Incremental Encoder Configuration

[afm]

Hi all,

I am using a B&R X20 unit and want to integrate an incremental encoder (OUT A, B, & Z). I have three BOOL digital input pins for my A,B, and Z signal, but I don't have a high speed counter type function block to use for my counts. For reference I am using a X20MM4455 Motor module that is configurable for encoder counts. What are some other ways to approach this? Thanks!

 

[afm]

Hi,

The A and B signal and total counts counter is working properly, however the Z reference signal is still not visible. The signal is wired and configured properly and the module light blinks when the Z is high, however I cannot see the signal be true when i monitor it live (I can see A and B switch between T/F). B&R mentions that its unlikely to catch it being true in monitor mode. I tried using a counter to check for pulses, but again it never switches the Z signal to true. I am new to encoders, are Z signals handled differently than other signals? How can I read the signal state?

 

[robertmee]

How fast is the encoder revolving? The Z pulse is a shorter pulse and occurs once per revolution. The pulse duration may be shorter than the ability of your input card to see the transition. If it's not that, then you may be looking at the wrong address in the PLC vs the module indicator you say you're seeing.

 

[OkiePC]

Robert is right about the Z pulse being very short in duration.
I don't know B&R gear, but after Googling that I/O module it appears to be built with four encoder inputs "configurable for AB and ABR incremental encoders", so I suspect that the module either needs further configuration and perhaps any associated function of the Z-pulse will need to be monitored differently than a typical discrete input.