Extend the Life of Your Remote I/O While Upgrading Your Head-End PLCs

It’s common for industrial applications to have older infrastructure equipment. You may think the only way to modernize is to replace the equipment — a big and costly endeavor that includes the following equipment:

  • The head-end processor that provides the logic and main control.
  • The remote IO where field devices are terminated with 4–20mA or fieldbus signals.
  • The network between the head-end PLCs and remote I/O.

Fortunately, you have another option that can help you reduce costs and downtime. It involves upgrading your head-end PLC and main processor, keeping your legacy remote I/O and field devices and then linking the new PLC and remote I/O with Phoenix Digital communications modules.

Recurring Hardware Issues
This is precisely what happened with a large, North American infrastructure company that wanted to extend the life of its existing network infrastructure. At the time, the company had new ControlLogix® PLC modules from Rockwell Automation installed on the head end, as well as legacy Rockwell PLC-5 Control Systems deployed in the field as the I/O. The company’s fiber network communications modules had been experiencing hardware issues, leading to frequent failure and resulting in significant downtime.

Replacing the Communications Modules
To solve these challenges, the company inserted a Phoenix Digital OCX fiber media converter into the newer ControlLogix PLC, and then inserted an OCM communication module into the legacy PLC-5. With these two modules in place, the newer ControlLogix PLC was able to communicate with the legacy PLC-5, extending the life of both the remote I/O and legacy equipment. Available as in-chassis or standalone units with DIN rail mounting, Phoenix Digital OCX and OCM modules can extend the life of legacy networks including ControlNet, Modbus, Data Highway and others. In this application, the OCX module functions as a fiber media converter, providing the company with a fault-tolerant and redundant communication network.

A Simple Way to Extend Legacy Network Life
By simply replacing the communications modules on the head-end PLC and in the PLC-5, the infrastructure company was able to bridge the gap between a modern head-end PLC and legacy remote I/O, successfully warding off obsolescence. This strategy works for any industrial application, from oil and gas to wastewater, and will help you extend the life of your existing PLCs.

To learn more, please visit the Phoenix Digital product page.


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