Why Do I Get "NAN" or "Inf" When I Run the 435x Thermocouple or RTD Example? Primary Software: Driver Software>>NI-435xPrimary Software Version: 1.0 Primary Software Fixed Version: N/A Secondary Software: N/A
Problem: I have a NI 4351 and a TBX-68T terminal block. I would like to measure thermocouples or RTDs and found examples in the LabVIEW 6.1 example database. However, when I run the example I get "NAN" or "Inf" on each of my channels. I have verified each of the channels in the test panels in MAX and they work. Solution: When run in LabVIEW 6.1, this code may not run properly. Go to the block diagram of the 435x Thermocouple Example. Find the 4350 Remove Offset VI and open it. Then go to its block diagram. Find the Convert Thermistor Reading VI. You will notice that there is a constant of "1" that is wired to the Convert Thermistor Reading VI, and is connected to the "Type of Excitation" input. A value of "1" corresponds to the enumerated value of a current excitation. Since the TBX-68T terminal block CJC used current excitation you will get erroneous data. This erroneous data is then applied to all your channels giving you NAN. In order to fix this problem, delete this "1" constant, right- click on the "type of excitation" input terminal and select Create ยป Constant, and then select Current Reference from the enumerated constant. This problem occurs in the examples for LabVIEW 6.1, but should work properly in LabVIEW 7.1 and later. Related Links: Attachments:  - 435xExample.JPG
Report Date: 11/13/2002 Last Updated: 01/31/2007 Document ID: 2RCDA22H |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
