ASF1400

ASF1400 Bidirectional Mass Flow Meter _ Unique dynamic range: 0.01 sccm – 400 sccm _ Outstanding resolution and accuracy _ Ultra fast response time _ Hysteresis & offset free _ Calibrated & temperature compensated _ RS-232 and Version 2.2 / November ASF1400 Product Summary The ASF1400 Mass Flow Meter enables extremely accurate bidirectional measurement of gas flow over four orders of magnitude. Its leading performance is based on SENSIRION’s unsurpassed CMOSens® sensor technology. With CMOSens®, the on-chip sensor element forms an integrated whole with the amplification and A/D converter circuit. This results in superior resolution, fast response time and large dynamic range at lowest power consumption. All measurement data is fully calibrated and temperature compensated by means of an internal microcontroller. Mounted in rugged, chemically inert PBT housing the ASF1400 is suitable for a wide range of applications. Such include mass flow metering for process control, medical applications, heating ventilation and air conditioning (HVAC) solutions, as well as gas flow metrology. The sensor housing provides two inlets for measuring the gas flow and withstands overpressures of 2 bar (29 psi). The ASF1400 requires a supply voltage of 7…18Vdc and provides an RS-232 compliant electrical interface. ASF1400 MASS FLOW METER MASS FLOW GND VDD Power Supply MICRO CONTROLLER /CS MOSI MISO SCK SPI no longer Interface supported RxD TxD RS232 Interface RS232 LINE DRIVER/ RECEIVER ADC AMPLIFIER THERMAL SENSOR CMOSens™ SENSOR CHIP VOLTAGE REGULATOR EEPROM MASS FLOW Figure 1: Block Diagram ASF1400 Mass Flow Sensor with CMOSens® technology. www.sensirion.com Sensirion AG, Laubisrütistrasse 50, CH-8712 Stäfa ZH, Switzerland, Phone: +41 44 306 40 00, Fax: +41 44 306 40 30 ASF1400 Bidirectional Mass Flow Meter Introductory Description The heart of the ASF1400 mass flow meter is powered by Sensirion’s unsurpassed CMOSens® sensor technology. The ASF1400 mass flow meter therefore provides unbeatable performance at very attractive system cost. The lowest detectable gas flow rate is 0.003 sccm, which means a minimum volume of 3 mm3 gas per minute can be measured. Covering at the same time a flow range of more than 4 orders of magnitude, the ASF1400 sets a new standard wherever mass flow has to be measured or controlled. The ASF1400 device measures true mass flow independent of the ambient temperature and pressure changes. You simply connect the gas to be measured to the ASF1400 device to get an instantaneous gas flow rate at a sampling rate of up to 7Hz (please contact us for sampling rates of up to 200Hz). A flow range between ±400 sccm can directly be mea-sured by connecting the ASF1400. To increase the range, a bypass can be used in conjunction with the ASF1400 device (see Section 1.4 of this data sheet). In addition to mass flow, the ASF1400 device provides information about the temperature on the CMOSens® sensor element. Both mass flow and temperature data are accessed through an RS-232. The RS-232 interface allows you to directly connect the ASF1400 device to a PC or PDA using standard terminal software. If a special interface such as 4-20 mA current output or other is required contact Sensirion for a customer specific solution. In general, all gas types can be measured using the ASF1400 product. However, the standard calibration www.sensirion.com gas is nitrogen. Please contact SENSIRION, if you would like to use the sensor for applications with other gases. To get you started quickly, an evaluation package including ASF1400 devices, software, cables, rubber hose and bypass is available from Sensirion AG. CMOSens® sensor technology CMOSens® is the base technology for all Sensirion multi sensor modules and sensor systems. The unification of semiconductor chip and sensor technology serves as a platform for highly integrated system solutions with excellent sensor precision and reliability. With CMOSens®, the on-chip sensor element forms an integrated whole with a high-end amplification and A/D converter circuit. Due to the compact single-chip design, CMOSens® based sensors are very resistant to electromagnetic disturbances (EMC), another important technical advantage of this state of the art sensor technology. As a result, CMOSens® based multi sensor modules offer excellent sensor precision, fast response time and a very large dynamic measurement range. In addition, the digital intelligence of the CMOSens® sensor technology enables digital interfaces that permit an easy link with the system of the customer, a real advantage and benefit that results in ready-to-use problem solutions (“Mount&Sense”). Version 2.2 2/9 ASF1400 Bidirectional Mass Flow Meter 1 Mass Flow Sensor Performance Table 1: Overview of ASF1400 Gas Sensor Performance 1 Parameter Condition Minimum Typical Maximu m Units Flow Sensor Dynamic Range Resolution Lowest Detectable Flow Pressure Drop direct measurement -400 (2 3 ) using proposed bypass tube -100 customized bypass tube unlimited 400 sccm flow < 10 sccm flow < 10 sccm flow 400 sccm, pabs. = 1 bar Repeatability Accuracy 23 C Offset Overpressure Resistance ( 8 ) 23°C Response Time ( 9 ) Operating Temperature Ambient Temperature Coefficient Position Sensitivity Temperature Sensor Dynamic Range Resolution Accuracy 0…5 % of full scale 5…100 % of full scale depends on resolution setting (see Section 3, Table 2) 400 100 unlimited sccm( 2 ) liter/min( 4 ) 0.09 0.01 sccm sccm 0.015(4) sccm 120 0.0025 % FS ( 6 ) 0.025 % m.v. 0.05 % FS ( 7 ) 1 % m.v. (7) < 0.005 Pa( 5 ) < 0.02 % FS 2 bar 142 1280 ms 0 70 °C Zero < 0.005 Span < 0.08 pabs=1 bar, small nitrogen flow ±0.008 % FS / °C % measured value / °C % FS Measures temperature inside the sensor, but not of the surrounding air(10 10 ) 0 3 70 0.1 2 °C °C °C All data apply for calibration conditions (20°C, 1013 mbar) unless otherwise noted. 1 sccm = 1 cm3/min at 0°C and 1013mbar pressure (1sccm = 0.001 norm liter) 3 using bypass tube included in Sensirion’s mass flow meter evaluation kit EK-F1 4 1 liter/min = 1000 sccm 5 1 bar = 100 000 Pa = 0.9869 atm = 401.9 inch H2O = 14.5 psi 6 Error = % of full scale (FS) or % of measured value, whichever is bigger. 7 Better calibration available for high volume OEM on request. Allow the Sensor to warm up for best results. 8 For higher overpressure resistance versions please check the EM1 product page. 9 For faster response times please check out the ASF1430 high speed mass flow meter data sheet 10 The sensor warms up by about 7°C (depending on supply voltage and ventilation). 1 2 www.sensirion.com Version 2.2 3/9 ASF1400 Bidirectional Mass Flow Meter 1.1 Gas Flow Characteristics Figure 2 shows the applied gas flow vs. the digital output of the ASF1400. The ASF1400 is calibrated for mass flow measurements. However, there is a well defined relation between mass flow and pressure drop. This relation is shown in Figure 4. On request the ASF1400 can also be calibrated for the pressure drop at its output (for more details refer to the documentation of the Sensirion Differential Pressure Sensor ASP1400). 250 0 -250 -500 -500 -250 0 250 150 500 Mass Flow [sccm] Figure 2: ASF1400 transfer characteristics. 1.2 Sensor Principle and Gas Types The ASF1400 device detects mass gas flow by measuring heat transfer. A heating resistor on a thermally insulated membrane is kept above ambient temperature. In the presence of gas flow, the temperature distribution up- and downstream is disturbed. This asymmetry is then measured. Due to the minimal thermal mass of the membrane, symmetrical arrangement, and accurate temperature measurement, the revolutionary specifications of the ASF1400 devices are achieved. The above mentioned thermal principle requires information about the gas type to be measured. The ASF1400 is available for air and nitrogen. Other gas types are available on request. In Figure 3 the repeatability of the ASF1400 devices is compared with the repeatability of a typical Mass Flow Controller (MFC). It emphasizes the superior performance of the ASF1400 device. Differential pressure [Pa] ASF1400 output [sccm] 500 100 50 0 - 50 - 100 - 150 - 400 - 200 0 200 Massflow [sccm] 400 Figure 4: Differential Pressure vs. Mass Flow of ASF1400 Device. 1.4 Adjusting the Measurement Range To adjust the measurement range, the ASF1400 device is used in conjunction with a bypass configuration (see Figure 5). Only a sample of the total flow actually gets directed through the bypass channel and the sensor system. A tube with flow restrictor and all required connection items are included in the Mass Flow Meter Evaluation Kit EKF1, also available from SENSIRION AG. 0.5 ASF 1400 Repeatability [% of measured value] 1.3 Gas Flow and Pressure Difference Specs of typical MFC 0.4 Repeatability ASF 1400 0.3 Flow restrictor 0.2 0.1 0 0 100 200 Massflow [sccm] 300 400 Figure 3: Comparison of the repeatability of the CMOSens® ASF1400 device compared to a typical Mass Flow Controller (MFC). www.sensirion.com Figure 5: Extending the measurement range of the ASF1400 device using a bypass configuration. Only a sample of the total flow actually gets directed through the bypass channel and the sensor. Shown tube with flow restrictor is included in the EK-F1 evaluation kit. Version 2.2 4/9 ASF1400 Bidirectional Mass Flow Meter The measurement values are provided as a signed floating point number together with the corresponding unit (sccm for mass flow, C for temperature). In case of an overflow, the output shows oF. Pins and Digital Interface T x D R x D S C K M IS O M O S I /C S V D D G N D A S F 1 4 0 0 2 Figure 6: ASF1400 pin out. GND and VDD (Power Supply) The ASF1400 requires a voltage supply of between 7 V and 18 V. Since this voltage is internally regulated, there are no stringent requirements as far as ripple and stability are concerned. 2.1 Connector You need an EDAC 395-010-520-102 connector to connect the sensor. Please check the EDAC homepage for details (www.edac.net). Alternatively the AVX 00 6338 020 000 04 0 or AVX 00 6338 020 000 04 2 connectors can be used to connect the ASP1400 as well. (See www.farnell.com, order codes 635789 or 635730). 2.2 RS-232 Interface All configurations (see also Section 3) for the ASF1400 can be set using its RS-232 interface). To communicate with the ASF1400 via RS-232 the following pins are required: RxD (Receiving Data Line) TxD GND (Transmitting Data Line) (Ground) 2.3 Serial Peripheral Interface (SPI) The in earlier versions available SPI interface is due to changes in electronic components no longer supported. 3 Configuration and Commands The ASF1400 device accepts a set of commands through its RS-232 interface (see table 3 for valid commands; for correct settings of the RS-232 refer to Section 2.1).This allows the user to configure the ASF1400 device. Since the configuration is stored in the internal EEPROM, it is maintained after power breaks. With the exception of the stop s command, all commands have to be terminated by the return key (↵, ASCII #10 or #13). After completion of a command, the ASF1400 returns ok and is ready to take a new instruction. Before entering a command, it may be necessary to clear the buffer by means of using ↵. There is a trade-off between resolution and measurement time. Possible settings are listed in Table 2. Choosing 12 bit results in a measurement interval of 142 ms. With the max resolution of 15.2 bit, a new measurement is provided every 1280 ms. For faster sampling rates refer to the ASF1430 high speed mass flow meter device data sheet. Table 2: Resolution settings using the res=value command and corresponding response times res= The RS-232 of the ASF1400 is configured as follows: Baudrate 9600 Data Bits 8 Stop Bits 1 Parity none Protocol none 1 2 3 4 5 6 7 8 9 With these settings, the ASF1400 device can be connected to any PC or PDA equipped with terminal software. Resolution [bit] 12.0 13.0 13.5 14.0 14.3 14.6 14.8 15.0 15.2 data interval [ms] 142 284 427 569 711 853 995 1138 1280 Table 3: Commands of the ASF1400 device. Command help↵ www.sensirion.com Output commands Description Lists all available commands Version 2.2 5/9 ASF1400 Bidirectional Mass Flow Meter ver↵ get↵ go↵ s reset↵ res=1..9↵ res? mod=F | T↵ mod? Disp=s,d Disp? defspi=P | G↵ version stop resolution resolution mode mode display mode display mode define spi Provides type of sensor, software, hardware and customer version Start single measurement Starts series of measurements Stops series of measurements Resets ASF1400 device Sets resolution: 1 -> 12 bits; 9 -> 15 bits, see Table 2 Shows actual setting Selects Flow- (F) or Temperature mode (T) Shows actual setting Shows Flow (s) or Flow+Temperature (d) *no effect in the Temerature mode Shows actual setting Sets SPI in Push- (P) or Get mode (G), see also Section 4.3 Notes: • • • • 4 Default settings are marked in bold letters The commands are not case sensitive. In order to send a new command to the ASF1400 make sure the ASF1400 is not in measurement mode. Issue therefore a stop command s first. After this, any instruction can be given to the ASF1400 and a new series of measurement can be started by go↵. Due to the limited write cycles allowed for the EEPROM, excessive configuration modifications should be avoided. Specifications ASF1400 4.1 Absolute Maximum Ratings Ambient storage temperature Ambient operating temperature Overpressure resistance -65°C to 150°C 0°C to 70°C 2.0 bar 4.2 Electrical Specifications Table 3: ASF1400 DC Characteristics. Parameter Power Supply DC Operating Current Power Dissipation Conditions DC VDD = 9 V, no load VDD = 9 V, 3kΩ at RS232 output VDD = 9 V, no load Min. 7 Typ. 9 20 27 180 Max. 18 Units V mA mA mW Min. Typ. Max. Units ±5 ±9 V ±18 Ω mA Table 4: ASF1400 RS-232 Characteristics. Parameter RS232 Output Output Voltage Swing Conditions Transmitter output loaded with 3kΩ Power-Off Output Resistance Output Short Circuit Current RS-232 Input Voltage Range Voltage Threshold Low High Hysteresis Resistance www.sensirion.com 300 -15 0.8 0.2 3 Version 2.2 1.2 1.7 0.5 5 15 V 2.4 1.0 7 V V V kΩ 6/9 ASF1400 Bidirectional Mass Flow Meter 5 Physical Dimensions and Mounting Information The ASF1400 is mounted in chemically inert PBT housing. The rugged package has been designed to withstand overpressures of up to 2 bars. Higher pressure packages of up to 10 bars are available on request. Physical dimensions and mounting information are provided in Figure 11 and Table 6.  holes for ∅ 3 mm screws 8! nozzles for ∅ 6 mm rubber hose.   1 h  of the ASF1400  Table 6: Physical Dimensions device. Length Width Height Distance Diameter Pitch Pitch Pitch Pitch  L  W    h  D   d  s H G N  45.0 mm 40.0  mm 15.5 mm 25.2  mm 5.0 mm 2.54 mm 20.6 mm  29.1 mm 10.0 mm  " Holes for # PT® screws (∅ 2.2 mm, screw in not more than 4.4 mm)  Figure 11: Physical dimensions and mounting information of the ASF1400. 6 Ordering Information For small ordering quantities the ASF1400 sensor can be ordered directly at Farnell on http://www.farnell.com. Farnell is a worldwide distributor of electrical, electronic and industrial component products. When ordering ASF1400 series devices at SENSIRION please refer to the following part numbers. For the latest product information access SENSIRION’s website on http://www.sensirion.com Calibrated for Gas Type Air Range ± 400 sccm Packaging 2 bar Type ASF1400 Notes: ƒ Packages to sustain common mode pressures of 10 bars are available on request. ƒ Special electrical interfaces such as 4-20 mA output or others are available on request. ƒ For faster response times refer to the ASF1430 data sheet. ƒ A evaluation kit including ASF1400 devices, evaluation software and other accessories such a bypass, rubber hose and cables can be ordered. For detailed information check out the description of the Mass Flow Meter Evaluation Kit EK-F1 on http://www.sensirion.com www.sensirion.com Version 2.2 7/9 ASF1400 Bidirectional Mass Flow Meter Important Notices Warning, personal injury Do not use this product as safety or emergency stop devices or in any other application where failure of the product could result in personal injury. Do not use this product for applications other than its intended and authorized use. Before installing, handling, using or servicing this product, please consult the data sheet and application notes. Failure to comply with these instructions could result in death or serious injury. If the Buyer shall purchase or use SENSIRION products for any unintended or unauthorized application, Buyer shall defend, indemnify and hold harmless SENSIRION and its officers, employees, subsidiaries, affiliates and distributors against all claims, costs, damages and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if SENSIRION shall be allegedly negligent with respect to the design or the manufacture of the product. ESD Precautions The inherent design of this component causes it to be sensitive to electrostatic discharge (ESD). To prevent ESD-induced damage and/or degradation, take customary and statutory ESD precautions when handling this product. See application note “ESD, Latchup and EMC” for more information. Warranty SENSIRION warrants solely to the original purchaser of this product for a period of 12 months (one year) from the date of delivery that this product shall be of the quality, material and workmanship defined in SENSIRION’s published specifications of the product. Within such period, if proven to be defective, SENSIRION shall repair and/or replace this product, in SENSIRION’s discretion, free of charge to the Buyer, provided that: • notice in writing describing the defects shall be given to SENSIRION within fourteen (14) days after their appearance; • such defects shall be found, to SENSIRION’s reasonable satisfaction, to have arisen from SENSIRION’s faulty design, material, or workmanship; www.sensirion.com • the defective product shall be returned to SENSIRION’s factory at the Buyer’s expense; and • the warranty period for any repaired or replaced product shall be limited to the unexpired portion of the original period. This warranty does not apply to any equipment which has not been installed and used within the specifications recommended by SENSIRION for the intended and proper use of the equipment. EXCEPT FOR THE WARRANTIES EXPRESSLY SET FORTH HEREIN, SENSIRION MAKES NO WARRANTIES, EITHER EXPRESS OR IMPLIED, WITH RESPECT TO THE PRODUCT. ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION, WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE EXPRESSLY EXCLUDED AND DECLINED. SENSIRION is only liable for defects of this product arising under the conditions of operation provided for in the data sheet and proper use of the goods. SENSIRION explicitly disclaims all warranties, express or implied, for any period during which the goods are operated or stored not in accordance with the technical specifications. SENSIRION does not assume any liability arising out of any application or use of any product or circuit and specifically disclaims any and all liability, including without limitation consequential or incidental damages. All operating parameters, including without limitation recommended parameters, must be validated for each customer’s applications by customer’s technical experts. Recommended parameters can and do vary in different applications. SENSIRION reserves the right, without further notice, (i) to change the product specifications and/or the information in this document and (ii) to improve reliability, functions and design of this product. Copyright© 2001-2008, SENSIRION. CMOSens® is a trademark of Sensirion All rights reserved RoHS and WEEE Statement The SDP6x0 family complies with requirements of the following directives: • EU Directive 2002/96/EC on waste electrical and electronic equipment (WEEE), OJ13.02.2003; esp. its Article 6 (1) with Annex II. • EU Directive 2002/95/EC on the restriction of the use of certain hazardous substances in electricaland electronic equipment (RoHS), OJ 13.02.2003; esp. its Article 4. Version 2.2 8/9 ASF1400 Bidirectional Mass Flow Meter Revision history Table 1: Revision history Date Version Page(s) Changes Dec. 2001 May 2005 November 2008 Preliminary V2.1 V2.2 all all all First public release Specifications, typos, various small modifications SPI interface no longer supported ,overpressure resistance changed, new ISO-Logo, sales Office Information, introduction of revision history, new disclaimer, RoHS compliance Headquarters and Sales Office Sensirion AG Laubisruetistrasse 50 CH-8712 Staefa ZH Switzerland Phone: Fax: e-mail: Web: + 41 44 306 40 00 + 41 44 306 40 30 info@sensirion.com www.sensirion.com Sales Office USA (for North American customers only) SENSIRION Inc Westlake Pl. Ctr. I, suite 204 2801 Townsgate Road Westlake Village, CA 91361 USA Phone: Fax: e-mail: Web: +1 805-409 4900 +1 805-435 0467 michael.karst@sensirion.com www.sensirion.com Sales Office Korea (for Korean customers only) Sensirion Korea Co. Ltd. #1414, Anyang Construction Twr B/D 1112-1, Bisan-dong, Anyang-city Gyeonggi-Province, South Korea Phone: Fax: e-mail: Web: +82 31-440-9925~27 +82 31-440-9927 info@sensirion.co.kr www.sensirion.co.kr Sales Office Japan (for Japanese customers only) Sensirion Japan Co. Ltd Tel : Representative Director: Keiichi Hasegawa Fax: Shinagawa Station Bldg. 7F, 4-23-5, Takanawa, e-mail: Minato-ku, Tokyo, Japan Web: www.sensirion.com +81 3-3444-4940 +81 3-3444-4939 info@sensirion.co.jp www.sensirion.co.jp Version 2.2 9/9