (reactive power x time) for each phase. These fields display the reactive energy (reactive power x time) for each phase. VAh These fields display the accumulated apparent energy (apparent power x time) for each phase. These fields display the accumulated apparent energy (apparent power x time) collected during the last accumulation interval for each phase. Vrms These fields display the momentary voltages (RMS) for each phase. Irms These fields display the momentary currents (RMS) for each phase. Iphase These fields display the momentary phase angles of the currents for each phase. VPhase angle These fields display the momentary phase angles between the phases A and B (underneath “--- AB ---“) and B and C (underneath “---BC---“). Gain Adjust This field displays the current value of the gain adjusted by the temperature compensation mechanism. It is functionally associated with the fields in area 10. When no compensation is active, or the temperature deviation is minimal, the default value of 16384 will be displayed. Revision 2.0 14 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual Calibration Constants Area (2): This area is on the left side of the GUI window and contains three entry fields for each phase. The function depends on the selected CE image (CT/Shunt or Rogowski sensor): GUI Element (Label) Function (CT/Shunt) Calibrate IA Calibration constant for phase A current (default = 16384) Function (Rogowski Sensor) Calibrate VA Calibration constant for phase A voltage (default = 16384) Calibrate IB Calibration constant for phase B current (default = 16384) Calibrate VB Calibration constant for phase B voltage (default = 16384) Calibrate IC Calibration constant for phase C current (default = 16384) Calibrate VC Calibration constant for phase C voltage (default = 16384) Phase Adjust A Calibration constant for phase A current angle (default = 0) Calibration constant for phase A current angle (default = -3973) Phase Adjust B Calibration constant for phase B current angle (default = 0) Calibration constant for phase B current angle (default = -3973) Phase Adjust C Calibration constant for phase C current angle (default = 0) Calibration constant for phase C current angle (default = -3973) During calibration (see section 2.1), the values of the calibration coefficients obtained with the calibration formulae should be entered in these fields. Temperature Compensation Area (3): This area consists of a vertical column of entry and display fields to the right of the Calibration Constants area. The Gain Adjust field from area 1 functionally belongs in the Temperature Compensation area. GUI Element (Label) Element Type Default Raw Display field -- Raw temperature (chip substrate temperature) Delta T Display field -- Difference between raw and nominal (calibration) temperature Nominal Entry field 0 The raw temperature should be entered here during calibration Y Cal deg 0 Entry field 0 The constant correction coefficient for the RTC can be entered here if RTC compensation is required. Y Cal deg 1 Entry field 0 The linear correction coefficient for the RTC can be entered here if RTC compensation is required. Y Cal deg 2 Entry field 0 The quadratic correction coefficient for the RTC can be entered here if RTC compensation is required. Function PPM/C Entry field 0 The linear compensation coefficient of gain over temperature is entered here automatically as soon as a temperature value is entered in the “Nominal” field. Values determined by the host may be entered here if the DEFAULT PPM bit in the Configuration area is set to 0. PPM/C2 Entry field 0 The quadratic compensation coefficient of gain over temperature is entered here. See the PPM/C field for details. DEG SCALE Entry field 22721 Scaling factor for the calculation of temperature. The default value for DEG SCALE (22721) should not be changed. TEMP_X = DEGSCALE * 2-22 * (TEMP_RAW - TEMP_NOM) Revision 2.0 15 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual Rogowski Calibration Area (4): This area consists of two vertical columns of entry fields in the lower left side of the window. The coefficients are only active when the Rogowski image is selected for the CE. GUI Element (Label) Default VFeedA Watt 0 Calibration coefficient for phase A voltage feed through (default = 0) VFeedB Watt 0 Calibration coefficient for phase B voltage feed through (default = 0) VFeedC Watt 0 Calibration coefficient for phase C voltage feed through (default = 0) VFeed A I 0 Not implemented VFeed B I 0 Not implemented VFeed C I 0 Not implemented Function Pulse Source Selection Area (5): This area consists of four list fields to the right of the Energy, Voltage/Current and Phase area. The entries determine the configuration and settings of the two pulse outputs used for four-quadrant metering. GUI Element (Label) Default Function Pulse1 Source Wh This list field allows selection of internal, external, or one of 35 postprocessed parameters as the source for the PULSEW output. Pulse2 Source VARh This list field allows selection of internal, external, or one of 35 postprocessed parameters as the source for the PULSER output. Pulse3 Source Wh This list field allows selection of either an external (host) input or one of 35 post-processed parameters as the source for the PULSE3 output. The selection “none” is also available. When “none” is selected, the pulse output is disabled. Pulse4 Source VARh This list field allows selection of either an external (host) input or one of 35 post-processed parameters as the source for the PULSE4 output. The selection “none” is also available. When “none” is selected, the pulse output is disabled. When external source is selected for any pulse generator, the missing pulse flags (PULSE1, PULSE2, PULSE3, PULSE4) will be active for each accumulation interval for which the host does not provide an input. Pulse Count Area (6): This area consists of a vertical column of display fields underneath the Pulse Source area. GUI Element (Label) Default PULSE1_Cnt 0 This field displays the count of pulses generated on the PULSEW output. PULSE2_Cnt 0 This field displays the count of pulses generated on the PULSER output. Function PULSE3_Cnt 0 This field displays the count of pulses generated on the PULSE3 output. PULSE4_Cnt 0 This field displays the pulse count of pulses generated on the PULSE4. Pressing the CLR ACCUM button in area 1 will reset the pulse counts to zero. Revision 2.0 16 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual External Pulse Control Area (7): This area consists of a vertical column of combined display/entry fields to the right of the Pulse Count area. A field can be made and entry field by selecting “External” for the corresponding pulse source in the Pulse Source Selection area. In all other selections the fields are display fields. When the corresponding Pulse Source selection in the Pulse Source Selection area is “External”, values can be entered in the External Pulse Control fields to simulate pulse control by the host. A new value must be entered in each new accumulation interval. The displayed values return to zero as soon as the next accumulation interval starts and no new values are supplied by the host. If no values are supplied by the host, the associated flags in the STATUS register (see STATUS/MASK area) will be set. If very large numbers are entered, the pulses may be generated over several accumulation intervals. When the corresponding Pulse Source selection in the Pulse Source Selection area is “Internal” or postprocessed values, the display fields of the External Pulse Control area contain input values N that correspond to the pulse rate “f” per the equation: f = WRATE * X * N * 35.82*10-12 In other words, the ADC count corresponding to the applied voltages at the Vn and In pins (VA/IA, VB/IB, VC/IC) will be displayed. GUI Element (Label) Default Function Pulse1 0 Host-provided pulse count for the PULSEW output. Pulse2 0 Host-provided pulse count for the PULSER output. Pulse3 0 Host-provided pulse count for the PULSE3 output. Pulse4 0 Host-provided pulse count for the PULS4W output. Pulse Width and Pulse Rate Control Area (8): This area consists of two entry fields to the right of the Temperature Compensation area. GUI Element (Label) WRATE Default 683 Function This field, together with SUM_CYCLES, VMAX, IMAX and In8 determines the Kh factor of the chip as follows: Kh = VMAX IMAX In8 1.5757 Wh / Pulse SUM _ CYCLES WRATE X X is determined by the two fields PULSE_SLOW and PULSE_FAST in the Configuration area. Pulse Width 6.68ms This field determines the pulse width in ms. Revision 2.0 17 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual System Constants Area (9): This area consists of two entry fields to the right of the Temperature Compensation area. Entries in these fields determine the system parameters of the Demo Board. GUI Element (Label) Default Function IMAX 208A IMAX is the RMS meter current that results in 250mV peak signal at the ADC input. This variable reflects the scaling implemented by the voltage sensing resistors of the Demo Board. Note: When using shunt resistors as current sensors, IMAX must be calculated as (Vppmax = 250mV): IMAX = VMAX 600V V pp max Rsh ⋅ 2 VMAX is the RMS meter voltage that results in 250mV peak signal at the ADC input. This variable reflects the design of the current sensing circuitry of the Demo Board, assuming a 2000:1 current transformer. Warning Thresholds Area (10): This area consists of seven entry fields to the right of the Temperature Compensation area. GUI Element (Label) Creep Default 27000 Function Determines the creep threshold. For each phase, if WSUM_X and VARSUM_X of that phase are less than the value in the CREEP field, the contents of I2h, Wh, and VARh for that phase will be set to zero for the whole accumulation interval. If all phases are below the creep threshold, the CREEP bit in the status word is set. The default value is 6000. Vrms Peak 733.2 Threshold for over-voltage alarms, measured in Vrms. Irms Peak 254.2 Threshold for over-current alarms, measured in Arms. Sag (Vpk) 79.9 Determines the voltage sag threshold. The peak voltage must exceed the voltage entered in this field at least once each SAG_CNT samples in order to prevent a sag warning. Values can be entered directly in Volts. The GUI will round the entered value to the next possible value that can be represented with the resolution used for this parameter. 80 Determines the sag alarm setting. Sag must persist SAG_CNT*397µs before the sag alarm is generated. Allowed range is 1 to (215-1). Default is 80 (31.7ms). SagCnt Starting V 39.974 Determines the voltage below which the calculation of frequency, zero crossings and voltage phase is suppressed. Starting I 0.048 Determines the current below which the calculation of current-related values is suppressed. Revision 2.0 18 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual Real-Time Monitor Area (11): This area consists of four entry fields to the right of the System Constants area. The entries determine any four CE data memory locations to be monitored. The RTM_ENABLE square button in the Configuration area has to be in the “1” position for the RTM to be active. GUI Element (Label) Default Function RTM0 0x00 First CE data memory location to be monitored. RTM1 0x00 Second CE data memory location to be monitored. RTM2 0x00 Third CE data memory location to be monitored. RTM3 0x00 Fourth CE data memory location to be monitored. Note: Using the RTM interface requires special external hardware. Contact TERIDIAN for details. QUANT Area (12): This area consists of three entry fields that can be used to eliminate non-linearity at low currents caused by truncation noise. The parameters entered here are closely related to the calibration parameters. GUI Element (Label) Default Function Watt 0 Noise compensation factor for the Watt calculation VAR 0 Noise compensation factor for the VAR calculation I 0 Noise compensation factor for the current calculation Multi-Purpose Area (13): This area consists of two list fields and three rectangular buttons. GUI Element (Label) Element Type Function SCALED/RAW List field This list field toggles the display of display and entry fields between scaled (displayed values scaled using IMAX and VMAX) and raw data (raw counts from 6515H) mode. In scaled mode, values for voltage, current, and energy will be displayed as V, A, Wh, VARh etc. In raw mode, the values will appear in the internal format of the 71M6515H chip. STANDARD/ HEX List field This list field toggles the values shown in display and entry fields between standard (decimal) and hexadecimal mode. Refresh Rectangular button Pressing this button forces the GUI to transmit any changes made in entry or list fields to the 71M6515H chip. Apply Rectangular button Placing the cursor into another entry field will have the same effect as the Refresh button. Pressing this button will apply a change made in an entry field. CLEAR Rectangular button Pressing this button will clear the contents of the Status Window. Revision 2.0 19 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual Digital I/O Area (14): This area consists of three entry fields below the Real-Time Monitor area. The entries determine the configuration and settings of the eight DIO pins (D0 to D7). GUI Element (Label) Default Function Values 0x00 The hexadecimal number entered here defines the pattern that is applied to the I/O pins. Interrupts 0x00 The hexadecimal pattern entered in this field determines whether a DEDGE interrupt is generated upon a bit changing its status. A 1 means that the corresponding DIO pin generates an interrupt. DEDGE interrupts are only generated for DIO pins that are configured as inputs. Direction 0xFF The hexadecimal number entered here defines whether I/O pins are inputs (0) or outputs (1). A signal transition on an input pin will generate a DEDGE interrupt only once. This interrupt will not be synchronized with the accumulation interval or the 1-sec interrupt. Several transitions per accumulation interval are possible. With every signal transition on a DIO pin, the message “Some Dn pin values have changed!” will be displayed in the Status Window. Status Window Area (15): This is the white, rectangular window at the bottom center of the GUI display. Activities of the PMtest.exe GUI Control program, error messages etc. are listed here. If more events occur than can be displayed in the lines of this window, the display will scroll. Events and messages that occurred in the past will then be displayed by scrolling the window using the scroll arrows to the right of it. When the rectangular CLEAR button above the Status Window is pressed, the messages displayed in the Status Window are deleted. Revision 2.0 20 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual Configuration Area (16): This area labeled “Config” consists of several square buttons, entry fields and list fields located in a column to the left of the Status/Mask area. Combinations of square buttons are mirrored as list fields. This means the same function can be controlled by either pressing the square buttons or by selecting a setting from the corresponding list field. GUI Element (Label) Element Type VA Square button and List field 0 Selects the method for calculating VAh. If 0 is selected, the VAh is computed from VRMS*IRMS, if 1 is selected, VAh is 2 2 computed as the square root of Wh + VARh RTM_ENABLE Square button 0 Enables/disables the Real-Time Monitor. CE_ENABLE must be “1”. CE_ENABLE Square button 0 Enables/disables the CE. EQU 3 Square buttons and Entry field 101 (5) SUM_CYCLES 6 Square buttons and Entry field 111100 (60) CKOUT_DSB Square button 1 Disables the CKOUT pin of the target chip when set to “1”. ADC_DIS Square button 0 The ADC in the 6515H can be disabled by selecting “1” with this button. This setting can be used for saving power on the target chip. TMUX 3 Square buttons and List field 0 (GND) The value for TMUX determines the source selected for the TMUX output pin on the 71M6515H. The value can be selected with the three buttons. Freq Source 2 Square buttons and Entry field 0/0 (A) Hz Display field -- The measured frequency of the phase determined by the “Freq Source” field is displayed here. CE_ONLY Square button 0 The CE only operation mode can be selected by setting this square button to “1”. Omits internal calculation of IPHASE, IRMS, VAH, and VRMS. This feature permits smaller accumulation intervals (SUM_CYCLES < 15). IMAGE 6 Square buttons and Entry field 00 (CT, shunt) The CE mode to be used (standard or Rogowski) can be selected with the two buttons as a binary word. IMAGE cannot be selected while the CE is running. To change the setting, follow this sequence: 1) Disable the CE. 2) Reset the 6515H. 3) Select the new image. 4) Enable the CE. RESET Square button and Rectangular button 0 The 6515H chip can be reset by selecting “1” with this button. Default Function The equation to be used by the CE can be selected with the three buttons as a binary word. The value for SUM_CYCLES can be selected with the six buttons as a binary word. The length of an accumulation cycle is t = SUM_CYCLES * 16.66ms. SUM_CYCLES should be > 15, unless VA = 0 or CE_ONLY = 1. The phase to be used for measuring the signal frequency can be selected with the two buttons as a binary word. Revision 2.0 21 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual GUI Element (Label) Element Type PULSE_SLOW Square button 1 This button, in conjunction with PULSE_FAST and WRATE (in the Pulse Source area), selects the X factor for the pulse generation rate. PULSE_FAST Square button 1 This button, in conjunction with PULSE_SLOW, selects the X factor for the pulse generation rate (see WRATE field). Default Function X 1.5*22 = 6 1.5*29 = 96 1.5*2-4 = 0.09375 1.5 PULSE_SLOW 0 0 1 1 PULSE_FAST 0 1 0 1 IA_8x Square button 0 Additional ADC gain of 8x can be selected for phase A by selecting “1”. IB_8x Square button 0 Additional ADC gain of 8x can be selected for phase B by selecting “1”. IC_8x Square button 0 Additional ADC gain of 8x can be selected for phase C by selecting “1”. DEFAULT PPM Square button 0 This button enables temperature compensation by the host. If the bit associated with DEFAULT PPM is 0, the 71M6515H internally controls the temperature compensation based on the stored VREF characterization values. When DEFAULT PPM is 0, the host may write values into the PPMC and PPMC2 fields to influence temperature compensation. When DEFAULT PPM is toggled back to 0 after the host had written values to the PPMC and PPMC2 fields, these fields will go back to displaying the original internal values. Status Word and Status Mask Area (17): This area consists of 18 square buttons and indicator lights towards the right edge of the GUI window. The bits of the STATUS word are displayed in the indicator lights right next to the square buttons. A green light indicates no activity, a red light indicates that the corresponding bit is set. Individual bits of the STATUS word can be made to generate interrupts. When the square button right next to the status bit is pressed (1), the corresponding bit, when active, will generate an interrupt on the IRQZ output pin. Activity on the IRQZ output pin is indicated with the green LED D8 on the Demo Board. Revision 2.0 22 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual GUI Element (Label) Default Function BOOTUP 1 BOOTUP bit. SAG A 0 sag A bit for phase A. SAG B 0 sag B bit for phase B. SAG C 0 sag C bit for phase C. F0 0 F0 (fundamental of the input signal) bit. MAXV 0 Vpeak bit. MAXI 0 Ipeak bit. 1SEC 0 1-second bit. VXEDGE 0 VXEDGE bit (change in the state of the VX comparator). DEDGE 0 DEDGE bit (change in the state of any selected DIO). XOFV 0 XOVF bit (host has failed to read at least one energy output value). READY 0 READY bit (fresh output values are available). CREEPA 0 Creep bit for phase A. CREEPB 0 Creep bit for phase B. CREEPC 0 Creep bit for phase C. IGNORED 0 Command ignored by the 71M6515H PULSE1 0 PULSEW_ERR bit (missing host data when in external mode). PULSE2 0 PULSER_ERR bi (missing host data when in external mode). PULSE3 0 PULSE3_ERR bit (missing host data when in external mode). PULSE4 0 PULSE4_ERR bit (missing host data when in external mode). Main Edge Area (18): This area consists of two display fields below the Status Word area. GUI Element (Label) Default Function Main Edge COUNT 0 This field displays the number of zero crossings encountered in the last accumulation interval. Main Edge TOTAL 0 This field displays the total number of zero crossings counted since the last reset. The value is reset to zero when the CLR ACCUM button in the Energy, Voltage/Current and Phase Area is pressed. Revision 2.0 23 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual Operating Time/RTC Area (19): This area consists of three display fields and two rectangular buttons, all located towards the lower right edge of the GUI window. GUI Element (Label) Element Type Function Operating time Display field Displays the total operating time of the 6515H chip, measured in 0.01 hours. Real Time Clock Display field Displays the date of year according to the RTC in the 6515H chip. Real Time Clock Display field Displays the time of day according to the RTC in the 6515H chip. Set RTC Rectangular button Pressing this button synchronizes the RTC of the 6515H chip with the clock of the host PC. EXIT Rectangular button Pressing this button will terminate the GUI control program. Chip Version Area (20): This area consists of only one display field. 1.8.6 GUI Element (Label) Function Chip Version This field displays the type and version of the 6515H chip, e.g. 6515HB03. ADJUSTING THE KH FACTOR FOR THE DEMO BOARD The Kh factor (i.e. energy per pulse) is determined by the following equation: Kh = VMAX IMAX In8 1.5757 Wh / Pulse SUM _ CYCLES WRATE X Where: VMAX: The RMS voltage value that corresponds to the 250mV maximum input signal to the IC (default = 600V). IMAX The RMS current value that corresponds to the 250mV maximum input signal to the IC (default = 208A). SUM_CYCLES The value controlling the length of the accumulation cycle, as determined by bits 813 in the CONFIG register (default = 60). The length of an accumulation cycle is t = SUM_CYCLES * 16.66ms. WRATE The value in the pulse rate control register WRATE, (default = 683). X The pulse rate acceleration factor, determined by bits 25 (PULSE_FAST) and 26 (PULSE_SLOW) in the CONFIG register (default = 1.5). Almost any desired Kh factor can be selected for the Demo Board by resolving the formula for WRATE. Revision 2.0 24 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 1.8.7 ADJUSTING THE DEMO BOARDS TO DIFFERENT CURRENT TRANSFORMERS AND VOLTAGE DIVIDERS The Demo Board is prepared for use with 2000:1 current transformers (CTs). This means that for the unmodified Demo Board, 208A on the primary side at 2000:1 ratio result in 104mA on the secondary side, causing 177mV at the 1.7Ω resistor pairs R24/R25, R36/R37, R56/R57 (2 x 3.4Ω in parallel). In general, when IMAX is applied to the primary side of the CT, the voltage Vin at the IA or IB input of the 71M6515H IC is determined by the following formula: Vin = R ⋅ I = R ⋅ IMAX N where N = transformer winding ratio, R = resistor on the secondary side If, for example, IMAX = 208A are applied to a CT with a 2500:1 ratio, only 83.2mA will be generated on the secondary side, causing only 141mV The steps required to adapt a 71M6515H Demo Board to a transformer with a winding ratio of 2500:1 are outlined below: 1) 2) 3) The formula 177mV R x = IMAX N is applied to calculate the new resistor Rx. We calculate Rx to 2.115Ω Changing the resistors R24/R25, R106/R107 to a combined resistance of 2.115Ω (for each pair) will cause the desired voltage drop of 177mV appearing at the IA, or IB inputs of the 71M6515H IC. WRATE should be adjusted to achieve the desired Kh factor, as described in section 1.8.6. Simply scaling IMAX is not recommended, since peak voltages at the 71M6515H inputs should always be in the range of 0 through ±250mV (equivalent to 177mV rms). If a CT with a much lower winding ratio than 1:2,000 is used, higher secondary currents will result, causing excessive voltages at the 71M6515H inputs. Conversely, CTs with much higher ratio will tend to decrease the useable signal voltage range at the 71M6515H inputs and may thus decrease resolution. The 71M6515H Demo Board comes equipped with its own network of resistor dividers for voltage measurement mounted on the PCB. The resistor values (for the 4-layer Demo Board) are 2.5477MΩ (R15R21, R26-R31 combined) and 750Ω (R32), resulting in a ratio of 1:3,393.933. This means that VMAX equals 176.78mV*3,393.933 = 600V. A large value for VMAX has been selected in order to have headroom for over-voltages. This choice need not be of concern, since the ADC in the 71M6515H has enough resolution, even when operating at 120Vrms or 240Vrms. If a different set of voltage dividers or an external voltage transformer is to be used, scaling techniques similar to those applied for the current transformer should be used. In the following example we assume that the line voltage is not applied to the resistor divider for VA formed by R15-R21, R26-R31, and R32, but to a voltage transformer with a ratio N of 20:1, followed by a simple resistor divider. We also assume that we want to maintain the value for VMAX at 600V to provide headroom for large voltage excursions. When applying VMAX at the primary side of the transformer, the secondary voltage Vs is: Vs = VMAX / N Vs is scaled by the resistor divider ratio RR. When the input voltage to the voltage channel of the 71M6515H is the desired 177mV, Vs is then given by: Vs = RR * 177mV Resolving for RR, we get: RR = (VMAX / N) / 177mV = (600V / 30) / 177mV = 170.45 This divider ratio can be implemented, for example, with a combination of one 16.95kΩ and one 100Ω resistor. Revision 2.0 25 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 1.9 CALIBRATING THE DEMO METER The general calibration procedure is as follows: 1. Obtain the deviation from ideal accuracy using a meter calibration system (see section 2.1). 2. Calculate the calibration values using the error terms obtained in step 1 (see section 2.1). 3. Enter the calibration values generated in step 2 using the GUI. 4. Test the meter with the new calibration constants. Revision 2.0 26 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 2 2 APPLICATION INFORMATION 2.1 CALIBRATION PROCEDURE In this section, requirements for calibration systems will be discussed, and calibration procedures will be suggested. Sample calibration procedures for CT/shunt meters are provided requiring three or five measurements. A sample calibration procedure is provided for Rogowski meters. 2.1.1 CALIBRATION SYSTEMS Performing a proper calibration requires that a calibration system is used, i.e. equipment that applies accurate voltage, load current and load angle to the unit being calibrated, while measuring the response from the unit being calibrated in a repeatable way. By repeatable we mean that the calibration system is synchronized to the meter being calibrated. Best results are achieved when the first pulse from the meter opens the measurement window of the calibration system. This mode of operation is opposed to a calibrator that opens the measurement window at random time and that therefore may or may not catch certain pulses emitted by the meter. It is also very important that the calibration system, just like the hookup of a real meter, applies voltage constantly while varying the current. For the calibration of the 71M6515H it is essential that voltage is applied at least a few seconds before the measurement is started, i.e. before current is applied. This is necessary because: • In case the internal power supply is used, the 71M6515H needs a few seconds to power up. • Even if the 71M6515H has DC power (V3P3), filters and other functions inside the CE require time to get synchronized in order to obtain accurate measurements. For a typical energy calibration, a meter calibration system is used to apply a calibrated load, e.g. 240V at 30A, while interfacing the voltage and current sensors to the 71M6515H. This load should result in an observable pulse rate at the WPULSE output depending on the selected energy per pulse. For example, 7.2kW will result in a pulse rate corresponding to 7200Wh/3600s = 2Wh/s. Most calibration systems provide ways to evaluate the observed pulse rate by comparing it to the ideal pulse rate. 2.1.2 DEFINITIONS Each meter phase must be calibrated individually. The PHADJ equations apply only when a current transformer is used for the phase in question. If a Rogowski coil is used, the phase compensation should be correct by default and adjustments are required only to CAL_Ix and CAL_Vx. Note that positive load angles correspond to lagging current (see Figure 2-1). The calibration procedures described below should be followed after interfacing the voltage and current sensors to the 71M6515H chip. When properly interfaced, the V3P3 power supply is connected to the meter neutral and is the DC reference for each input. Each voltage and current waveform, as seen by the 71M6515H, is scaled to be less than 250mV (peak). Revision 2.0 27 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual Voltage Current lags voltage (inductive) Positive direction +60° Current -60° Current leads voltage (capacitive) Voltage Generating Energy Using Energy Figure 2-1: Phase Angle Definitions 2.1.3 ERROR SOURCES IN A METER (CT/SHUNT RESISTOR) A typical meter has phase and gain errors as shown by φS, AXI, and AXV in Figure 2-2. Following the typical meter convention of current phase being in the lag direction, the small amount of phase lead in a typical current sensor is represented as -φS. The errors shown in Figure 2-2 represent the sum of all gain and phase errors. They include errors in voltage attenuators, current sensors, and in ADC gains. In other words, no errors are made in the ‘input’ or ‘meter’ boxes. INPUT I φL φ L is phase lag ERRORS −φS METER IRMS A XI Π V IDEAL = I , φS is phase lead W V RMS AXV ERROR ≡ ACTUAL = I AXI IDEAL = IV cos(φ L ) ACTUAL = IV AXI AXV cos(φ L − φ S ) IDEAL = V , ACTUAL = V AXV ACTUAL − IDEAL = ACTUAL − 1 IDEAL IDEAL Figure 2-2: Watt Meter with Gain and Phase Errors During the calibration phase, we measure errors and then introduce correction factors to nullify their effect. With three unknowns to determine, we must make at least three measurements. If we make more measurements, we can average the results. Revision 2.0 28 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 2.1.4 CALIBRATION WITH THREE MEASUREMENTS The simplest calibration method is to make three measurements. Typically, a voltage measurement and two Watt-hour (Wh) measurements are made. We assume the voltage measurement has the error EV, and the two Wh measurements have errors E0 and E60, where E0 is measured with φL = 0 and E60 is measured with φL = 60. These values should be simple ratios—not percentage values. They should be zero when the meter is accurate and negative when the meter runs slow. The fundamental frequency is f0. T is equal to 1/fS, where fS is the sample frequency (2560.62Hz). Set all calibration factors to nominal: CAL_IA = 16384, CAL_VA = 16384, PHADJ_A = 0. From the voltage measurement, we determine that 1.Î AXV = EV + 1 We use the other two measurements to determine φS and AXI. IV AXV AXI cos(0 − φ S ) − 1 = AXV AXI cos(φ S ) − 1 IV cos(0) 2. E0 = 2a. AXV AXI = 3. E 60 = IV AXV AXI cos(60 − φ S ) cos(60 − φ S ) − 1 = AXV AXI −1 IV cos(60) cos(60) 3a. E 60 = AXV AXI [cos(60) cos(φ S ) + sin(60) sin(φ S )] −1 cos(60) E0 + 1 cos(φ S ) = AXV AXI cos(φ S ) + AXV AXI tan(60) sin(φ S ) − 1 Combining 2a and 3a: 4. E 60 = E 0 + ( E 0 + 1) tan(60) tan(φ S ) 5. tan(φ S ) = 6.Î φ S = tan −1  E 60 − E 0 ( E 0 + 1) tan(60)  E 60 − E 0  ( E 1 ) tan( 60 ) +   0  and from 2a: 7.Î AXI = E0 + 1 AXV cos(φ S ) Now that we know the AXV, AXI, and φS errors, we calculate the new calibration voltage gain coefficient from the previous ones: CAL _ V NEW = CAL _ V AXV We calculate PHADJ from φS, the desired phase lag: [ ]   tan(φ S ) 1 + (1 − 2 −9 ) 2 − 2(1 − 2 −9 ) cos(2πf 0T ) PHADJ = 2 20   −9 −9  (1 − 2 ) sin( 2πf 0T ) − tan(φ S ) 1 − (1 − 2 ) cos(2πf 0T )  [ ] And we calculate the new calibration current gain coefficient, including compensation for a slight gain increase in the phase calibration circuit. Revision 2.0 29 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual CAL _ I AXI CAL _ I NEW = 2.1.5 1 1+ 2 − 20 PHADJ (2 + 2 PHADJ − 2(1 − 2 −9 ) cos(2πf 0T )) 1 − 2(1 − 2 −9 ) cos(2πf 0T ) + (1 − 2 −9 ) 2 − 20 CALIBRATION WITH FIVE MEASUREMENTS The five measurement method provides more orthogonality between the gain and phase error derivations. This method involves measuring EV, E0, E180, E60, and E300. Again, set all calibration factors to nominal, i.e. CAL_IA = 16384, CAL_VA = 16384, PHADJ_A = 0. First, calculate AXV from EV: 1.Î AXV = EV + 1 Calculate AXI from E0 and E180: IV AXV AXI cos(0 − φ S ) − 1 = AXV AXI cos(φ S ) − 1 IV cos(0) 2. E0 = 3. E180 = 4. E 0 + E180 = 2 AXV AXI cos(φ S ) − 2 5. AXV AXI = 6.Î AXI = IV AXV AXI cos(180 − φ S ) − 1 = AXV AXI cos(φ S ) − 1 IV cos(180) E 0 + E180 + 2 2 cos(φ S ) ( E 0 + E180 ) 2 + 1 AXV cos(φ S ) Use above results along with E60 and E300 to calculate φS. 7. E 60 = IV AXV AXI cos(60 − φ S ) −1 IV cos(60) = AXV AXI cos(φ S ) + AXV AXI tan(60) sin(φ S ) − 1 8. E300 = IV AXV AXI cos(−60 − φ S ) −1 IV cos(−60) = AXV AXI cos(φ S ) − AXV AXI tan(60) sin(φ S ) − 1 Subtract 8 from 7 9. E 60 − E300 = 2 AXV AXI tan(60) sin(φ S ) use equation 5: E 0 + E180 + 2 tan(60) sin(φ S ) cos(φ S ) 10. E 60 − E300 = 11. E 60 − E300 = ( E 0 + E180 + 2) tan(60) tan(φ S ) 12.Î φ S = tan −1   ( E 60 − E300 )  tan( 60 )( E E 2 ) + + 0 180    Revision 2.0 30 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual Now that we know the AXV, AXI, and φS errors, we calculate the new calibration voltage gain coefficient from the previous ones: CAL _ V NEW = CAL _ V AXV We calculate PHADJ from φS, the desired phase lag: [ ]   tan(φ S ) 1 + (1 − 2 −9 ) 2 − 2(1 − 2 −9 ) cos(2πf 0T ) PHADJ = 2 20   −9 −9  (1 − 2 ) sin( 2πf 0T ) − tan(φ S ) 1 − (1 − 2 ) cos(2πf 0T )  [ ] And we calculate the new calibration current gain coefficient, including compensation for a slight gain increase in the phase calibration circuit. CAL _ I NEW = 2.1.6 CAL _ I AXI 1 1+ 2 − 20 PHADJ (2 + 2 PHADJ − 2(1 − 2 −9 ) cos(2πf 0T )) 1 − 2(1 − 2 −9 ) cos(2πf 0T ) + (1 − 2 −9 ) 2 − 20 CALIBRATION FOR METERS WITH ROGOWSKI COIL SENSORS Rogowski coils generate a signal that is the derivative of the current. The 6515H Rogowski module implemented in the Rogowski CE image digitally compensates for this effect and has the usual gain and phase calibration adjustments. Additionally, calibration adjustments are provided to eliminate voltage coupling from the sensor input. Current sensors built from Rogowski coils have a relatively high output impedance that is susceptible to capacitive coupling from the large voltages present in the meter. The most dominant coupling is usually capacitance between the primary of the coil and the coil’s output. This coupling adds a component proportional to the derivative of voltage to the sensor output. This effect is compensated by the voltage coupling calibration coefficients. As with the CT procedure, the calibration procedure for Rogowski sensors uses the meter’s display to calibrate the voltage path and the pulse outputs to perform the remaining energy calibrations. The calibration procedure must be done to each phase separately, making sure that the pulse generator is driven by the accumulated real energy for just that phase. In other words, the pulse generator input should be set to WhA, WhB, or WhC, depending on the phase being calibrated. The IC has to be configured for Rogowski mode (IMAGE=01). In preparation of the calibration, all calibration parameters are set to their default values. VMAX and IMAX are set to reflect the system design parameters. WRATE and PUSE_SLOW, PULSE_FAST are adjusted to obtain the desired Kh. Step 1: Basic Calibration: After making sure VFEED_A, VFEED_B, and VFEED_C are zero, perform either the three measurement procedure (2.1.4) or the five measurement calibration procedure (2.1.5) described in the CT section. Perform the procedure at a current large enough that energy readings are immune from voltage coupling effects. The one exception to the CT procedure is the equation for PHADJ—after the phase error, φs, has been calculated, use the PHADJ equation shown below. Note that the default value of PHADJ is not zero, but rather –3973. PHADJ = PHADJ PREVIOUS − φ S 1786 50 f0 If voltage coupling at low currents is introducing unacceptable errors, perform step 2 below to select nonzero values for VFEED_A, VFEED_B, and VFEED_C. Revision 2.0 31 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual Step 2: Voltage Cancellation: Select a small current, IRMS, where voltage coupling introduces at least 1.5% energy error. At this current, measure the errors E0 and E180 to determine the coefficient VFEED . VFEED = 2.1.7 E 0 − E180 25 I RMS VMAX − VFEEDPREVIOUS 2 2 I MAX VRMS CALIBRATION SPREADSHEETS Calibration spreadsheets are available from TERIDIAN Semiconductor. Figure 2-3 shows the spreadsheet used for three measurements. Figure 2-3 shows the calibration spreadsheet used for five measurements. 71M6511/71M6513/71M6515 Calibration Worksheet Three Measurements Enter values in yellow fields Results will show in green fields… 50 AC frequency: [Hz] (click on yellow field to select from pull-down list) % fraction PHASE A: Energy reading at 0° 0 0 Energy reading at +60° 0 0 Voltage reading at 0° 0 0 Expected voltage Measured voltage 240 240 PHASE B: Energy reading at 0° Energy reading at +60° Energy reading at 0° 10 10 10 Expected voltage Measured voltage 240 264 PHASE C: Energy reading at 0° Energy reading at +60° Energy reading at 0° Expected voltage Measured voltage -3.8 -15.4 -3.8 REV Date: 4.0 9/28/2005 WJH Author: CAL_IA CAL_VA PHADJ_A Voltage 16384 16384 0 Positive direction 0.1 0.1 0.1 CAL_IB CAL_VB PHADJ_B 16384 14895 0 -0.038 -0.154 -0.038 CAL_IC CAL_VC PHADJ_C 16357 17031 -12434 Current lags voltage (inductive) +60° Current -60° Current leads voltage (capacitive) Voltage Generating Energy Using Energy Readings: Enter 0 if the error is 0%, 240 230.88 enter -3 if meter runs 3% slow. Figure 2-3: Calibration Spreadsheet for Three Measurements Revision 2.0 32 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 71M6511/71M6513/71M6515 Calibration Worksheet Five Measurements PI Results will show in green fields… Enter values in yellow fields! REV Date: 0.023803667 Ts [Hz] AC frequency: 60 (click on yellow field to select from pull-down list) PHASE A: % fraction Energy reading at 0° 2 0.02 CAL_IA Energy reading at +60° 2.5 0.025 CAL_VA Energy reading at -60° 1.5 0.015 PHADJ_A Energy reading at 180° 2 0.02 Voltage error at 0° 1 0.01 Expected voltage PHASE B: Energy reading at 0° Energy reading at +60° Energy reading at -60° Energy reading at 180° Voltage error at 0° Expected voltage PHASE C: Energy reading at 0° Energy reading at +60° Energy reading at -60° Energy reading at 180° Voltage error at 0° Expected voltage 240 242.4 % 2 2 2 2 1 fraction 0.02 0.02 0.02 0.02 0.01 240 242.4 % 0 0 0 0 0 fraction 0 0 0 0 0 240 240 Author: Voltage 16219 16222 445 Positive direction Measured voltage CAL_IB CAL_VB PHADJ_B 4.0 9/28/2005 WJH +60° Current -60° 16223 16222 0 Current leads voltage (capacitive) Voltage Measured voltage Generating Energy CAL_IC CAL_VC PHADJ_C Current lags voltage (inductive) 16384 16384 0 Using Energy Readings: Enter 0 if the error is 0%, enter +5 if meter runs 5% fast, enter -3 if meter runs 3% slow. Measured voltage Figure 2-4: Calibration Spreadsheet for Five Measurements 2.1.8 COMPENSATING FOR NON-LINEARITIES Nonlinearity is most noticeable at low currents, as shown in Figure 2-5, and can result from input noise and truncation. Nonlinearities can be eliminated using the QUANT_W variable. 12 error [%] 10 error 8 6 4 2 0 0.1 1 10 100 I [A] Figure 2-5: Non-Linearity Caused by Quantification Noise The error can be seen as the presence of a virtual constant noise current. While 10mA hardly contribute any error at currents of 10A and above, the noise becomes dominant at small currents. Revision 2.0 33 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual The value to be used for QUANT can be determined by the following formula: error V ⋅I 100 QUANT _ W = − VMAX ⋅ IMAX ⋅ LSB Where error = observed error at a given voltage (V) and current (I), VMAX = voltage scaling factor, as described in section 1.8 IMAX = current scaling factor, as described in section 1.8 -10 LSB = QUANT LSB value = 7.4162*10 W Example: Assuming an observed error as in Figure 2-5, we determine the error at 1A to be +1%. If VMAX is 600V and IMAX = 208A, and if the measurement was taken at 240V, we determine QUANT as follows: 1 240 ⋅ 1 100 QUANT _ W = − = −11339 600 ⋅ 208 ⋅ 7.4162 ⋅ 10 −10 QUANT_W is to be written to the CE location 0x2F. It does not matter which current value is chosen as long as the corresponding error value is significant (5% error at 0.2A used in the above equation will produce the same result for QUANT_W). Input noise and truncation can cause similar errors in the VAR calculation that can be eliminated using the QUANT_VAR variable. QUANT_VAR is determined using the same formula as QUANT_W. Revision 2.0 34 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 2.2 SCHEMATIC INFORMATION In this section, hints on proper schematic design are provided that will help designing circuits that are functional and sufficiently immune to EMI (electromagnetic interference). 2.2.1 COMPONENTS FOR THE VFLT PIN The VFLT pin (pin 59) of the 71M6515H must never be left unconnected. A voltage divider should be used to establish that the voltage at VFLT is in a safe range when the meter is in mission mode (see Figure 2-6). VFLT must be lower than 2.9V in all cases in order to keep the hardware watchdog timer enabled. R83 V3P3 10K L12 VFLT D11 C20 10uF UCLAMP3301D FERRITE R86 21.5K C41 0.1uF C42 1000pF GND Figure 2-6: Voltage Divider for VFLT 2.2.2 RESET CIRCUIT Even though a functional meter will not necessarily need a reset switch, the 71M6515H Demo Boards provide a reset pushbutton (SW2) that can be used when prototyping and debugging software. When a circuit is used in an EMI environment, the RESETZ pin should be supported by the external components shown in Figure 2-7. R75 should be in the range of 200Ω, R77 should be around 10Ω. The capacitor C38 should be 1000pF. R75 and C38 should be mounted as close as possible to the IC. In cases where the trace from the pushbutton switch to the RESETZ pin poses an EMI problem, R77 can be removed. V3P3 SW2 PB-SW R75 200 R77 RESETZ 10 C18 NC C38 1000pF GND Figure 2-7: External Components for RESETZ 2.2.3 OSCILLATOR The oscillator of the 71M6515H drives a standard 32.768kHz watch crystal (see Figure 2-8). Crystals of this type are accurate and do not require a high current oscillator circuit. The oscillator in the 71M6515H has been designed specifically to handle watch crystals and is compatible with their high impedance and limited power handling capability. The oscillator power dissipation is very low to maximize the lifetime of any battery backup device attached to the VBAT pin. Revision 2.0 35 of 66 © Copyright 2005 TERIDIAN Semiconductor Corporation 71M6515H Demo Board User’s Manual 71M651X 71M6515H 10pF XIN crystal XOUT 10pF Figure 2-8: Oscillator Circuit Note: It is not necessary to place an external resistor across the crystal, i.e. R91 on the 4-Layer Demo Board must not be populated. Note: Capacitor values for the crystal must be