Allen-Bradley 1771-CFM | Configurable Flow Meter I/O Module

Overview

The 1771-CFM from Allen-Bradley is a configurable flow meter module designed for PLC-5 systems. It provides four digital inputs and four digital outputs operating at 5–40 VDC, supporting accurate flow measurement and shaft speed calculation. Its compact design measures 3.5 × 6.5 × 2.0 inches and weighs 1.9 pounds.

Compatibility

The 1771-CFM interfaces with turbine flowmeters, magnetic pickups, and single-channel shaft encoders. It also accepts TTL pulse sources, allowing versatile integration into industrial automation systems. This module directly replaces 1771-QRC and 1771-QRD modules without modifying ladder logic.

Electrical Specifications

The 1771-CFM supports magnetic pickup inputs from 50 mV–200 V AC peak, TTL-compatible 4–40 V DC, and proximity pickups like Bently 3300 (5 & 8 mm). It draws a maximum backplane current of 1.0 Amps and provides scan times between 1.3–5 ms. The module is conformally coated for durability.

Physical Specifications

The 1771-CFM mounts in a single slot and uses a 1771-WN wiring arm for organized connections. Its storage temperature ranges from -40°F to 185°F (-40°C to 85°C). The module’s compact footprint facilitates installation in PLC-5 racks while maintaining easy access for maintenance.

Functionality

The 1771-CFM calculates flow signals from field devices in real time, reducing PLC memory usage. It supports diverse applications in power generation, oil and gas, automotive, food and beverage, and pipeline industries. Its high reliability and flexible configuration make it ideal for both new and retrofit PLC installations.