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Series-641RM
Air Velocity Transmitter with Remote Heated Probe for HVAC and Clean Rooms
Models In Stock
- Output signal conditioning with digital filtering
- Install in tight spaces with compact design
- Easy setup with on-board buttons
Series-641RM
From
C$
1,061.74
Models In Stock
Product Overview
- Accuracy ± 3 %
- Accuracy Detail 3% FS process gas: 32 to 122°F (0 to 50°C); 4% FS process gas: -40 to 32°F and 122 to 212°F (-40 to 0°C and 50 to 100°C)
- Air Velocity, Max 15000 FPM
- Air Velocity, Min 250 FPM
- Cable Length 6 ft
- Electrical Connection Screw Terminal
- Electrical Output 4 to 20 mA
- Filter 0.5 to 15 s (Selectable)
- Loop Resistance 600 Ω max
- Media Compatibility Clean dry air / inert gas, Inert / non-reactive gases, Clean Dry Air, Helium, Nitrogen, Non-Corrosive Dry Gases
- Mounting Orientation None
- Number of Wires 4
- Operating Temperature, Max 140 °F
- Operating Temperature, Min 32 °F
- Output Detail 4 to 20 mA, isolated 24 V source, 3 or 4-wire connection
- Power Consumption 300 mA
- Pressure Limits Up to 100 psi
- Probe Diameter 0.3125 in
- Probe Length 12 in
- Process Temperature, Max 212 °F
- Process Temperature, Min -40 °F
- Relative Humidity Non-Condensing
- Response Time 1.5 s to 95%
- Response Time Note Flow: 1.5 s to 95% of final value (output filter set to minimum)
- Series ID Series-641RM
- Supply Power Note 12 to 35 Vdc, 10 to16 Vac. 1.5 A rating required on supply due to initial power surge drawn by transmitter
- Supply Power Type AC/DC
- Supply Voltage 10 to 16 Vac, 12 to 35 Vdc
Supported Applications
The Dwyer Series 641RM Air Velocity Transmitter utilizes heated mass flow sensor technology to measure air velocity in HVAC systems and clean rooms. The series is intended for use with clean, dry air and compatible, non-combustible gases.
Operating Conditions & Performance
The Series 641RM operates across a process temperature range of -40 to 212°F (-40 to 100°C) with an ambient operating temperature of 32 to 140°F (0 to 60°C). Humidity must be non-condensing. The transmitter supports measurement ranges from 250 FPM to 15,000 FPM and corresponding metric ranges from 1.25 MPS to 75 MPS.
Accuracy is specified as 3% FS for process gas temperatures between 32 to 122°F (0 to 50°C) and 4% FS for process gas temperatures of -40 to 32°F and 122 to 212°F (-40 to 0°C and 50 to 100°C). The response time is 1.5 s to 95% of final value with the output filter set to minimum; selectable filtering ranges from 0.5–15 seconds allow averaging in turbulent conditions.
The device withstands a maximum pressure limit of 100 psi (6.89 bar). Power requirements are 12-35 VDC or 10-16 VAC, with a supply rating of 1.5 A required due to the initial power surge drawn by the transmitter.
Configuration Options
The series offers configurable output and display options alongside specific mounting accessories:
- Output Signal: Isolated 4-20 mA with a 24 V source, supporting 3 or 4-wire connections. Maximum loop resistance is 600 Ω.
- Display Option: An optional field-upgradeable 1/2" 4-1/2 digit red LED display (Model 641-LED) provides local readout with a resolution of 1 FPM or 0.01 MPS (reduced to 10 FPM at the 10,000 and 15,000 FPM ranges).
- Probe Configuration: The standard probe features an overall length of 12" (30.48 cm) with a diameter of 5/16" (0.79 cm), connected to the electronic enclosure via a 6' (1.82 m) cable.
- Mounting Accessories: Available options include a universal mounting plate with 1/2” female NPT (Model A-156), a split flange mounting kit (Model A-158), and a duct mounting gland (Model A-159).
- Calibration Option: Units can be ordered with a suffix of -NIST for a NIST traceable calibration certificate.
The transmitter is not position sensitive, though the probe must be aligned with airflow direction indicated by dots on the sensor. Electrical connections are made via screw terminals.
Key Product Differences
The Series 641RM includes two primary model configurations:
- 641RM-12: Air velocity transmitter with a standard 6" cable connecting the probe to the enclosure.
- 641RM-12-LED: Includes the optional field-upgradeable LED display. This version weighs 13.9 oz (394.16 g) compared to the standard unit weight of 13.2 oz (374.26 g).
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