PLC CPU and IO Card Replacement

A PLC rack may have a damaged, or non functional component that needs replaced. A relay on an input or output card may be damaged by overdraw, or a CPU may suffer an electrical surge and be unable to operate its software.

A PLC in our systems is an assembly of a PLC CPU, and one more more component cards that handle inputs, outputs, or a mixture of these. The PLC CPU is the "brain" of the system and is what hosts the programming logic for the controller. Some PLC blocks are "remote" racks, in that its "CPU" is an interface module that is controlled by the primary PLC CPU where its programming logic is hosted. These systems will also have a remote rack network.

Cleereman Troubleshooting, PLC CPU and IO Card Replacement.mov

Disassembly and reassembly of a PLC rack Procedure

If not replacing the PLC CPU, ensure the CPU battery has power before turning off, or unplugging. Its retained values will be lost otherwise.
Turn off power to the PLC before
If replacing an input or output component, open the termination block cover and remove it.
To disassemble, pull the top gray tab to disconnect the card to be replaced from its neighboring cards. Each card connect to the one to its left.
Slide off the din rail, or pull the bottom din rail tab to remove it from the rack.

Attach the replacement component to the din rail in its desired position and connect it to its neighboring cards.
- If an input or output card insert the previously removed termination block with I/O wiring.
Once assembled, turn power back on to the PLC rack, and ensure the CPU switch is in the RUN position, and that the green run light is on.
- If replacing the PLC CPU, the Cleereman Technician likely per-loaded the correct PLC program onto the card before shipping for replacement. If not, let them know it has been replaced, ensure the network it is on has connection to the internet through the Stridelinx connection terminal, and let your Cleereman Technician know it is ready for them to upload the PLC software, and verify functionality.

This Video is relevant if...

A PLC component in one of your systems PLC racks is damaged or non functional.
A Cleereman Technician notified you that a PLC component needs to be replaced

Next Steps if issues persist

Verify termination block wiring on Input/Output cards
- Verify neutral/power wiring on each input/output card block (C1/C2).
Check PLC Ethernet communication to the main network
If a remote rack is attached, verify Ethernet communication cables on the remote rack network.

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