MURRELEKTRONIK, represented in Australia by Sick , has released M12 circular connector plugs with LEDs. The indicator for normally open (NO) is amber and for normally closed (NC), white, so that the indicator can be unambiguously associated with a switch state.
Most sensor plugs have a green light and an amber light, so the user knows the sensor is connected to the power supply and that a switch state is present, but not which one. The indicators for NO and NC switches are amber in both cases, making reliable recognition at a glance impossible.
The flat format of the new plugs allows them to be installed in cramped positions. The circular plug with an LED has a combined knurled nut that permits quick manual installation using the knurled part and perfect (final) assembly or inspection with a torque wrench set to the recommended tightening torque.
An additional check is possible using the green contact bearer, which only becomes visible when properly tightened. The customer only has to make one visual inspection to see which connections are screwed in and which are merely plugged.