Temperature readings with NI 9213 drifting up

[Notavailable]

We have been experiencing a temperature drifting problem when using NI 9213 and Signal Express 2013.

The probe readings take a long time (about a hour) to reach the correct, actual value 78.6 degC. In addition, there are losses of signal during the course of measurement.

Can somebody kindly help give an educated guess on the cause of this problem? Thank you.  

[GerdW]

Hi Alex,

is the sensor ok? Did you check for broken wires, bad cabling, bad contacts, or similar?

How do you know it's showing the correct value after an hour? (In terms of accuracy: drifting is just in the order of 10th of degreees...

[Notavailable]

Hi GerdW

Thanks for your reply.

The actual value is indicated by a mercury thermometer. Its reading remains stable at 78.6 degC, but the temperature probes (K-type thermocouples) drift slowly up to this value. Our client, who experience this drifting problem, is using Signal Express 2013, NI 9213 and Windows XP.

We ourselves use Signal Express 2013, NI 9213 (another unit) and Window 7. There is no drifting problem. We also use a standalone meter to check the temperature probe (K-type thermocouple). There is no drifting problem either.

Hence, there should exist two possibilities

1. The client’s computer runs Windows XP, and there is a communication error between the computer and the data logger

2. The client's data logger is malfunctioned

What is your opinion? Have you experienced this drifting problem? Thanks.