Product Overview
The Allen-Bradley 1771-CFM is a configurable flow meter module designed for the PLC-5 series from Rockwell Automation. This specialized I/O module interfaces directly with turbine flowmeters, magnetic pickups, and single-channel shaft encoders, enabling fast and accurate flow or shaft speed calculation. It simplifies ladder logic programming and conserves PLC memory, making it a direct replacement for 1771-QRC and 1771-QRD modules without requiring logic changes.
Technical Specifications Breakdown
Key parameters for the 1771-CFM are listed below for quick reference:
| Feature | Specification |
|---|---|
| Module Type | Specialized I/O Module |
| Number of Inputs | 4 Digital: Magnetic Pickup 50 mV-200 V AC Peak, TTL-Compatible 4-40 V DC, Proximity Pickups Bently 3300 5 & 8 mm |
| Number of Outputs | 4 Digital: 5-40 V DC (Supplied by User) |
| Backplane Current | 1.0 Amps max |
| Module Scan Time | 1.3-5 ms |
| Storage Temperature | -40-185 F (-40-85 C) |
| Weight | 1.9 lbs (0.9 kg) |
| Dimensions | 3.5 x 6.5 x 2.0 in (89 x 165 x 51 mm) |
| Coating | Conformal Coat |
Industry Applications
For example, in a gas metering station, the 1771-CFM processes signals from turbine flowmeters to calculate totalized flow, controlling up to four outputs based on preset thresholds. Its high-resolution frequency mode supports precise speed monitoring in rotating machinery, reducing downtime by providing real-time diagnostics.
Installation & Setup Guidance
Mount the 1771-CFM in a single slot of a PLC-5 chassis. Use the 1771-WN wiring arm for secure connections. Ensure user-supplied 5-40 V DC power is available for digital outputs. Configure the module via the PLC processor: select from non-resettable totalizer, totalizer, high-resolution frequency, or direction sensor modes. The maximum input frequency is 100 kHz, and the maximum count value range is 0 to 9,999,999 (programmable). Verify backplane current does not exceed 1.0 Amp.
Maintenance & Reliability
The conformal coating protects against moisture and contaminants. Operate the module within 0 to 60 degrees Celsius (32 to 140 degrees Fahrenheit) for reliable performance. Inspect wiring connections and the 1771-WN arm periodically for signs of wear. The module sends diagnostic information to the PLC processor in a configuration block, aiding proactive maintenance.
Compatibility & Integration
The 1771-CFM is fully compatible with Allen-Bradley PLC-5 systems. It supports magnetic pickups (Bently 3300 proximity pickups) and TTL-compatible pulse sources. The module processes signals from turbine flowmeters or single-channel shaft encoders, integrating into existing automation architectures without ladder logic modifications.
Selection Guide & Purchasing Advice
When selecting the 1771-CFM, confirm your application requires 4 digital inputs and 4 digital outputs with magnetic pickup compatibility. Please verify current lifecycle status and availability with AutoDCSTech before ordering. AutoDCSTech offers genuine Allen-Bradley parts with expert support.
Troubleshooting & Common Issues
If outputs do not activate, check the user-supplied 5-40 V DC power source. For erratic readings, verify input signal levels: magnetic pickups require 50 mV-200 V AC peak, while TTL signals need 4-40 V DC. Confirm the module scan time (1.3-5 ms) aligns with process requirements. Use diagnostic words in the configuration block to identify configuration errors.
Availability & Condition at AutoDCSTech
| Part Number | 1771-CFM |
|---|---|
| Availability | In Stock |
| Condition | New |
| Warranty | One Year |
| Origin | US |
