MVI56-DFCM PROSOFT

Model: MVI56-DFCM
Brand: ProSoft Technology
Series: ControlLogix Platform (MVI56)
Core Function: Connects ControlLogix processors to DF1 serial devices via the backplane
Type: Communication Module (Single-slot)
Key Specs: 2 RS-232/422/485 Ports, DF1 Protocol, 5,000-word Database
Condition: New Original (New Surplus), not refurbished

As a senior controls engineer, I’ve found the ProSoft MVI56-DFCM to be the standard solution for integrating legacy DF1 devices—like SLC 500s, MicroLogix, or older weigh scales—directly into a modern ControlLogix chassis. It eliminates the need for external serial-to-Ethernet converters, reducing points of failure by living directly on the 1756 backplane.

The module treats the two serial ports as independent entities, allowing you to run one port as a Master and the other as a Slave. With its 5,000-word database, the MVI56-DFCM handles heavy data mapping tasks that would otherwise bog down the ControlLogix processor’s native serial port or bridge capacity.

Key Selling Points & Differentiators

Multi-Protocol Versatility: Each port is independently configurable for RS-232, RS-422, or RS-485, providing a “Swiss Army Knife” for legacy serial networking.
Large Command Capacity: Supports up to 100 user-defined commands per port, allowing for complex polling sequences of distributed serial nodes.
Tested Functional Stability: Every unit is verified on a 1756-A7 test rack, ensuring the internal battery is healthy and the backplane communication stays within the 800 mA power budget.
Not Recommended For: Applications requiring synchronized real-time motion control; serial protocols like DF1 introduce inherent latency unsuitable for <50 ms loops.
Rockwell Encompass Referenced: Fully compatible with Studio 5000/RSLogix 5000 using standard Sample Code or Add-On Instructions (AOI).