Information

8
Suggested test tools
HART Smart Temperature
Transmitter Calibration
Smart temperature transmitters, with their flexibility and enhanced
accuracies, have become the number one temperature calibration
workload for instrumentation professionals.
Calibrating a HART smart temperature transmitter requires an
accurate temperature simulator or temperature source,
mA measurement, and a HART communication tool for calibration.
You can use separate tools or a calibrator that integrates all three
to perform this task.
Before going to the field: Gather the needed calibration
and communication test tools. If testing a RTD transmitter, be
sure to bring extra test leads for connections. Testing a 3-wire
RTD requires five (5) test leads, three for simulating the RTD
sensor and two for measuring the mA signal. If using a separate
communicator, you will need its test lead set as well.
For thermocouple (TC) calibrations, be sure to have the correct TC
test wire type with a mini-connector terminated with the correct TC
connector type, (i.e. Type K wires and connector to simulate a Type K
thermocouple).
To get the accuracy needed: As a rule of thumb, your mA
measurement tool and temperature source calibrator should be at
least four times more accurate than the device being tested. To
make that determination, the data sheets of both the transmitter
and the calibrator being tested need to be considered. Be sure
to account for temperature and stability (time) in addition to
the accuracy the devices have specified. For more information
on determining accuracy and interpreting accuracy, see the
“Interpreting Specifications” application note referenced at the
end of this article.
7526A Precision
Process Calibrator
See pg 31
726 Precision
Multifunction
Process
Calibrator
See pg 30
714B
Thermocouple
Temperature
Calibrator
See pg 30
754
Documenting
Process
Calibrator
See pg 29
712B RTD
Temperature
Calibrator
See pg 30