Originally Posted by
Hood
I am not sure either, there doesn't really seem to be much information on the actual differences between TDC and TDB controllers. I have the TDC and it has CN13 socket for feedback and I was lead to believe that the TDB did not have it but I also remembering seeing that it was an option.
I do have a glass scale hooked up to mine on the X axis and I have my servo drives encoder output hooked up on the Z axis and thus both have feedback for out of position checking purposes
The reason I put the scale on the X was because I was not getting tools in exactly the right position after switching on, once set up they would be spot on for the rest of the time the control was on but shut down and restart then home and call a tool to go to a set position and it would be slightly out and you had to adjust the offset again. I fitted the scale to see if I could work out why and it turned out I had a parameter for homing set wrong, it was not looking for the encoders Index pulse. Once I had that set correctly then even after a restart/home the tools are exactly where the are meant to be.
Just for your or anyone else's information, when set correctly you will see the axis move to the home switch, it will back off slowly, it will then momentarily stop when it sees the switch close and then it will again start to move slowly until it sees the index pulse. If the last movement doesn't happen then the parameters for homing is not set correctly for Index homing.