Which of the choices is not common for a PLC chassis?

In a PLC chassis, each component plays a specific role in the overall operation and structure of the system. The output slot is typically not referred to as a separate slot within the architecture of a PLC chassis. Instead, outputs are usually integrated into the output module, which is housed in the designated slots of the chassis.

An interface slot typically accommodates communication interfaces that allow the PLC to connect to other devices or systems. The PSU (Power Supply Unit) slot is vital for providing electrical power to the entire chassis. Communication slots support the various types of communication protocols necessary for data exchange between the PLC and other devices.

By understanding the roles of different types of slots in a PLC chassis, it's clear that while output capabilities are essential, they are not designated as a separate slot. Instead, they are part of the output module functionality within the chassis design.