Different values on a resistance meter when exchanging the red and black probes

A

This may be attributed to thermo-electromotive force.
There is more effect if a resistance meter applies a DC current and reads the electric potential difference, like that on the 3540.
The following countermeasures should be considered if the measurement value has a larger error due to thernal electromotive force.

1) Use the average by exchanging the probe terminals
2) Stabilize the ambient temperature to avoid changing of thermo electromotive force due to temperature.