Hello,
I've been working on a piece of code which measures the temperature inside and around a pressurized vessel. I'm using E-type thermocouples which provide good readings for all outside thermocouples. The vessel has a feedthrough (copper connectors), thermocouple wire on the inside and copper wire towards the DAC card. This causes bad temperature readings since the inside of the vessel is now the cold junction. I planned on using a PT100 to measure the cold junction temperature together with a NI-6218. However, I'm experiencing problems programming the variable cold junction temperature and I can't figure how to provide the new cold junction temperature to the add_ai_thrmcpl_chan block. This is my current code using nidaqmx:
# Configure thermocouple channels with cold junction compensation temperature
for channel in tc_channels:
task.ai_channels.add_ai_thrmcpl_chan(
inside_channels,
units=TemperatureUnits.DEG_C,
thermocouple_type=ThermocoupleType.E,
min_val=-196.15,
max_val=30,
cjc_source=CJCSource.SCANNABLE_CHANNEL
)
# other thermocouples
task.ai_channels.add_ai_thrmcpl_chan(
outside_channels,
units=TemperatureUnits.DEG_C,
thermocouple_type=ThermocoupleType.E,
min_val=-196.15,
max_val=30,
cjc_source=CJCSource.BUILT_IN # Using built-in
)
Any suggestions?
