What is the influence of differences in roll temperature on the measurement?
No significant effect. It is important to remember that the instrument is measuring variation in roll diameter. If the probe is zeroed at one end of the roll then it can be traversed across the roll in say 10 seconds or less. If the roll surface is at 100 degrees Celsius then the error is the amount the yoke would expand as a result of radiated heat from the roll surface in 10 seconds.
