The PLC representation of NC contact is given in Figure 1.3 This contact scans for the signal
state OFF (0) at the specified bit address. Power flows through NC contact if the scanned bit address has a signal state OFF (0).
This contact is used for scanning the signal state of input devices or output devices or other internal program elements. Figure 1.4 shows PLC circuit with NC contact position using NO push button. Figure 1.5 shows PLC circuit with NC contact position using NC push button.
Figure 1.3 PLC circuit with NO contact position using NC push button
Figure 1.4 PLC circuit with NC contact position using NO push button
Figure 1.5 PLC circuit with NC contact position using NC push button