12
12.2
95-8616
CALIBRATION
GT3000 CALIBRATION
The GT3000 supports one person calibration, which
can be initiated locally using a calibration magnet, or
remotely with a command from the HART interface.
The calibration process is automatic, with the exception
of gas delivery. LEDs on the transmitter guide the
operator when to apply and remove the calibration gas
See Table 5.
NOTE
The HART interface allows the operator to adjust
the calibration gas concentration within the range
of 30 to 90% full scale. The default value for all
gas sensors except oxygen is 50% full scale.
Oxygen sensors use a default value of 20.9%.
All GT3000 gas detectors require a two-point
calibration — zero and span. The calibration process
can be initiated using the magnetic switch or through a
HART interface, such as the UD10/UD20. All sensors,
including oxygen, should be in clean air (20.9% oxygen)
when the calibration sequence is initiated.
The calibration process proceeds automatically after
initiation. Onboard LEDs signal the operator when to
apply the calibration gas and inform of the progress.
The calibration can be aborted by activating the
magnetic switch or with a command from the HART
communication device in lieu of applying the calibration
gas.
If the calibration process takes longer than 10 minutes,
the detector will time-out and signal a calibration fault.
If the calibration sequence is aborted or not completed
successfully, the detector reverts back to the previous
calibration values and signals a calibration fault. The
calibration fault can be cleared by activating the
magnetic switch for one second or by performing a
successful calibration.
The calibration process can fail for the following
causes:
• Zero is out of range
• Span is out of range
• Time-Out.
The time and date of calibration events are logged in
non-volatile memory along with the calibration outcome.
Possible calibration scenarios include the following:
• Successful Calibration
• Aborted Calibration
• Failed Calibration and the Cause
The Sensor Module stores calibration data in non-volatile
memory to allow the sensor to be calibrated off-site and
installed in the field without the need for re-calibration.
Calibration Step
Yellow LED
Waiting for Zero
Steady
Waiting for Gas
Blinking
Waiting for Span
Blinking
Remove Cal Gas
Off
Table 5— LEDs During Calibration
