How-To: Calibrate a 3730-3 HART Positioner (120 cm², Fail Open)
Step by Step Instructions:
- To prepare the positioner for fail-open operation, slide the "AIR TO" switch to the "CLOSE" position.
- For small actuators such as the 120 cm², it's advisable to restrict the output air volume to approximately 50 %.
- Begin the calibration process by entering configuration mode. Using the rotary push button, turn it until parameter 3 is shown, and push the button. Turn again until the display shows "Yes", and push to accept the change.
- Parameter 4 indicates the pin position and is set to 35.
- Parameter 5 sets our travel, and is kept at 15 mm.
- Parameter 6 is changed to nominal to use our 15 mm stroke rather than the valve maximum.
- The final parameter to set is 7, this is our operating direction and is set to increasing-decreasing for standard fail-open operation.
- Now, go back to parameter zero and press the recessed initialization button to begin the auto calibration process.
- This process can take a few minutes while the positioner adapts itself to this specific valve and it's operating characteristics. It is important not to disturb or interrupt this process until it's finished.
- Once the calibration is completed, the display will briefly show "Tune", and then revert to the position specified by the control signal.
- To confirm correct operation, cycle through various set-points and ensure the valve responds accurately.
- The positioner is now calibrated and ready for operation.