CLiu,
The FP-TC-120 has a CJC channel and the positions field would be set to hex 0100 to set the range and/or attributes. The FP-RTD-122 is an RTD measurement module and does not have a CJC channel, so there is no valid value for the positions field to access CJC.
Regards,
Aaron
LabVIEW Champion, CLA, CPI