Model 641B Air Velocity Transmitter
Brand: Dwyer Instruments, LLCThe Model 641B Air Velocity Transmitter uses a heated mass flow sensor suitable for dirty air flow applications.
A Low-Cost, Direct Reading Instrument Used for Both Air Velocity & Static Pressure Tests.
It has user-selectable ranges from 250 FPM (1.25 MPS) to 2000 FPM (10 MPS).
Features- SS Sensor Suitable for Dirty Air Flow Measurement
 - Ranges from 250 FPM (1.25 MPS) to 2,000 FPM (10 MPS)
 - 4 to 20 mA Output
 - Digital Filter for Signal Damping
 
Specifications
Accuracy
- 5 % of Full Scale Process Gas: 0° to 50° C (32° to 122° F)
 - 6 % Full Process Gas: -40° to 0° C & 50° to 80° C (-40° to 32° F & 122° to 176° F)
 
Ambient Temperature Range
- 0° to 60° C (32° to 140° F)
 
Consumption
- 300 mA - Max.
 
Electrical Connectors
- Screw Terminal
 
Environmental Protection
- IP66
 - NEMA 4X
 
Loop Resistance
- 600 ohms, Max.
 
Media
- Compatible Air
 - Non-Combustible Gases
 
NPT Connection
- 1/2" NPT Female
 - 1/2" NPT Male
 
Output
- 4-20 mA Isolated 24 V Source, 3 or 4-Wire Connection
 
Power Requirement
- 10-16 Vac
 - 12-35 Vdc
 
Process Temperature
- -40° to 80° C (-40° to 176° F)
 
Response Time
- 0.5 to 15 seconds
 - 1.5 seconds to 95 % of Final Value
 
- Exhaust stack flow monitoring
 - Air control in drying processes
 - HVAC air velocity measurements
 - Fan supply and exhaust tracking
 - Clean room ventilation monitoring