Hardwired MCRs are used to interrupt power to the I/O rack.

Question

Quizplus · Accepted Answer

Hardwired MCRs (Master Control Relays) are indeed used to interrupt the power supply to the Input/Output (I/O) rack in industrial control systems. They are typically wired in series with the power line feeding the I/O rack and are controlled by the Programmable Logic Controller (PLC) program. When the PLC program detects a fault condition, it de-energizes the MCR, thereby interrupting power to the I/O rack and preventing further damage or hazards.

Hardwired MCRs Are Used to Interrupt Power to the I/O