Does anyone use Type C thermocouples?


Thread Starter

Ken Roach

Hello, List:

One of my application engineers has a customer application with a Type C
thermocouple, for which our thermocouple input modules don't have a
linearization algorithm. An hour's worth of searching the web indicated that
the big makers of thermocouple signal conditioners (yes, Action I/O was the
first place I looked, Jim) don't use them, either.

Does anyone know of a signal conditioner with a type C thermocouple input and a
0-10V or 4-20 mA output?


Ken Roach
A-B Seattle
[email protected]

Gabriel Gomez

Dear Ken,
Honeywell has a smart temperature transmitter model STT 3000 that includes the type C termocouple input(0 ~ 2300 =B0C or 32 ~ 4170 =B0F).

Other company that you can contact is M-System Co. Ltd. from Japan (K-unit signal conditioner).


Gabriel Gomez
DIOXITEK S.A. Nuclear Fuel Plant
[email protected]

Moore Industries Model TRY & TRX PC-Programmable Temperature Transmitters
cover 9 different thermocouple types including "C". Mescon offers a "smart"
transmitter (SST-200) that does the same thing.

Robert Scott


Try a company called Caledonia Instrumentation Ltd. Tel. No. 0044 141 952 8787
ask for Roy Stump(sales engineer)

Unit : Status SEM 220
Inputs : Current(0 - 10.0 Amps), Volts(0 - 1000.0 Volts),
RTD(Various Types), Thermocouple(All Types)

I hope this is what you are looking for

Bert Scott
Instrument Project Engineer
Central Engineering Department
Roche Products Limited
Ayrshire KA24 5JJ
Phone: +44 (0)1294 836584
Fax: +44 (0)1294 836302
I believe that's a tungsten/rhenium.... high temp.... Omega (look up the web
site) has a temp controller that will read type "C" (section "P" of the Temp. catalog)...

Marc Landry
Master Research Technician
National Renewable Energy Labs
Golden, CO
[email protected]

Eric M. Klintworth


My curiousity got the best of me, so for everyone else wondering what a
Type C thermocouple is...

A Type C thermocouple is tungsten 5% rhenium (+ lead) and tungsten 26%
rhenium (- lead). Type C is also known as W5, according to one source
(Type C is the same as W except the W + lead has no rhenium). The Type
C temperature range is 0 to 2315 deg C (32 to 4199 deg F). The Type C
curve is more of a straight line verses Type W, and the Type C is said
to be a bit less brittle than Type W.

As for signal conditioners, the Moore Instruments TRY and TRX series
( and Phoenix Contact MCR-T-UI transmitters both support
Type C thermocouples.

Eric M. Klintworth, P.E.
Columbus, Ohio

Shawn Parrish

Action Instruments does have a unit that will do type C thermocouple, the
Q486 and the Q488.
Linearising type'C' (formerly W5)
This type was adopted in March 1974.
Hoskins Manufacturing Co.
mV/deg C listed in NBS mongraph 125 p.402
Reprinted with permission of Hoskins.

A third order polynomial fits adequately between
500; 2300 deg.C
In the lower range (0; 500)
that global polynomial fits the best v/s
other order polynomial.

Your equation:
x= mV (millivolts)

a0 = -9.744966
a1 = 65.600825
a2 = -1.0236416
a3 = 0.02537307
For more info:[email protected]

Note: coefficients extracted using

Remember this is the best polynomial as a global one.I'm not saying it's the the best for your application range. This type has an uncertainty
of 5 deg.C + the extension line + the gradient
+ the installation + the input ...
all in a statistical approach will provide
around 10 deg.C uncertainty.