E-Stop to an STO?

[JeremyAdair87]

I totally agree with everything said so far, each situation is differerent. But it's worth mentioning that there are situations where you can connect an estop button directly to the STO inputs.

For example:

https://literature.rockwellautomation.com/idc/groups/literature/documents/um/20c-um001_-en-p.pdf

Example 1 - Drive Safe Torque Off Connections with Coast-to-Stop Action
and Emergency Stop Operation, Dual Channel, without External Relay

Fault Detection – A redundant (two) set of double break contacts on the Trojan
gate interlock are designed to ensure that at least one signal is sent to the Safe
Torque Off option board when the gate is opened. A single fault detected on the
safety input circuits will result in the lock-out of the system to a safe state (off ) at
the next operation and will not cause loss of the safety function.
Each of the inputs on the Safe Torque Off option board independently monitors
the status of the safety circuit and the status of the other input on the board.

Wow, its on page 11 of that manual. I would make sure OP verified that his drive had the same options. I know I have seen some dumb STO options where monitoring didn't matter. If both contacts made, even seconds apart, the drive would operate and be able to reset.

I don't like the design, but thats still pretty cool. Thanks for educating us.

 

[dwoodlock]

We just commissioned a couple machines at our plant where we implemented both SS1 and STO. First time I've ever done it that way, but it works. The E-Stop buttons activate SS1, and then we have another button on the machine that when depressed, it fires STO. Also, any general machine "fault" condition will fire STO. We use Rexroth drives.

Is this correct where you said above that a general fault opens STO and Estop triggers SS1?

I would have thought in either case you activated SS1.