A rack or chassis is a hardware assembly that helps in housing the processor, communication and input-output modules.
It works in the following ways:
- It distributes the power evenly
- It contains the different input and output modules.
- It acts as a communication link between I/O module and the CPU.
In different PLC systems, there are many different slots for chassis that are available. If a user wants additional chassis they can be connected by using chassis interconnecting cables.