It’s not always possible or practical to remove
instruments from a process for calibration. In situ
verification at a single point may be the only way
to know whether an instrument is performing
as expected. A single point verification is
most effective over a narrow temperature
range and when combined with other trends
and information related to the process and
equipment. It also requires the process not to be
in a dynamic state of change.
In a single point process temperature verification,
a temperature standard such a reference PRT
connected to a readout such as a 1523A is
placed in thermal equilibrium with the sensor of
the instrument to be verified without removing
it from the process. Usually this is accomplished
with a test well that is installed in a location
adjacent to the sensor to be tested.
The reading from the temperature standard is
compared to the reading on the panel meter,
controller, or transmitter to determine the error
and prove the tolerance condition of the loop.
Suggested test tools
Using a precision thermometer for single
point process temperature verification
1551A Ex “Stik”
Thermometer
Readout
See pg 20
1524-P1
Reference
Thermometer
See pg 20
1523-P1
Reference
Thermometer
See pg 20
1552A Ex “Stik”
Thermometer
Readout
See pg 20
52
Temperature Applications