From NI-9123 Specifications: "The NI-9213 has an internal autozero channel, which can be subtracted from each thermocouple reading to compensate for offset errors"
Labview Help points to the FPGA Interface (for cRIO):
Use the FPGA I/O Node to access the following terminals for this device.
Terminal
Description
TCx
Thermocouple input channel x, where x is the number of the channel. The NI 9213 has TC channels 0 to 15.
Autozero
Autozero channel. For the best accuracy, read the Autozero channel in the same FPGA I/O Node as the thermocouple input channels.
CJC
Cold-junction compensation channel. For the best accuracy, read the CJC channel in the same FPGA I/O Node as the thermocouple input channels. You must convert the CJC data to temperature.
This is where I get stuck! If I go to FPGA Target and select New -> FPGA I/O, I get an Available Resource dialogue which is unpopulated. Really, I just need to know - is the NI 9213 Autozero supported in Scan Mode, or is it enabled by default (when used with a cRIO). The documentation does show Autozero in FPGA mode but not in Scan Mode.(only the thermocouple inputs are listed in Help). Any advice would be greatly appreciated.
I have been trying to understand potential sources of inaccuracy in our temperature measurements using an NI-9213 with cRIO (without FPGA). I found this calibration procedure, which I plan to try out:
It may not have anything to do with your particular situation, but it's the first document I found with step-by-step instructions beyond the basic task creation.
