K-Type Thermocouple Spice Model

[veryevil]

Hi, I'm looking for a spice model (LTspice preferably)  for a K-type thermocouple.

Anyone have one or clever enough to make one from NIST tables?

Cheers

[T3sl4co1l]

How would you want that, with a TEMP input pin?  Otherwise you have to specify device temp which is really only usable with parameter sweeps I think...

Have you looked around for one?  Wouldn't surprise me if it's out there for free, it's easy enough.

I could write one but it'd be a few hours work writing and testing... maybe someone else here has the spare time to?

Tim

[veryevil]

Hi, the only one I could find was a J type. I managed to modify it with the correct polynomial for a k-type and it's working.

I was going to post it on here but forum was out most of yesterday.

When I get back to my computer I'll post it.

Thanks

[veryevil]

Code: [Select]

* K-Type thermocouple subcircuit for LTSpice
* Using reference function on ITS-90 (International Temperature Scale of 1990)
* Temperature range: -270.000 to 0.000 degC
*                       0.000 to 1372.000 degC
*
*            Tjunc = Input voltage representing the thermocouple junction temperature
*            | Tref = Input voltage representing the cold-junction temperature
*            | | Vtc+ =
*            | | | Vtc- =
*            | | | |
.SUBCKT TC_K 1 2 3 4
*
E_TJ 5 0 VALUE = { IF(V(1) <= 0,
+   0.000000000000E+00          +
+   0.394501280250E-01*V(1)     +
+   0.236223735980E-04*V(1)**2  +
+  -0.328589067840E-06*V(1)**3  +
+  -0.499048287770E-08*V(1)**4  +
+  -0.675090591730E-10*V(1)**5  +
+  -0.574103274280E-12*V(1)**6  +
+  -0.310888728940E-14*V(1)**7  +
+  -0.104516093650E-16*V(1)**8  +
+  -0.198892668780E-19*V(1)**9  +
+  -0.163226974860E-22*V(1)**10 ,
+  -0.176004136860E-01          +
+   0.389212049750E-01*V(1)     +
+   0.185587700320E-04*V(1)**2  +
+  -0.994575928740E-07*V(1)**3  +
+   0.318409457190E-09*V(1)**4  +
+  -0.560728448890E-12*V(1)**5  +
+   0.560750590590E-15*V(1)**6  +
+  -0.320207200030E-18*V(1)**7  +
+   0.971511471520E-22*V(1)**8  +
+  -0.121047212750E-25*V(1)**9  +
+   0.118597600000E+00*EXP(-0.118343200000E-03*(V(1)-0.126968600000E+03)**2) ) }
*
E_TR 6 0 VALUE = { IF(V(2) <= 0,
+   0.000000000000E+00          +
+   0.394501280250E-01*V(2)     +
+   0.236223735980E-04*V(2)**2  +
+  -0.328589067840E-06*V(2)**3  +
+  -0.499048287770E-08*V(2)**4  +
+  -0.675090591730E-10*V(2)**5  +
+  -0.574103274280E-12*V(2)**6  +
+  -0.310888728940E-14*V(2)**7  +
+  -0.104516093650E-16*V(2)**8  +
+  -0.198892668780E-19*V(2)**9  +
+  -0.163226974860E-22*V(2)**10 ,
+  -0.176004136860E-01          +
+   0.389212049750E-01*V(2)     +
+   0.185587700320E-04*V(2)**2  +
+  -0.994575928740E-07*V(2)**3  +
+   0.318409457190E-09*V(2)**4  +
+  -0.560728448890E-12*V(2)**5  +
+   0.560750590590E-15*V(2)**6  +
+  -0.320207200030E-18*V(2)**7  +
+   0.971511471520E-22*V(2)**8  +
+  -0.121047212750E-25*V(2)**9  +
+   0.118597600000E+00*EXP(-0.118343200000E-03*(V(2)-0.126968600000E+03)**2) ) }
*
E_TC 3 4 VALUE = { (V(5)-V(6))/1000 }
*
.ENDS