How to connect + Program wire encoder

[captainpatje]

Hi all,

I am not a PLC expert but can find my way within the program and would like to develop much more.
For work (We sell industrial bandsaws) we have purchased a Posital Fraba wire encoder, and we would like to hook it up to our Mitsubishi FX3G PLCs to measure at what height the saw bow of the bandsaw is at that moment.

Unfortunately I have little experience with connecting these things, as other encoders used in our machines are pre-installed by our factory.

Below is described what functions the wires have.

What I thought was the following: Pin 1 goes to an input of the PLC
Pin 2 goes to + (or 24V)
Pin 3 doesn't go to "Ground" as they describe, but instead to - (or 0V), which is technically ground

Pin 4 and 5 we don't use, correct me if I am wrong. The saw bow goes up and down only, and I thought we don't need to use these wires.

 

I connected it like this, connected wire 1 to X0 on PLC and just to test I made the program read:

 

M8000 ------------------------------ C235 k99999

 

But the value stays 0, whether I pull the wire or not. So something is wrong, but what, I really can't figure out.

Hope someone can help!

 

[Gambit]

Did you check if it is a 24V encoder ?

 

[glavanov]

Pay attention to encoder's operation/installation manual.

Look's like this is analogue current or voltage output encoder, so pin 1 (green wire) is 0-5/10V or 4-20/0-20mA. You need to add analogue input adapter (analog to digital) ot your Fx3G.

With pin 4 and 5 you should teach zero value position and the rotation direction you want the encoder to output positive analogue value.

 

Edited August 21, 2020 by glavanov

[Ron_S]

glavanov is right - you bought the wrong encoder