Hello,
I have a UR5 CB3 robot from 2014, and I’m wondering if it is possible for this robot to use conveyor tracking. It is currently running URSoftware version 3.15.8.
Not to be smart or anything, but have you read up on it yourself just a little bit before asking? 
Here’s an article about how to set it up in the CB3: Conveyor tracking guide - 18208
yes I did but, For some reason, most of the information I found was for the e-Series, and the few references to the CB-Series mentioned that an extra module might be needed.
It kinda looks like i need some kind of controlbox when im using an absolute encoder?
You’re right that most documentation today is on the e-series. It can drown out the older material. 
I have not tried with absolute encoders, so I cannot help you with that I’m afraid. But it does say in the guide, that you might have to use a MODBUS signal, yeah.
Yeah im currently trying to look a bit more into that part of it, and thanks for the help