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DF1 Master/Slave Network Interface Module for ControlLogix


Discontinued: No new product for sale. More Info
Recommended replacements: PLX51-DF1-ENI

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When needing additional DF1 ports in your ControlLogix system, the MVI56-DFCM Network Interface Module is the fastest and easiest way to add DF1 Half/Full Duplex Master and Slave capability. This module has two powerful and fully configurable DF1 ports allowing the many SCADA and field devices supporting the DF1 protocol to be integrated into the ControlLogix platform. Devices commonly supporting the protocol include Rockwell Automation PLCs and power monitoring equipment, as well as several other third party devices. Each port is user-configurable to act as a Master or as a slave.

Features and Benefits

The MVI56-DFCM (DF1 Communication Module) allows Allen-Bradley ControlLogix I/O compatible processors to interface easily with other DF1 protocol compatible devices. Compatible devices include not only Modicon PLCs (which all support the DF1 protocol) but also a wide assortment of end devices.

The module has two serial ports supporting the DF1 protocol, with each port user-configurable to act as a master or as a slave. Data transfer between the module and the ControlLogix processor is asynchronous to the DF1 network, with the module's internal database being used to exchange data between the processor and the DF1 network.


  •  Single Slot - 1756 backplane compatible
  •  Local or remote rack
  •  The module is recognized as an Input/Output module and has access to processor memory for data transfer between processor and module
  •  Ladder Logic is used for data transfer between module and processor.
  •  Configuration data obtained through user-defined ladder. Sample ladder file included

DF1 Master Protocol Specifications

The ports on the DF1 module can be individually configured as Master ports. When configured in master mode, the DFCM module is capable of reading and writing data to remote DF1 devices, enabling the processor to act as a SCADA sub-master.

  • Command List: Up to 100 commands per Master port, each fully-configurable for function, slave address, register to/from addressing and word/byte count
  • Status Data: Error codes available on an individual command basis. In addition, a slave status list is maintained per active master port
  • Polling of Command List: User-configurable polling of commands, including disabled, continuous, and on change of data (write only)

DF1 Slave Protocol Specifications

The module accepts DF1 commands from an attached DF1 master unit. When in slave mode, the module can accept DF1 commands from a master to read/write data stored in the module's internal registers. This data can be derived from other DF1 slave devices on the network through a master port or from the processor and is easily transferred to the processor's data registers.

Tested Hardware Connections

Several hardware connections have been tested by ProSoft Technology or have been customer field tested. The following physical connections have been tested successfully:

  • RA Panel view (Full Duplex point-point, DFCM as slave)
  • RA Processors (Full/Half duplex, DFCM as either master or slave)
  • RA Power Monitors (485 Half-Duplex DFCM as Master)




Backplane Current Load

800 mA @ 5.1 VDC
3 mA @ 24 VDC

Operating Temperature

32° F to 140° F (0° C to 60° C)

Storage Temperature

-40° F to 185° F (-40° C to 85° C)


30 g Operational
50 g non-operational


5 g from 10 to 150 Hz

Relative Humidity

5% to 95% (without condensation)

LED Indicators

Module Status
Backplane Transfer Status
Application Status
Serial Activity

Debug/Configuration port (CFG)

CFG Port (CFG)

RJ45 (DB-9M with supplied cable)
RS-232 only

Application ports (PRT1 & PRT2)

Full hardware handshaking control, providing radio, modem and multi-drop support

Software configurable communication parameters

Baud rate: 110 to 115,200 baud, depending on protocol

RS-232, 485 and 422

Parity: none, odd or even

Data bits: 5, 6, 7, or 8

Stop bits: 1 or 2

RTS on/off delay: 0 to 65535 milliseconds

App Ports (P1,P2) (Serial modules)

RJ45 (DB-9M with supplied cable)

RS-232 handshaking configurable

500 V Optical isolation from backplane

Shipped with Unit

RJ45 to DB-9M cables for each port

6-foot RS-232 configuration cable


Ex Certificate (ATEX Directive) 79.81 kB Last Modified 11/22/2019
CB Safety 41.99 kB Last Modified 02/26/2020
Declaration of Conformity (RoHS/CE) 301.57 kB Last Modified 03/04/2018
Country Approval - Russia - EAC Declaration (Wired) 1.92 MB Last Modified 01/07/2020
Korean KC Registration 616.34 kB Last Modified 03/13/2020
UL/cUL; Class 1, Div 2 1.12 MB Last Modified 02/27/2019
UL/cUL; Class 1, Div 2 (Canada) 1.14 MB Last Modified 02/27/2019