TechTalk – Rockwell : PLC And Slot Numbers

Slot numbering for Allen Bradley PLC are fundamentally important to identify where your cards are on the back-panel.

Here are picture of PLC that identifies how the slot numbers are allocated.

Allen Bradley-Rockwell ControlLogix
Starts with slot zero (which is normally CPU) and so on. Power supply does not have slot number.
Xybernetics Rockwell - PLC And Slot Numbers

The picture below shows with CPU in slot zero and EtherNet/IP card in slot 1
Xybernetics Rockwell - PLC And Slot Numbers

Allen Bradley-Rockwell PLC-5
Same as ConroLogix, starts with slot zero (which is normally CPU) and so on. But for PLC-5 it is identified as C0, C1, C2 and so on.
Xybernetics Rockwell - PLC And Slot Numbers

The picture below shows with CPU in slot zero (C0) and power supply in slot 3 (C3)
Xybernetics Rockwell - PLC And Slot Numbers

Allen Bradley-Rockwell SLC
The first slot is for CPU (as indicated in the picture below) and the rest if for I/O card.
Xybernetics Rockwell - PLC And Slot Numbers

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