The PLC control cabinet generally includes the following five parts:
Air Switch
A general air switch, which is the power control for the entire cabinet. Believe that every cabinet must have something.
PLC
This should be selected according to the needs of the project. For example, if the project is small, it can be directly an integrated PLC, but if the project is large, it may require modules, card type, and redundancy (that is, two sets of alternating use).
power supply
A 24VDC switching power supply, most PLCs come with a built-in 24VDC power supply, and whether to use this switching power supply depends on whether it is truly needed.
relay
Generally, PLCs can directly send instructions to the control circuit, but they may also be relayed by relays first. For example, if the output port of your PLC is powered by 24VDC, but the diagram in your control circuit requires the PLC to supply 220VAC nodes, then you must add a relay to the PLC output port. That is, when the command is issued, the relay will act, but then connect the nodes of the control circuit to the normally open or normally closed points of the relay. It also depends on the situation to choose whether to use a relay.
connecting terminal
This is definitely an essential item for every cabinet and can be configured based on the number of signals. If it's just a simple PLC control cabinet, you basically need these things. If you need other things inside your control cabinet, it depends on the situation. For example, if you need to supply power to certain on-site instruments or small control boxes, you may need to increase the number of air switches. Or if you want the PLC to be connected to the upper computer, you may need to add a switch or something. It depends on the situation.

The PLC control cabinet can complete equipment automation and process automation control, achieve perfect network functions, and has the characteristics of stable performance, scalability, and strong anti-interference. It is the core and soul of modern industry. PLC control cabinets, frequency conversion cabinets, etc. can be customized according to user needs to meet their requirements, and can be paired with human-machine interface touch screens to achieve easy operation. The equipment can also transmit data through communication protocols such as Modbus and Profibus with the DCS bus upper computer; Control and monitoring implemented by industrial computers, Ethernet, etc.
Power supply: DC 24V,
Single phase AC 220V,
（-10%，+15%），50HZ
Protection level: IP41 or IP20
Environmental conditions: The ambient temperature ranges from 0 ℃ to 55 ℃,
Prevent direct sunlight exposure; The relative humidity of the air should be less than 85% (without condensation). Stay away from strong vibration sources and prevent frequent or continuous vibrations with a frequency of 10-55HZ. Avoid corrosive and flammable gases.

• Smart industrial control
• Low voltage distribution system
• Operation and maintenance management system of Internet of things