dwyer-inst.comDWYER INSTRUMENTS, INC.®T: 219-879-8000 | F: 219-872-9057 | info@dwyermail.com 800-872-9141FEATURES/BENEFITS• Field selectable ranges from 250 FPM (1.25 m/s) to 15,000 FPM (75 m/s) suit almost any application and reduces inventory• Optional bright LED display easily provides local indication• Easy push button set-up reduces installation time• Compact housing minimizes installation footprint• 4 to 20 mA output for use with most building management systems• Digital filter for signal dampingAPPLICATIONS• Exhaust stack flow monitoring• HVAC air velocity measurements• Clean room fresh air supply• Air control in drying processes• Fan Supply and exhaust tracking• Ensuring proper lab hood exhaust flow ratesDESCRIPTIONThe SERIES 641 Air Velocity Transmitter is the ideal instrument for monitoring air flow. This transmitter uses a heated mass flow sensor which allows for precise velocity measurements at various flow rates and temperatures. The 641’s 16 field selectable ranges provide it the versatility to be selected for several air flow applications. The optional LED produces a complete, cost effective solution for local indication of air flow.SPECIFICATIONS OPTIONAL DISPLAY VERSION SPECIFICATIONS Service Clean air and compatible, non-combustible gases.Field Selectable RangesFPM: 250, 500, 1000, 2000, 3000, 5000, 10000, 15000; m/s: 1/25, 2.5, 5, 10, 15, 25, 50, 75.Accuracy3% FS Process gas: 32 to 122°F (0 to 50°C); 4% Process gas: -40 to 32°F & 122 to 212°F (-40 to 0°C & 50 to 100°C).Response TimeFlow: 1.5 seconds to 95% of final value (output filter set to minimum).Temperature LimitsProcess: -40 to 212°F (-40 to 100°C); Ambient: 32 to 140°F (0 to 60°C).Pressure Limits100 psi (6.89 bar) maximum.Humidity LimitNon-condensing.Power Requirement12 to 35 VDC, 10 to 16 VAC. 1.5 A rating required on supply due to initial power surge drawn by transmitter.Output Signal4 to 20 mA, isolated 24 V source, 3 or 4 wire connection.Output FilterSelectable 0.5 to 15 (seconds)Loop Resistance600 Ω max.Current Consumption300 mA max.Electrical ConnectionsScrew terminal.Process Connections1/2˝ male NPT.Enclosure RatingDesigned to meet NEMA 4X (IP66) for non-LED models only.Mounting OrientationUnit not position sensitive. Probe must be aligned with airflow.Weight12.6 oz (357.2 g).Agency ApprovalsCE.Display4-1/2 digit 1/2˝ red LED.Resolution1 FPM, 0.01 MPS (10 FPM @ 10,000 and 15,000 FPM ranges).Weight13.3 oz (377 g).SERIES 641 | AIR VELOCITY TRANSMITTERImportant Notice: Dwyer Instruments, Inc. reserves the right to make changes to or discontinue any product or service identified in this publication without notice. Dwyer advises its customers to obtain the latest version of the relevant information to verify, before placing any orders, that the information being relied upon is current.®dwyer-inst.comDWYER INSTRUMENTS, INC.DS-641 Rev. 1 | 2/17T: 219-879-8000 | F: 219-872-9057 | info@dwyermail.com 800-872-9141DIMENSIONSWIRING DIAGRAMHOW TO ORDERSERIES641 - Air velocity transmitterPROBE LENGTH-6 - 6˝-12 - 12˝-18 - 18˝-24 - 24˝-30 - 30˝-36 - 36˝OPTIONS-AT - Aluminum tag-LED - LED display-NIST - NIST traceable calibration certificate-ST - Description641-6-ATUse the bold characters from the chart below to construct a product code.A-156A-158A-159ACCESSORIESModelDescriptionA-156A-158A-159641-LEDFlange mounting plate with 1/2" female NPTSplit flangeMounting gland with 1/2" male NPTField upgradeable LED641 AVT WITH DISPLAY OPTIONProbeA Dimension in [mm]B Dimension in [mm]6˝7-63/64 [202.80]9-13/16 [249.24]12˝13-63/64 [355.20]15-13/16 [401.64]18˝19-63/64 [507.60]21-13/16 [554.04]24˝26-63/64 [685.40]28-13/16 [731.84]30˝32-63/64 [837.80]34-13/16 [884.24]36˝37-63/64 [964.80]39-13/16 [1011.24]641 AVT WITHOUT DISPLAY OPTIONProbeA Dimension in [mm]B Dimension in [mm]6˝7-7/16 [188.91]9-9/32 [235.74]12˝13-7/16 [341.31]15-9/32 [388.14]18˝19-7/16 [493.71]21-9/32 [540.54]24˝26-7/16 [671.51]21-9/32 [540.54]30˝29-7/16 [747.71]34-9/32 [870.74]36˝37-7/16 [950.91]39-9/32 [997.74]4-29/64[113.11]1/2 NPT1/2-14 NPT13/16[20.64]B DIMENSIONA DIMENSION3-1/4[82.55]B DIMENSIONA DIMENSION2-23/32[29.06]4-29/64[113.11]1/2 NPT1/2-14 NPT25/32[19.84]POWER SUPPLYAC OR DCRECEIVER4-WIRE3-WIRERECEIVER NEGATIVECOMMONRECEIVERDC SUPPLYONLY(EITHERPOLARITY)3-WIRERECEIVER POSITIVECOMMONRECEIVERDC SUPPLYONLY(EITHERPOLARITY)Next >