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Safety in Distributed IO - EUROPE

Safety in Distributed IO - EUROPE

Safety in Distributed IO - EUROPE


I am trying to put together a main panel using Siemens an S7-300 with a ET200S. I have a Main Panel (contains the S7-300) and 2 more Aux. Panel that contain the ET200S.

I have already looked over the safety regulations for Europe and the class for the installation is the lowest. (I am using a safety relay).

This safety relay cuts the control power to the ET200S.

Is this correct? Or do i need to install several contctors in order to cut the power to thoses Aux. Panels? If so can i put the contactors on the Aux. Panel?

Thank you in advance.
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RE: Safety in Distributed IO - EUROPE

Use the fork Luke.

It has been my experience that it is best to drop the control power relay with the safety circuit. If the safety relay drops (e-stop button pressed or a guard switch actuated) a contact wired in series with the control power relay coil should do it.
Your discrete i/o nodes should be powered through a contact on your CRM or an aux. contact on the safety relay.   
Another method is to drop discrete output power through the crm connected to motion outputs supply only.

Good luck


RE: Safety in Distributed IO - EUROPE

Thank you Professor for your reply.
(gratefull i am)

At this point i have more or less what you have said. And i usually do like you have said.

My safety relay connects/disconnects the comand power from the main panel and 2 more control power relays on the auxilary panels (the power supplys were from client and i have no way of changing it).

But i still do not know whether this complies to European specifications.

I have read several papers on the subject and even the ISO rules and everything seems to point to contactors that cut the power (not the control) from all the equipment.


RE: Safety in Distributed IO - EUROPE

Pardon my ignorance Prof. but what do you mean with CRM?

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