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
59.0in. 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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