Sick Proximity Sensor 5-Wire M12 PNP Wiring to PLC Input—No Signal Detected

Hi,

 

I have been presented with 2 x Sick proximity sensors at a clients site to detect product entering/exiting a machine to varify line running etc. I was expecting this to be a 24vdc input to my panel which I have PLC input provision for. Unfortunatley I cannot quote a part number for the sensor.

 

I am trying to work with the sensors but am not having any success yet. I assume the sensors are PNP as they have been purchased in UK and that appears to be the norm. When I supply the device with 24vdc the green lamp illuminates and when I place a body for it to detect infront there is a yellow lamp that illuminates on and off when blocked. The sensor has a pre made 5 wire M12 connector (like a Brad Harrison cable) connected to a terminal box to extend the cable back to my panel. I can measure the 24vdc supply and measure 24vdc on the "switch" when the sensor is dectectin a body. As soon as I connect that "switch" to the terminal in my panel for the input the previously measured 24vdc drops to 5.7vdc so this is insufficient to drive my input. There is a 2nd sensor that wires straight back to the panel with out the terminal box and that behaves in the same manner.

 

Is the wiring incorrect or do I have the wrong type of sensor for the application?

 

Any help that can be offered will be appriciated.

 

Thanks!

Hi Mark,

I think you need a driver for that 24Vdc.
Try passing the 24V through a buffer amplifier [power amp].

Hope this helps.

Warm Regards,
Justin

You really can't make any assumptions about the output configuration, you need to get the part number. Some Sick proximity detectors have a linear output, just to add to the mix,
cheers,
Richard