MESA LABORATORIES, INC. DataTrace Division
Standard
Operating
Procedure
Release Date: August 27, 2010
Page: 23 of 32
Revision B
I. Program the Tracers to be tested for 30 second intervals, starting approximately 15
minutes before they will be placed in the oven or dry well calibrator.
J. Insert the programmed Tracers into the isothermal block in the oven or into the holes
in the dry well calibrator.
K. Insert the reference probe into the isothermal block in the oven or into the
appropriate hole in the dry well calibrator.
L. Set the oven temperature for 125°C nominal.
M. Wait for the temperature indicated on the reference’s display to stabilize. When it
stabilizes, write down the temperature indicated and wait 10 minutes. If it has not
changed by more than 0.1°C in 5 minutes it is stable enough for a reading.
N. Write down the time and temperature, then set the oven for 205°C nominal and
repeat step 5.
O. Write down the time and temperature, then set the oven for 275°C nominal and
repeat step 5.
P. Write down the time and temperature, and then turn the oven or dry well calibrator
off.
CAUTION: BE SURE TO WEAR WELDERS GLOVES WITH GAUNTLETS WHEN
HANDLING HOT OBJECTS FROM THE OVEN!
Q. After the Tracers have cooled enough to handle comfortably, remove them from the
oven.
R. Read the data out of the Tracers with the DT program.
S. Compare the temperature the Tracers measured with the recorded temperature the
reference indicated.
CAUTION: MAKE SURE YOUR PROCEDURE DOES NOT EXCEED THE
THERMAL PACKS TIME AND TEMPERATURE LIMITS!
8.7.2. Humidity Tracer
This procedure describes a method for verifying the humidity measurement accuracy of Humidity
Tracers. The temperature calibration should be verified with the procedure in section 8.7.1. before
the humidity calibration is verified. If a bath is used for temperature verification, a protective cap
(124756-002) must replace the normal dust cover on the Humidity Tracer before it is submerged
in the bath. This humidity procedure can be performed on a Tracer any time accuracy needs to
be verified.
A. Tracers are normally tested at several humidity values. We recommend that humidity
values are selected which are critical in reference to the target process.
B. The test can be performed by using either a humidity generator or a fixture with
certified salt solutions.