Logix/PowerFlex 525/SICK Encoder

Hi all,

I've a fun one for you tonight...

I've got a ControlLogix PLC (running v17). I've got a PowerFlex 525 drive with the Encoder Card added on (for an incremental encoder).

And I've got an encoder from SICK. Yes, I know that using an AB encoder would have been easier. Long story (we didn't spec/buy/install that component).

For some reason, the drive isn't seeing encoder counts from the encoder. I have the drive configured for a Quadrature input, the wiring matches both AB and SICK's documentation for A/B channels.

One obvious question that I can't find an answer for in any of the knowledgebase or the almighty Google is whether to configure the encoder as TTL/HTL. The encoder will do either (is programmable). It also has a number of "lines" of resolution which is currently set to the default of 8,192. That seems like it will give me the appropriate resolution.

My question -- what's the special sauce here? How do I make this non-AB device talk to my AB gear and do it's job?

Appreciate any advice/directions/insights into the mystical world of non-AB encoders.

joe

Does the encoder documentation say it's an open collector output? If so, you'll likely need pull-up resistors. You can put a meter on the terminals and see if any voltage appears on them. If not, it's likely open collector and doesn't supply voltage to the AB device.