How do I choose between a Normally Open (NO) and Normally Closed (NC) sensor ouput?
Normally Open sensors do not pass power to the PLC until an object is detected. Normally Closed sensors always pass power to the PLC until an object is detected. The majority of AutomationDirect sensors have Normally Open outputs, however, the PKW, PMW and CT1 series sensors are available with Normally Closed outputs.
