Redundant fiber ControlLogix in-chassis Ethernet networking modules for PLCs and Ethernet field devices

Multi-fault tolerant, Ethernet communications built for industrial ControlLogix PLC applications

The OCX fiber Ethernet networking module is not an IT switch.  The ControlLogix in-chassis OCX module is an OT (operational technology) networking module that is built for critical industrial Ethernet applications and networking together Ethernet PLCs.

Industrial applications for Ethernet networking are different from IT applications.  If a networking module fails, it needs to be hot swappable and plug and play, not complicated with command line interface programming; and taking minutes for boot up is not acceptable on the plant floor after power cycle.

An industrial Ethernet module needs to be able to transport multiple industrial Ethernet protocols, at the same time -- for example Ethernet/IP, PROFINET, and Modbus TCP, and have options for other industrial protocols such as ControlNet, Data Highway, IEC 61850, R/IO, GE Genius, RS-232, RS-485, RS-422, CTI, Siemens, Texas Instruments Remote I/O, and Modbus Serial.

And, it needs to be compatible with any vendors PLCs or DCS.

That's exactly what the Phoenix Digital fiber Ethernet networking modules provide, and they are available as DIN rail mount, ControlLogix in-chassis modules and PLC-5 in-chassis modules.

The OCX module is a ControlLogix in-chassis Ethernet module that is engineered specifically for the 1756 ControlLogix platform. The OCX module supports Ethernet, ControlNet, Data Highway, and Modbus RTU. The OCX module is 1756-RM2 and 1756-SRM redundancy module compliant to reside in the processor chassis. The OCX is available as an in-chassis module or as a standalone panel mount.


Built-for control engineers

  • ControlLogix in-chassis PLC module
  • No command line interface configuration
  • Plug and play, hot swapable
  • 10-second power-up
  • Transports multiple industrial protocols at the same time

Built-for critical networks

  • Redundant fiber between OCR modules
  • Fiber facilitates long distances, eliminates ground loop issues, and impervious to EMI
  • Copper Ethernet to PLCs and field devices
  • 0 second network convergence time if a fiber fails or a module fails

Technical Data

Technical Data
Specifications Fiber Optic Type
Mating Connector
Transmit Launch Power

Receive Sensitivity
Single Mode or Multimode
ST, SC, or LC
-15 dBm (Typical Multimode; -18 dBm (Single Mode)
-32 dBm
Single Mode or Multimode
-15 dBm (Typical Multimode; -18 dBm (Single Mode)
-32 dBm
Protocol Ethernet Speed 10/100 Ethernet (All versions) 10/100/1000 Ethernet (All versions)
Power Supply Plug-In Modules (Typical) +5 VDC, 1.5 to 1.8 Amps +5 VDC, 1.5 to 1.8 Amps
Environmental Operating Temperature
Storage Temperature
Relative Humidity
0° to 60° C (32° to 140° F)
-40° to 85° C (-40° to 185° F)
0 to 95% RH, noncondensing
0° to 60° C (32° to 140° F)
-40° to 85° C (-40° to 185° F)
0 to 95% RH, noncondensing
Dimensions OCX Module Single Slot, 1756 Chassis Single Slot, 1756 Chassis
Approval UL and UL/C
Class I, DIV 2, All Groups
Class I, DIV 2, All Groups

Order Information

Part Numbers  
OCX*-CTN-(1)-(2)-(3)-(4)-(5)-(6)-(7) ControlNet Communications
(1756 Plug-In and DIN Rail, Standalone modules)
* OCX modules are rated for use in Class I, Div 2 hazardous locations, when the “-D” diagnostic option is included.
(1) “85”
850 nanometer wavelength selection
1300 nanometer wavelength selection
1550 nanometer wavelength selection
(2) “P”
Panelmount, Standalone Enclosure  (OCM modules only)
DIN Rail, Standalone Enclosure (OCX modules only)
1771, 1746, or 1756 Plug-In Module
(3) “D”
Interactive Diagnostics (Required for OCX CL I, DIV 2
No Diagnostics
(4) “ST”
ST Fiber Optic Connector Style
SMA Fiber Optic Connector Style (Available with 850nm wavelength only.)
(5) “24V”
24 VDC Operation
120/220 VAC, 50/60 Hz Operation
125 VDC Operation
(6) “SM”
Singlemode Fiber Compatibility (Available with 1300 nm or 1550 nm Wavelengths, and ST connector options only.)
Multimode Fiber Compatibility
(7) “EXT” = Extended Capacity Operation (Required for networks with 28 or more OCM/OLC/OCX-CTN modules.)


Phoenix Digital network communications architecture

This video explains typical applications, types of devices connected, how the redundant fiber ring backbone is connected to each module, and what happens when a fiber or module breaks and what you have to do to repair the link.

Phoenix Digital networking diagnostic software

How to use the Phoenix Digital networking diagnostic software to troubleshoot modules or your network.

OCX Hardware Overview

This video covers fiber and copper connections, setup, power, LEDs, troubleshooting, trap/reset button, SFPs, dip switch settings, and RSS return signal strength.


Softing Inc.