Surge protection on thermocouple inputs
Surge protection on thermocouple inputs
(OP)
Didn't find anything definitive in a search here, and I Googled the web, too.
One of my minor stations took a pretty good lightning hit during a recent storm and blew a bunch of I/O cards, all RTD and thermocouple inputs.
Not really in my purview as a power guy, but is there a particular surge suppressor made to be inserted between the thermocouple wire going to the field and the I/O card for our control system.
I found several different surge suppressors for RTD's but I seem to be missing something that will work for the thermocouple circuits. If you have specific models in mind, I'd prefer DIN rail mounting.
One of my minor stations took a pretty good lightning hit during a recent storm and blew a bunch of I/O cards, all RTD and thermocouple inputs.
Not really in my purview as a power guy, but is there a particular surge suppressor made to be inserted between the thermocouple wire going to the field and the I/O card for our control system.
I found several different surge suppressors for RTD's but I seem to be missing something that will work for the thermocouple circuits. If you have specific models in mind, I'd prefer DIN rail mounting.
old field guy





RE: Surge protection on thermocouple inputs
Easy to change I/O cards.
You may be able to ground one lead of the thermo couples.
A close hit by lightning is hard to protect against.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Surge protection on thermocouple inputs
You've mirrored my thoughts so far. Management (and the instrumentation guys) doesn't want to go with remote transmitters because of the complexity of the changeover.
I just had a conversation with the boss bout protection against really close/vigorous hits. I was hoping somebody knew of a DIN-mount device I could put in the control cabinet between the incoming TC lines and the I/O card. Such things are common as mud for other I/O
old field guy
RE: Surge protection on thermocouple inputs
I've had good luck with Ditek, they're mostly into commercial-grade stuff. See what you can see at www.ditekcorp.com, or get in touch with their tech support guys.
With just a thermocouple (low impedance, small signal), you might be able to get some relief with just a bunch or 15V MOVs across the TC terminals and to ground?
Just my thoughts...
Let us know what you decide on!
Good on ya,
Goober Dave
RE: Surge protection on thermocouple inputs
Put whatever suppressors you can find on the system. The next time you get a close in hit, say:
"Wow. It's impossible to protect against a hit that close!"
And then replace the I/Os and the surge suppressors. grin
Seriously, Goober Dave may have the best answer.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Surge protection on thermocouple inputs
Of course, an I/S barrier costs almost as much as a low end temp transmitter.
RE: Surge protection on thermocouple inputs
Keith Cress
kcress - http://www.flaminsystems.com