Modifying NPN output

Hi guys, I have an encoder with a open collector NPN output (i.e. sinking). Meaning it can only work with a sourcing PLC input.

If i use a pull-resistor, will i be able to get it to work with a sinking PLC input? perhaps just the CW/CCW get mixed up, thats all?

Depending on the PLC, you can sometimes wire your +DC to the COM terminal and then connect the encoder's signal wire to the input. Otherwise you can use a solid state relay, just be careful of the speed on the relay compared to the encoder.

For a regular 24V dc input to a plc, I did once use a pull-up resistor to do what you described. I have never done it with an encoder. The only problem is the logic input is the opposite what it should be. So I'm not sure what the marker pulse is going to do. Make sure to size the resistor for the correct current so you don't overdrive the encoder, and still have enough to drive the input. You should get a print of the PLC input to see what it uses, some inputs are bidirectional.

Thanks guys! I am interested to find out too. will try it out when the parts are here.