Allen-Bradley 1771-CFMK Flowmeter Module 4 I/O

1771-CFMK Allen-Bradley PLC-5 Flow Meter I/O Module

Product Introduction

The 1771-CFMK from Allen-Bradley is a versatile configurable flowmeter module within the PLC 5 series. This module performs rate calculation and high-speed totalizing tasks with exceptional efficiency. Moreover, it interfaces seamlessly with magnetic pickup flowmeters, DC pulse sources, and proximity probes. This model offers broad processor compatibility, working with PLC-2, PLC-3, PLC-5, and PLC-5/250 families. Furthermore, the 1771-CFMK can operate in three distinct modes. It functions as a standard CFM module, or as a direct replacement for QRC or QRD modules. This flexibility makes it an ideal upgrade for legacy systems. Typical applications include automotive, food and beverage, power management, and oil/gas industries.

Input and Output Specifications

This flowmeter module accepts signals across four dedicated input channels. Each channel supports three distinct input types. First, it handles magnetic pickup signals from 50 mV to 200 V AC peak. Second, it accepts 4 to 40 V DC pulses with open collector (TTL-compatible) inputs. Third, it interfaces with proximity probes compatible with Bently Nevada 3300 transducer systems. Additionally, each input channel is field-configurable for either flowmeter input or gate input. For outputs, the 1771-CFMK provides four digital channels. These outputs feature a maximum on-state voltage drop calculated as 0.6 Ohms multiplied by the current. Leakage current stays below 300 microamps at 40 V DC, ensuring reliable switching performance.

Power and Thermal Characteristics

The 1771-CFMK draws a maximum backplane current of 1 Amp from the chassis. Its power dissipation ranges from 2 Watts at minimum to 13 Watts at maximum load. Consequently, thermal dissipation varies between 6.8 BTU/hour and 54.2 BTU/hour. This peak thermal dissipation of 54.2 BTU/hour requires adequate ventilation within the enclosure. Therefore, ensure proper airflow around the module during installation. The single-slot design minimizes chassis space usage while delivering robust functionality. For environmental resilience, the module operates reliably within 0 to 60 degrees Celsius. This temperature range covers most industrial control room environments.

Compatibility and Replacement Benefits

This module stands out due to its exceptional processor compatibility. It works with PLC-2, PLC-3, PLC-5, and PLC-5/250 processors that support block-transfer capabilities. Specifically, the 1771-CFMK interfaces between I/O devices and these controllers through block-transfer operations. As a replacement unit, it directly substitutes for 1771-QRC and 1771-QRD modules. This drop-in replacement capability minimizes system downtime during upgrades. Furthermore, existing ladder logic programs typically remain functional without modification. The module performs high-speed totalizing and rate calculations for turbine metering applications. Its maximum input frequency of 100 kHz supports demanding flow measurement scenarios.

Installation and Configuration Guidelines

Installing the 1771-CFMK follows standard PLC 5 chassis procedures. First, power down the chassis completely before module insertion. Next, select any available slot in the I/O chassis for installation. Slide the module firmly into place until the connectors seat properly. Secure it using the captive screws on the front panel. After physical installation, configure each input channel for its specific function. Choose between flowmeter input mode or gate input mode per channel. Additionally, select the desired operating mode during configuration. Options include standard CFM, QRC replacement, or QRD replacement modes. Always verify block-transfer settings in your PLC program for proper communication. Finally, test the module with actual field signals before placing the system online.

Packaging and Logistics

Each 1771-CFMK module is packaged with care for secure transit. The package includes the following items:

• One Allen-Bradley 1771-CFMK configurable flowmeter module

• Protective anti-static bag to prevent electrostatic damage

• Basic installation reference card with pinout information

All orders ship through premium global carriers. We utilize FedEx, UPS, and DHL for reliable, trackable delivery worldwide. Please inspect the module upon arrival for any signs of shipping damage.

Frequently Asked Questions (FAQ)

1. Which processors are compatible with the 1771-CFMK module?
This module works with PLC-2, PLC-3, PLC-5, and PLC-5/250 processors. All these controllers must support block-transfer operations for proper functionality.

2. Can this module replace an existing 1771-QRC or 1771-QRD unit?
Yes, the 1771-CFMK serves as a direct replacement for both 1771-QRC and 1771-QRD modules. You typically do not need to modify your existing ladder logic.

3. What types of input devices connect to this flowmeter module?
It accepts magnetic pickups (50 mV to 200 V AC), TTL-compatible DC pulses (4-40 V), and Bently Nevada 3300 proximity probes. Each of the 4 inputs is independently configurable.

4. What is the maximum input frequency supported by this module?
The 1771-CFMK handles input frequencies up to 100 kHz. This capability supports high-speed flowmeter and turbine metering applications effectively.

5. Which shipping carriers do you use for delivery?
We ship all orders via FedEx, UPS, or DHL. These carriers offer real-time tracking and global coverage for your peace of mind.