Greetings,
I'm currently working with a CR10X in a data acquisition project. I'm having problems with thermocouple measurements, because I don't have an adequate cold junction compensation measurement. Looking in the operator's manual it is stated that the CR10X's internal temperature is not suitable for CJC, and it is recommended to use a CR10TCR temperature probe. The thing is that I can't find the probe (maybe it was never bought), so I tried to use a MCP9700A (temperature sensor) as CJC, but it didn't work, because the thermocouple data equaled the CJC data (the same happened when using CR10X's internal temperature).
My question is:
the only way of providing CJC for thermocouple measurements is using a proprietary sensor, like the CR10TCR or the 107 temperature probe?
This is part of the program I'm using:
1: Volt (SE) (P1)
1: 1 Reps
2: 25 2500 mV 60 Hz Rejection Range
3: 1 SE Channel
4: 1 Loc [ MCP9700A ]
5: 0.1 Multiplier
6: -50 Offset
2: Thermocouple Temp (DIFF) (P14)
1: 1 Reps
2: 21 2.5 mV 60 Hz Rejection Range
3: 2 DIFF Channel
4: 4 Type J (Iron-Constantan)
5: 1 Ref Temp (Deg. C) Loc [ MCP9700A ]
6: 2 Loc [ Temp1 ]
7: 1.0 Multiplier
8: 0.0 Offset
Thanks in advance.
All CR10X dataloggers were shipped with a CR10XTCR (thermistor and wiring panel cover). The thermistors are small, so easy to lose.
You can purchase the thermistor and the cover, or just a replacement thermistor. The part number information can be found here:
https://www.campbellsci.com/cr10xtcr-overview
There's also a picture, so if it is lost, it may be easier to find if you know what to look for! :)
Dana W.
To answer the original question though you can use any temperature sensor the logger can read as the reference. As you seem to work out as long as the scaled temperature in deg C is in the Ref Temp location for the thermocouple instruction it will use that temperature as the reference.
As far as I can tell your program is correct providing the thermocouple is wired into differential channel two.
I would expect that you should see a change in Temp1 if the thermcouple is heated/cooled. If not then check the probe is made and connected correctly.
I'll keep working on it, and I'll let you know how it goes.
Thanks.