
Components of a Control Cabinet
Control cabinets are vertical enclosures with servo drives and other electromechanical components that control or monitor machinery and factory systems associated with it. The control cabinet is a stainless steel box, which can either be wall-mounted or a standalone module on the floor. Inside the control cabinet, there are many components from servo drives to PLCs and terminal blocks.
Power is typically supplied to the cabinet from the top portion. There is an AC power distribution system (PDS), associated with the main power breaker. The PDS, transfer power to all components that require AC power. Power Supplies convert AC to DC voltage, which is required for the performance of the majority of other components within the cabinet. The power supply will typically convert 480V or 120V AC to 24V DC as DC is generally regarded as a safer voltage to deal with inside the panel.
The converted DC voltage is passed on a DC power distribution system which further takes to other components. Another important component of the cabinet is the Ethernet switches. This helps in establishing a communication between the devices within the cabinet using a Cat5 or Cat6 cable. The radios process the data that comes from the control panel and transmits to other locations or machines which is far away from the control cabinet with the help of an industrial antenna. The radio is paired with a polyphaser that protects the internal panel hardware from lightning.
PLCs or programmable logic controllers are the brain of the control cabinet, about which we have discussed in detail in our earlier articles. The bottom rack of the cabinet contains terminal blocks that act as the connection point for the field instruments to interface with the control cabinet. Depending on the function, different signals, either analog or digital, are processed by the terminal blocks.
Then we have relays that control the digital outputs, which use a lower voltage signal to control the higher voltage circuits. These also protect the PLC from overcurrent. These components are attached to the control cabinet using DIN rails and also wire ducts that tidily arrange the numerous wiring, and together these are mounted onto a backplate that is separate from the enclosure.
An HMI (Human Machine Interface) mounted to the door of the cabinet enclosure allows us a way to view and interact with the data being collected by the PLC.
Amphenol ICC’s DIN 41612 and Millipacs® backplane connectors go inside the PLC and Quickie® IDC establishes a connection from the cabinet to the HMI. Industrial Ethernet connectors like ix Industrial™ and SPE along with VerIO™, RJ45, USB, and D-Sub serve the CPU, I/O, and communication modules of the PLC. The Minitek® Pwr 4.2 supplies power to the PLC power supply modules and servo drive controllers installed in the cabinet.
Visit our application page to know more about our connector solutions for control cabinets and other application that support Industry 4.0.