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The HART Communicator now
requests that the level float be
set to the desired level upper trim
point. The second trim point can
be any other level point but it is
recommended that this point be
as far away from the zero point as
possible. When the float is at this
position, the transmitter will always
report the digital value entered in
the user chosen units. The user
must press OK when the float is at
that position.
The transmitter will take several
seconds to insure that the level
signal has stabilized. Once
the measurement is stable, the
procedure will continue without
user intervention. The HART
communicator will then send
the command to the transmitter
to calculate the new Level gain
calibration constant.
The HART Communicator will now
request the user to enter the value
at the high trim point. The HART
Communicator will display the
last upper trim point, for example
60 in, and the user will enter the
new upper trim point, for example
59.0 in. The HART Communicator
will now send this value to the
transmitter.
When the transmitter has completed
its calculation of the new Level gain
calibration constant, it will reply to
the HART Communicator. Then the
HART Communicator will inform the
user that the level upper trim point
has been trimmed. Then the HART
Communicator will inform the user
that the upper level trim point has
been trimmed.
The user is then notified that
the loop may now be returned
to automatic control. After the
user presses OK the HART
Communicator returns to the
Calibration screen.
The HART Communicator is now at
the starting screen for the Full Level
Trim.
Zero Temperature Trim
Starting at the Calibration screen,
select the Zero Temper Trim
procedure. This procedure trims
the Temperature digital value
measurement at the reference value
of the RTD (1000 ohms).
If the user selects Zero Temper
Trim from the Calibration screen,
this screen will appear reminding
the user that the loop should be
removed from automatic control
before proceeding. When this has
been done, the user must press OK
to continue.
This screen warns the user that
proceeding will affect the sensor
calibration. The user must press
OK when ready to proceed.
The HART Communicator now
requests that the temperature
be set to the desired 0 deg C
temperature point. If using a
temperature simulator, adjust the
simulator temperature to 0 deg C
or if using a resistance box, adjust
the resistance value to 1000 ohms.
The user must press OK when the
RTD or simulator is at the required
value.
The transmitter will take about
fifteen seconds to insure that the
temperature signal has stabilized.
Once the measurement is stable,
the procedure will continue without
user intervention. The HART
communicator will then send the
command to the transmitter to
calculate the new Temperature zero
calibration constant.
When the transmitter has completed
its calculation it will reply to the
HART Communicator. Then the
HART Communicator will inform the
user that the zero level point has
been trimmed.
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