Atex Zone 1 PLC

[kimao]

Hello
Do any of you know of a PLC with an Atex Zone 1 approval? Does this exist? We have an application on a piece of mobile equipment where we need the PLC to be in the zone. Enclosing the PLC in an ExD cabinet is not an option.

Thank you

 

[Bullzi]

From what I have seen on the web the best you are going to find is Zone 2 stuff. I would say you have 2 choices: 1) Move the PLC out of the area or 2) Put it into a Purged Box.

 

[nonuke]

I agree with Bullzi 100%.
Siemens and Stahl have HMI's for zone 2 but not PLC's.

 

[Chris Hasler]

Siemens can do conformally coated PLCs, which I think have the lowest possible zone 2 rating. Maybe, with lots of limitations and a big price tag attached.

Your best bet is to build the PLC and hardware in a purged cabinet. A bomb (explosion) proof cabinet might be an option, but would be a right pain to build.

If the customer does not want purged or bomb proof cabinets then your only option is to fill the enclosure with epoxy and turn it into a giant brick.
You wouldn't be able to use circuit breakers, because you have just glued it on, and all relays would need to be sealed or they wont work (glued on or off).
If one of the fuses pops your screwed because its near impossible to dig it out of the epoxy. Your pressure transducer wiring can't be replaced for the same reason.

Purged cabinets are the future for you

 

[kimao]

What you refer to as a bomb proof cabinet is an ExD enclosure. This might be a problem due to it's size. I see some vendors have HMI's or IPC for Zone 1. Putting a soft PLC in one of these might be the solution. I/O in Zone 1 is not a problem.