Really remote emergency stop

[Lancie1]

The control room may be 50 miles away, but the E-STOP and the means to remove power by the E-STOP will be local. Only an alarm signal goes back to the remote control room. Also the reset button for the E-STOP must be local !

Exactly right, Jesper! You summed it up nicely in only a few words. Who cares about the remote control room? It is any local operators at the machine that must have the Emergency Stop control.

 

[Kyle Sleiman]

It is not that unreliable really. Maybe you need to get one system with safety plc & safety io at bus to get the feeling for it.

I said, its no different from cut down wire on old style e-stop.

Dont be against change just becouse you have feeling about it. Take and research how those systems work.

You are now mixing things up, nowhere was said that it would be only e-stop. It was about if e-stop was needed also on remote control location.

I am aware of Safety PLCs, and I have done hundreds of systems with wireless communications involved...I do know they are (seem) reliable at times (when there is no noise near the system), but again , if an Emergency switch goes wrong, it only cost 10 bucks to replace it and any electrician can diagnose / replace the faulty switch...

can we say the same about your Safety PLC ? or wireless emergency switch which is 50 miles away ?

any one here with more than 15 years in the trade KNOWS how it is in a plant when the customer is looking at you, hoping you get it fixed in an hour max... not go and check for the safety PLC software and get familiar and then study the code...or find replacement for your wireless E switch!


get my point ?

other than that...I don't mind change of new technologies if it is for better NOT worse.

Kyle

 

[TurpoUrpo]

I am aware of Safety PLCs, and I have done hundreds of systems with wireless communications involved...I do know they are (seem) reliable at times (when there is no noise near the system), but again , if an Emergency switch goes wrong, it only cost 10 bucks to replace it and any electrician can diagnose / replace the faulty switch...

can we say the same about your Safety PLC ? or wireless emergency switch which is 50 miles away ?

any one here with more than 15 years in the trade KNOWS how it is in a plant when the customer is looking at you, hoping you get it fixed in an hour max... not go and check for the safety PLC software and get familiar and then study the code...or find replacement for your wireless E switch!


get my point ?

other than that...I don't mind change of new technologies if it is for better NOT worse.

Kyle

Context was not only wireless, but also wired ethernet.

One can use normal e-stop switches with safety plc. In well done system there is diagnostics that gives you instantly broken switch. You dont need to find it, its just needed to replace. It saves lot of time in bigger systems. Anyone in here knows, that finding where the fault lies is most time consuming many times.

Get my point? Well done system with safety plc is lot faster to get up and running than same thing done with hardwired & relays. I know, I have been searching for malfunctioning switches for many times, when it is broken so that it malfunctions only sometimes, it is very hard to find. But with safety plc, system would tell which one it was and it could be just replaced!

You basic electrician knows how to change simple e-stop?

ASi safety is other thing, dont mix it in this.

 

[The Plc Kid]

I have setup safety plc systems in ASI,Devicenet and Ethernet/IP.

ASI works but is a PITA to troubleshoot. Devicenet works well also but does have it's own following.

We are upgrading systems as we go to be Guardlogix PLC's with PowerFlex 755 drives with safe speed and safe off options as well as using the safety Point I/O in our equipment.

All my equipment is very large meaning several hundred feet long and 2-3 stories high each with serveral hundred I/o just for safety. If we had to do this in hard wire it would be very expensive and hard to find faults wiring the I/O in zones.

This way all safety device have their own input or output point. You can do wireless point I/O to a control room if you need a estop there and use the I/O on the same block for other funtions.