Which statement best describes a common reference in PLC sensor wiring?

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Multiple Choice

Which statement best describes a common reference in PLC sensor wiring?

In PLC sensor wiring, the common reference is the shared ground path that all sensors and the PLC inputs refer to. This ground provides the return current for sensor signals and a stable zero-volt reference so the PLC can interpret the input voltages correctly. Without a common ground, signals can float or drift, causing incorrect readings and noise or differences between devices. The data bus is about communication, not the signal reference. The shield protects against EMI, but it isn’t the main signal reference path. The supply voltage powers devices, but it isn’t the reference the inputs use to measure signals.

In PLC sensor wiring, the common reference is the shared ground path that all sensors and the PLC inputs refer to. This ground provides the return current for sensor signals and a stable zero-volt reference so the PLC can interpret the input voltages correctly. Without a common ground, signals can float or drift, causing incorrect readings and noise or differences between devices. The data bus is about communication, not the signal reference. The shield protects against EMI, but it isn’t the main signal reference path. The supply voltage powers devices, but it isn’t the reference the inputs use to measure signals.

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