allen bradley connections to encoders

[natahn]

Im working on a project and we are trying to control an old robot arm with an allen bradley plc and a dc servo motor with a 2 channel encoder.We are unsure of how to do the ttl logic to power it and then hook it up to the plc.Any feedback would be great or a reference schematic of something similar to look at would help alot.thanks

[membruce]

Since you say it is an old robot and a servo system, I am going to dues that it's a Puba brand. If that is correct, then there are some voltage comparators in the controller. You can position the arm by varying the voltage fed from the processor side at a contact point in that circuit.

BE CARFUL!!!!!!!!!! One of the disadvantages of servos on robots is that they can malfunction and suddenly swing at full power and speed. Someone in the way could be cut in two. I had one do this one time and it turned the pallet it was bolted on into scrap wood.

If you haven't done this kind of thing before, I would think twice about trying it.

Good luck,
Bruce