Incremental encoder

[mihan]

One, maybe silly question.

I have a PLC with 24 V supply voltage. Is it possible to connect a 12V incremental encoder as high speed input simply by bridging both 0V poles.
Thanks fot help!

[Al_The_Man]

I am not sure what you mean by 'bridge both 0v poles' but if the PLC has highspeed input you may be able to arrange a A & B input if the encoder is fed with 12v and the output is open collector , you may be able to input the collector to the PLC, it all depends on the PLC & encoder configuration.
More information is required.
Al.

[mihan]

Thanks. I meant the following. If the incremental encoder has a 12V power supply, this means that the voltage level for logical 1 from the encoder is also 12V (am I right). Is it enough for the PLC operating on 24V power supply to recognize the signal from the encoder as logical 1.

Is there a risk that any of the pulses get lost?

Thanks.

[Al_The_Man]

Thats why I mentioned it depended on if your encoder is open collector, if it is you could probabally do it easily by feeding the encoder with 12v but the open collector could be fed by a 24 SOURCE card i.e. you encoder will sink through the open collector transistor.
if it is not open collector then your PLC may see the conduction from the 24v source through to the 12 supply through the load resistor and see an input when the encoder is both high and low.
So the bottom line is it will probabally only work with the first scenario.
The other way is to put a transistor or fet (2n7000) in between to buffer the encoder.
Al.