AEDB-9140-A06

AEDB-9140 Series Three Channel Optical Incremental Encoder Modules with Codewheel, 100 CPR to 500 CPR Data Sheet Description Features The AEDB-9140 series are three channel optical incremental encoder modules offered with a codewheel. When used with a codewheel, these low cost modules detect rotary position. Each module consists of a lensed LED source and a detector IC enclosed in a small plastic package. Due to a highly collimated light source and a unique photodetector array, these modules are extremely tolerant to mounting misalignment. • Two Channel Quadrature Output with Index Pulse The AEDB-9140 has two channel quadrature outputs plus a third channel index output. This index output is a 90 electrical degree high true index pulse which is generated once for each full rotation of the codewheel. • Operating Temperature: -10°C to 85°C The AEDB-9140 is designed for use with a codewheel which has an optical radius of 11.00 mm (0.433 inch). Applications The quadrature signals and the index pulse are accessed through five 0.46 mm square pins located on 1.27 mm(pitch) centers. The AEDB-9140 provide sophisticated motion control detection at a low cost, making them ideal for high volume applications. Typical applications include printers, plotters, tape drives, and industrial and factory automation equipment. • Resolution from 100 CPR to 500 CPR (Counts Per Revolution) • Low Cost • Easy to Mount • No Signal Adjustment required • Small Size • TTL Compatible • Single 5V Supply Note: Avago Technologies encoders are not recommended for use in safety critical applications. Eg. ABS braking systems, power steering, life support systems and critical care medical equipment. Please contact sales representative if more clarification is needed. Ordering Information Theory of Operation The AEDB-9140 are emitter/detector modules. Coupled with a codewheel, these modules translate the rotary motion of a shaft into a three-channel digital output. AEDB-9140 Option Resolutions (Cycle/Rev) Shaft Diameter* C - 100 CPR E - 200 CPR F - 256 CPR G - 360 CPR H - 400 CPR A - 500 CPR 02 - 3mm 04 - 5/32 in 05 - 3/16 in 06 - 1/4 in 11 - 4mm 12 - 6mm 13 - 8mm 14 - 5mm As seen in Figure 1, the modules contain a single Light Emitting Diode (LED) as its light source. The light is collimated into a parallel beam by means of a single polycarbonate lens located directly over the LED. Opposite the emitter is the integrated detector circuit. This IC consists of multiple sets of photodetectors and the signal processing circuitry necessary to produce the digital waveforms. Three Channel Encoder Modules with Codewheel, 11 mm Optical Radius * Please contact factory for other shaft diameters Available Options Shaft Diameter Options Part No AEDB-9140 CPR 02 04 05 • C • • • F G • H • A 11 • E 2 06 • • • • 12 13 • • 14 • • • • • • • • • • • The codewheel rotates between the emitter and detector, causing the light beam to be interrupted by the pattern of spaces and bars on the codewheel. The photodiodes which detect these interruptions are arranged in a pattern that corresponds to the radius and design of the code-wheel. These detectors are also spaced such that a light period on one pair of detectors corresponds to a dark period on the adjacent pair of detectors. The photodiode outputs are then fed through the signal processing circuitry resulting in A, Abar, B, Bbar, I and Ibar. Comparators receive these signals and produce the final outputs for channels A and B. Due to this integrated phasing technique, the digital output of channel A is in quadrature with that of channel B (90 degrees out of phase). Block Diagram RESISTOR VCC 4 PHOTO DIODES COMPARATORS LENS A A B LED B I I + CH. A − 3 + CH. B − 5 + CH. I − INDEXPROCESSING CIRCUITRY SIGNAL PROCESSING CIRCUITRY 2 GND 1 CODE WHEEL EMITTER SECTION DETECTOR SECTION Figure 1. Output Waveforms C P 2.4 V 0.4 V AMPLITUDE φ S1 S2 S3 S4 2.4 V 0.4 V t2 t1 2.4 V 0.4 V P0 ROTATION Figure 2. 3 CH. A CH. B CH. I Definitions Note: Refer to Figure 2 Count (N): The number of bar and window pairs or counts per revolution (CPR) of the codewheel. State Width Error (ΔS): The deviation, in electrical degrees, of each state width from its ideal value of 90°e. One Cycle (C): 360 electrical degrees (°e), 1 bar and window pair. Phase (f ): The number of electrical degrees between the center of the high state of channel A and the center of the high state of channel B. One Shaft Rotation: 360 mechanical degrees, N cycles. Position Error (ΔΘ): The normalized angular difference between the actual shaft position and the position indicated by the encoder cycle count. Cycle Error (ΔC): An indication of cycle uniformity. The difference between an observed shaft angle which gives rise to one electrical cycle, and the nominal angular increment of 1/N of a revolution. Pulse Width (P): The number of electrical degrees that an output is high during 1 cycle. This value is nominally 180°e or 1/2 cycle. Pulse Width Error (ΔP): The deviation, in electrical degrees, of the pulse width from its ideal value of 180°e. State Width (S): The number of electrical degrees between a transition in the output of channel A and the neighboring transition in the output of channel B. There are 4 states per cycle, each nominally 90°e. 4 This value is nominally 90°e for quadrature output. Phase Error (Δφ): The deviation of the phase from its ideal value of 90°e. Direction of Rotation: When the codewheel rotates in the clockwise direction viewing from top of the module (direction from V to G), channel A will lead channel B. If the codewheel rotates in the opposite direction, channel B will lead channel A. Optical Radius (Rop): The distance from the codewheel’s center of rotation to the optical center (O.C) of the encoder module. Index Pulse Width (Po): The number of electrical degrees that an index is high during one full shaft rotation. This value is nominally 90°e or 1/4 cycle. Absolute Maximum Ratings Parameter Symbol Minimum Maximum Units Storage Temperature TS -10 Typical 85 °C Operating Temperature TA -10 85 °C Supply Voltage VCC -0.5 7 Volts Output Voltage VO -0.5 VCC Volts Output Current per Channel, Iout IOUT -1.0 18 mA Parameter Symbol Min. Temperature TA -10 Supply Voltage VCC 4.5 Load Capacitance Frequency Notes Recommended Operating Conditions Typ. Max. Units 85 °C 5.5 Volts Ripple < 100mVp-p CL 100 pF 2.7 kΩ pull-up f 100 kHz Velocity (rpm) x N/60 Shaft Perpendicularity Plus Axial Play ± 0.20(± 0.008) mm(in.) Refer to Mounting Consideration Shaft Eccentricity Plus Radial Play ± 0.04(± 0.0015) mm(in.) 5.0 Notes Electrical Characteristics Electrical Characteristics Over the Recommended Operating Range. Typical Values at 25°C. Parameter Symbol Minimum Typical Maximum Units Supply Current ICC 30 57 85 mA High Level Output Voltage VOH 2.4 Low Level Output Voltage VOL Rise Time tr Fall Time tf Note: Typical values specified at Vcc = 5.0 V and 25 °C 5 Notes V Typ. IOH = -0.5 mA V Typ. IOL = 10 mA 180 ns 50 ns CL = 25 pFRL = 2.7 kΩ pull-up 0.4 Encoding Characteristics Encoding Characteristics Over the Recommended Operating Conditions and Recommended Mounting Tolerances unless otherwise specified. Parameter Symbol Typical Maximum Units Cycle Error ΔC Minimum 3 10 °e Pulse Width Error ΔP 7 30 °e Logic State Width Error ΔS 5 30 °e Phase Error Δφ 2 15 °e Position Error ΔΘ 10 40 min. of arc Index Pulse Width Po 60 90 120 °e CH I rise afterCH B or CH A fall -10°C to + 85°C t1 10 100 1000 ns CH I fall afterCH A or CH B rise -10°C to + 85°C t2 10 300 1000 ns Notes Electrical Interface Customized Solutions To insure reliable encoding performance, the AEDB-9140 three channel encoder modules require 2.7 kΩ (± 10%) pull-up resistors on output pins 2, 3, and 5 (Channels A, I and B) as shown in Figure 3. These pull-up resistors should be located as close to the encoder module as possible (within 4 feet). Each of the three encoder module outputs can drive a single TTL load in this configuration. Customization of codewheel CPR is possible. It has to be based on the encoder LPI table given below: Figure 3. 6 Part Number LPI AEDB-9140 # C 36.7 AEDB-9140 # E 73.5 AEDB-9140 # F 94 AEDB-9140 # G 132.3 AEDB-9140 # H 147 AEDB-9140 # A 183 Note: The customization of codewheel method is valid from theoretical standpoint. However Avago Technologies strongly recommends a full characterization to be done to determine the actual performance of the encoder with customized codewheel. CPR calculation formula: CPR = (LPI x 25.4) x 2 x π x ROP Where: CPR = Counts Per Revolutions LPI = Encoder LPI provided in the table ROP = Encoder Optical Radius in mm * Recommended maximum Codewheel diameter should not exceed 30mm Characterization means validating the encoding performance (consist of cycle error, pulse width error, logic state width error, phase error, position error & index pulse width , index channel rise and fall time) over the recommended operating conditions and recommended mounting tolerances. Mounting Considerations SHAFT CENTER AXIS OPTICAL CENTER AXIS ARTWORK GAP TYPICAL 0.50 EG R0.89 Codewheel MOUNTING PLANE Rop MOUNTING BOSS 2MM DIA. 2 PLACES 6.30 ET OPTICAL CENTER AXIS 12.60 Recommended Screw Size: M1.6 x 0.35 Recommended Mounting Screw Torque : 1 Lbin (0.113 Nm) ER Note: These dimensions include shaft endplay and codewheel warp. All dimension for mounting the module and codewheel should be measured with respect to two mounting boss, as shown above. Error Rop = 11mm Unit Notes EG Gap ± 0.20 mm Recommend to mount the codewheel closer to the detector side (upper side) for optimum encoder performance. ER Radial ± 0.13 mm ET Tangential ± 0.13 mm 7 Package Dimension Optical Center Axis 17.80 21.60 R15.50 3.00 1.60 4.40 Optical Center Axis 2.69 3.69 Top View 5.34 1.17 13.60 Optical Center Axis 1.27 0.46 3.69 3.00 2.40 13.6 Front View 1.78 4.00 4.90 R0.89 0.80 1.6 Side View 2.00 21.60 TYPICAL DIMENSIONS IN MILLIMETERS Codewheel Mechanical Drawing 5.95 (0.234) MAX. 1.80 (0.071) 25.7 (1.01) DIA. MAX. MOUNTING BOSS SETSCREW INDEX PULSE REFERENCE MARKER INDEX PULSE POSITION ROP = 11.00 mm (0.433 in.) DIMENSIONS IN MM (INCHES) 8 130˚ ± 5˚ TYPICAL 12.70 (0.500) MAX. 10.16 (0.400) 3.58 (0.141) For product information and a complete list of distributors, please go to our web site: www.avagotech.com Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies in the United States and other countries. Data subject to change. Copyright © 2005-2009 Avago Technologies. All rights reserved. Obsoletes 5989-3823EN AV02-1584EN - Janaury 4, 2010