RTD lead extensions, can I use terminal blocks?
RTD lead extensions, can I use terminal blocks?
(OP)
Hi, all:
I've read a few posts and think I might have the answer, but thought I would run this for any experts who can confirm. I have an RTD whose leads are not long enough to reach my controller input (an Opto 22 RTD "puck"). My initial thought was to terminate the leads at a signal conditioner to turn the signal into a 4-20 mA to run into an analog input, but then I started to wonder if I can just run the leads to terminal blocks and then just continue onto the RTD input with stranded cable.
Can I do this? If so, I'm guessing I need to use "extension grade" thermocouple wire with the same ANSI type materials as used in the RTD leads.
Thanks to anyone who can provide more information.
I've read a few posts and think I might have the answer, but thought I would run this for any experts who can confirm. I have an RTD whose leads are not long enough to reach my controller input (an Opto 22 RTD "puck"). My initial thought was to terminate the leads at a signal conditioner to turn the signal into a 4-20 mA to run into an analog input, but then I started to wonder if I can just run the leads to terminal blocks and then just continue onto the RTD input with stranded cable.
Can I do this? If so, I'm guessing I need to use "extension grade" thermocouple wire with the same ANSI type materials as used in the RTD leads.
Thanks to anyone who can provide more information.





RE: RTD lead extensions, can I use terminal blocks?
That's not really true. A typical TC circuit consists of the TC junction of the dissimilar metals going to a secondary junction. From the secondary junction copper wire can be used. However, that junction now is your reference junction. As long as the reference junction is at the same temperature as the measurement junction, no extraneous emf is induced. If the reference junction temp varries, it must be compensated for, usually electrically.
RE: RTD lead extensions, can I use terminal blocks?
An alternative is to use a Temperature transmitter, which then outputs a 4-20mA signal. At my facility we use transmitters for critical applications, because you can get 4 wire redundant RTD transmitters, for everything else we use platinum 100 ohm RTD's, because they are much, much cheaper.
Ken
RE: RTD lead extensions, can I use terminal blocks?
RE: RTD lead extensions, can I use terminal blocks?
Thanks in Advance
RE: RTD lead extensions, can I use terminal blocks?
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RE: RTD lead extensions, can I use terminal blocks?