Common Emergency Stop 1

[118811]

I need an advise from forum members on the following:
I have 10 direct online drives utilizing smart motor protection relays and 3 ABB VSD drives that have an existing field local control station (start, stop, e-stop). I need to upgrade this system and provide a centralized common e-stop (kill all emergency stop). When activated this e-stop shall stop all of the 13 drives.
I like to find out how to implement this “kill all” e-stop so that it is legal and is inline with any standard you might know of.
Do I purchase an e-stop with multiple contacts and hard wire the contacts back to each individual drive circuit? Don’t know if I can find an e-stop with 13 contacts?
Do I puchase a simple e-stop and wire back to the PLC and let the PLC send a stop signal to each drive? Don’t know if that’s legal or is inline with any standards.
Any advice on how best to do this is kindly welcomed.

 

[waross]

How about a pair of 8 pole relays as master control relays? One simple normally closed E-stop button to interrupt current to both relays.

Bill
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"Why not the best?"
Jimmy Carter

 

[ScottyUK]

Over here in the UK the 'Pilz' brand of safety relays are an industry standard. They provide a number of positively-guided safety contacts, and expansion modules are available for applications requiring multiple contacts. There are other manufacturers too - Rockwell, for example.


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If we learn from our mistakes I'm getting a great education!

 

[FreddyNurk]

Waross and Scotty have the bases covered. Master control relay if you want to stick with hard wired E-Stops and relays, or a Safety relay if you want to go the more fancy option.

Control relays are probably cheaper, if you want to go that way. If your application needs some sort of reporting of what E-Stop has been activated and where, then the Safety relay is probably the better option.

I wouldn't be using a normal PLC for any E-Stop functions.

 

[rhatcher]

Waross has a good (lps) answer. Use a single n/c switch to control the power to the coils of two (or more, as required) n/o relays. Then connect the n/o relay contacts in series with the individual drive e-stop circuits. The use of the n/c switch and the n/o relay(s) provides, in my opinion, fail-safe protection.

I would add that if one more more of these drives are installed on a single machine that there may already be a single e-stop circuit that controls multiple drives. If this is the case, you may not need 13 output contacts from your master e-stop switch/relay combination.

However...My opinion does not necessarily meet the requirements for the electrical code in your region, the requirements for the type of industry you are in, or any specific requirements that your employer (or client) has.

You should be familiar with all of the above requirements when judging what design is best.

 

[118811]

Thank you all kindly for your helpfull feedback.