Tech Notes
Applies To: Temperature Sensing Probes
Problem Description:
A difference in temperature between the heat source and the handle or cable end of a temperature probe can cause heat to be conducted along the length of the probe’s shaft causing a difference in the sensor’s reading versus the actual temperature.
Resolution/Work Around:
There are several factors that impact the stem conduction error, however, a suggested rule-of-thumb to overcome stem conduction errors is to immerse the probe to a minimum depth equal to 20 times the diameter of the probe plus the length of the sensing element contained in the probe.
For example, a probe that is 3/16 inch in diameter with a shaft length of 9 inches and has a sensing element that is ¾ inch long which is located approximately at the tip of the shaft would have a minimum immersion depth of: (20 x 3/16”) + ¾” = 4 ½ inches.