How are electric actuators tested after leaving the factory?

After production, electric actuators must undergo formal testing. First, while the unit is unpowered, manually adjust the actuator mechanism to the midpoint position and switch the operation mode to "local." Next, apply power and observe whether the actuator's direction of travel aligns with the valve's direction of movement; if they do not match, the power supply phases must be swapped.

Then, adjust the limit switches. Move the valve to the fully closed position, set the multimeter to continuity (buzzer) mode, and check if the "close limit" contact has switched from normally open to normally closed; a closed contact indicates the correct setting. If it has not closed, continue adjusting the close limit switch until the correct position is reached.

After calibrating the fully closed position, calibrate the fully open position. First, verify that the "open limit" signal is correct; if not, adjust the open limit switch. Once both limits are calibrated, cycle the electric valve back and forth a few times to ensure the signals are normal. Next, calibrate the feedback signal. For electric actuators, the accuracy of the feedback current is crucial as it directly affects the control signal; therefore, the feedback current must be precise.

To calibrate, set the multimeter to the mA range and connect it in series within the feedback loop. Move the actuator to the fully closed position and observe the feedback value on the multimeter; a reading of 4mA indicates the correct setting, while any other value implies a deviation requiring recalibration. Use the "zero" potentiometer to adjust the feedback value to the correct level. Then, switch the actuator to the fully open mode; a reading of 20mA is normal here. If the reading is incorrect, use the "span" (full-scale) potentiometer to adjust the feedback value to 20mA. Repeat this back-and-forth adjustment process until the readings are within acceptable limits.

Finally, switch the electric actuator to "remote" operation mode. Use a signal generator to input a 4mA signal and verify that the valve moves to the fully closed position. Then, input a 20mA signal to check if it reaches the fully open state. Input various corresponding values ​​and compare the feedback values ​​with the input values; if the discrepancy is significant, repeat the calibration steps until the performance meets specifications.