We have just finished an installation that uses two AM25Ts to read 50 type T thermocouples. We have created and tested a program and verified that all sensors are being measured properly.
We are now at the point where we would like to incorporate correction factors to calibrate the thermocouples. Each thermocouple was calibrated in an ice bath by one of the parties involved with the project. Here is a sample of the calibration information they gave us (note that the sensors were only calibrated at 0 deg C):
Sensor 1, Location 1: Temperature read in ice water bath in degrees celsius = +0.3
Sensor 2, Location 1: Temperature read in ice water bath in degrees celsius = +0.5
I'm wondering how we incorporate this correction factor into our program. After reading a few other threads on this forum I understand that if we use a thermocouple instruction (as in the example below) in our program with the correct thermocouple type the typical non-linearity of the thermocouple will be corrected for.
AM25T(Temp_C(),25,mV2_5C,1,1,TypeT,RTempC,1,2,1,True,0,_60Hz,1,0)
However, this doesn't address the offset temperature measured in the ice bath. Can I account for this by adding the offset directly to the data table definition?:
DataTable(AM25T_Loc1to5,True,-1)
DataInterval(0,15,Min,10)
CardOut(0,-1)
Sample(1,RTempC,FP2) 'On-board reference temperature
Sample(1,Temp_C(1)+0.3,FP2) 'S1-1
Sample(1,Temp_C(2)+0.5,FP2) 'S1-2
Any help would be greatly appreciated.
* Last updated by: ZEI2 on 8/9/2011 @ 9:09 PM *
The best place to use your offset would be in the offset parameter of the AM25T instruction.
Store the offsets in an array.
Look at section 9.9.5 in the CR1000 manual.