This is a fairly typical Control Panel. All control panels have been built and labeled per UL standards.
The top row of this picture shows 5 stepping motor drivers.
Towards the bottom of the cabinet is the Programmable Logic Controller, PLC with a PLC expansion module.
Several brands of PLC's have been used over the years. GE, AB, Keyence, Mitsubishi are just a few.
Something that may be of interest is the external air filter. This is a practice that has been used for several years now. The filters are a much higher quality and since they are on the outside of the control cabinet they are easy to change. Also, because the filters are visible they have been helpful in identifying when the cooling fans have failed, (since the filters remain cleaner then expected).
This project controlled some larger motors. To help keep the control and the power wiring separated two control boxes were used instead of one larger box. All of the higher voltage wiring and components are in the lower cabinet, while the more frequently accessed components are in the upper 120VAC cabinet.
Another point of interest is that incorporation of Ground Fault Circuit Interrupters, GFCI's. Twenty-four volt DC power supplies have also been used for sensors whenever possible. While neither of these are required by code, they have been standard practice for an additional level of safety.