[bmcd]

Thanks Claude for the link. I read through it and I must admit it devises a formula for the value of the power dump resistor, though it's a bit complicated. Electronics is not my strong point, but this project has forced me to start looking at it a bit more. I will study the article and see if I can get the specifications needed and do some of the calculations.

From what I think I infer from this link is the basic design of what I've posted seems to be correct (I hope). Possibly the only thing to consider is the value of the dump resistor, which I just used Gecko's formula for my posted circuit.

Bob

[Claude Boudreau]

The full current, although low, because its the primary of the step down transformer is flowing thru the estop ...I think this circuit is much better, depending on your setup many estop buttons can be installed in serie with just the relay coil current going thru them (less expensive components)

http://www.geckodrive.com/electromechanical-estop

[Claude Boudreau]

the following is from gecko 320 application notes and gives more info on the resistance value...
http://www.geckodrive.com/returned-energy-dump