How-To: 3725 Positioner Calibration (240/350 cm² - Fail Close)
Step by Step Instructions:
- After the positioner has been correctly mounted, apply a 4-20 mA signal to the positioner. Attach the positive lead to terminal 11, and the negative lead to terminal 12.
- After connecting the electrical signal, the positioner performs a brief self test which takes approximately three seconds. During this time, do not touch the key panel.
- For actuator sizes smaller than 240 cm², it is necessary to adjust the volume restriction to the “Minimum” setting.
- We’ll begin the calibration process by entering the air action. Using the capacitive touch keys, press the “up” arrow and proceed to parameter 2. We would like the valve to open as the signal pressure increases, therefore we can leave the setting at Air-To-Open… shown on the display as “A-T-O”.
- Next, we’ll confirm the pin position is set to 35 at parameter 3, matching the pin position on the lever.
- Parameter 4 is used to define the travel, in our case 15mm. Press the “*” key, set the travel to 15 mm using the “up” arrow, and then press the “*” key again.
- By default, the positioner is configured for increasing/increasing operation. This is set at parameter 7, and can be confirmed with the two “right arrows” on the display.
- For most applications, the positioner is now ready for initialization.
- Proceed to parameter 15, and hold the “*” key while the timer counts down. Release the key when the display show “INIT”, this begins the calibration process.
- The positioner will take a few minutes to perform the calibration. Once completed, the display will show the relevant travel position based on the 4-20 mA input signal.