WTA Series Mass flow sensors for gases FEATURES · Flow ranges from 2 to 50 slpm, · Thermal mass flow sensing · 0.5...4.5 V non-ratiometric linear output · RoHS and REACH compliant · Quality Management System according to ISO 13485:2003 and ISO 9001:2008 MEDIA COMPATIBILITY To be used with dry gases only. The WTA series is NOT designed for liquid flow and will be damaged by liquid flow through the sensor. SPECIFICATIONS6 ELECTRICAL CONNECTION Maximum ratings 12345 Supply voltage Temperature limits Compensated Operating Storage Flow change Pressure drop Common mode pressure Humidity limits (non-condensing) 5 ... 28 V 0 ... 50 °C -25 ... 85 °C -40 ... 125 °C 5 slpm/sec 1.8 mbar @ 5 slpm 6 mbar @ 50 slpm 5 bar 0 ... 95 %RH 1 Vibration 20 g Mechanical shock2 30 g E / 11351 / G Pin 1 2 3 4 5 Connection Wire colour I / C* Blue +Vs Green +Vout Red GND Black I / C* Yellow * Internal connection. Do not connect for any reason. 1/4 www.first-sensor.com www.sensortechnics.com WTA Series Mass flow sensors for gases PERFORMANCE CHARACTERISTICS6 (VS = 12 ±0.01 V, TA = 20 °C, PAbs= 101.325 kPa, output signal is non-ratiometric to VS, media = air) Characteristics Zero offset Full scale span5 Full scale output Accuracy3 Min. Typ. Max. Unit 0.49 3.91 0.50 4.00 4.50 0.51 4.09 V ±(2 % of reading + 0.25 %FSO) ±(4.0 % of reading + 0.25 %FSO) Total accuracy (0...50 °C)4 Repeatability (incl. hysteresis) Offset long term stability (1 year) Noise level Current consumption (no load) Response time (t90) Warm-up time7 ±0.25 ±0.05 % of reading 0.1 15 10 70 %FSS mA ms Note: The sensor’s performance is determined by intake flow conditions which depend on mounting and environmental effects. To ensure laminar flow through the sensor, it should be considered to insert a straight tube with a length 10 times the inner diameter of the pneumatic connector or a laminar flow element upstream of the sensor. Additionally, the WTA has to be mounted with both ports horizontally and in an upright position. GAS CORRECTION FACTORS8 Gas type Ai r Oxygen (O2) Nitrogen (N2) Argon (Ar) Hydrogen (H2) Carbon dioxide (CO2) Gas correction factor 1.0 1.0 1.0 1.18 * 0.67 * For Hydrogen applications, the actual H2 calibration is performed whenever possible. Specification notes: 1. 2. 3. 4. 5. 6. 7. 8. Sweep 20 to 2000 Hz, 8 min, 4 cycles per axis, MIL-STD-883J w/CHANGE 4, Method 2007.3. 5 shocks, 3 axes, MIL-STD-883J w/CHANGE 4, Method 2002.5. Accuracy is the combined error from offset and span calibration, linearity, hysteresis and repeatability. Total accuracy is the combined error from offset and span calibration, linearity, hysteresis, repeatability and temperature effects. Full Scale Span (FSS) is the algebraic difference between the output signal for the highest and lowest specified flow. Specification is preliminary. Data sheet is based on Pre-Series sample verification. Warm-up time is the time from power on to the first stable reading. To obtain the real flow rates in a specific gas, multiply the readings from the sensor by the gas correction factor in the table. The factors are approximate and should be used as guidelines only. Sensor performance strongly depends on gas dynamics and has to be evaluated in the respective application. E / 11351 / G 2/4 www.first-sensor.com www.sensortechnics.com WTA Series Mass flow sensors for gases OUTLINE DRAWING first angle projection weight approx. 60 g S en so r dimensions in mm Connection L D Flow ranges up to 5 slpm ID=4 mm 84 mm Ø 4 mm Flow ranges from 10 slpm ID=8 mm 91 mm Ø 8 mm E / 11351 / G Note: Positive flow direction is defined by the molded-in arrow and results in positive output. 3/4 www.first-sensor.com www.sensortechnics.com WTA Series Mass flow sensors for gases ACCESSORY (included in delivery) Connecting cable assembly dimensions in mm ORDERING INFORMATION Series Options WTA Flow range L 002 L 003 L 004 L 005 L 010 L 020 L 030 L 040 L 050 2 3 4 5 10 20 30 40 50 slpm slpm slpm slpm slpm slpm slpm slpm slpm Gas D* Dry air Flow direction U Unidirectional Grade P Prime * other calibration gases on request Example: WTA L 005 D U P First Sensor reserves the right to make changes to any products herein. First Sensor does not assume any liability arising out of the application or use of any product or circuit described herein, neither does it convey any license under its patent rights nor the rights of others. E / 11351 / G 4/4 www.first-sensor.com www.sensortechnics.com