A digital positioner is used to control and operate an AC electric valve actuator. A valve interface control program (ICP) provides a PC-based interface to the valve positioner or positioners. The ICP allows parameter modification, monitors alarm conditions, and provides a display of calibration data. The positioner has a security code to prevent unauthorized access; adjustable independent valve open and close ramp times; electronic valve actuator travel limits; programmable setpoint direction; programmable signal split range; manually adjustable deadband and an auto-adjusting setting; and high positioner resolution. The ICP can command the positioner to do the following: set the value of a specified parameter; read the value of a specified parameter; control the positioner setpoint from a remote computer; request the positioner to return the present status; read the byte value in a specified EEPROM location; set the value of a specified location in EEPROM memory; and select system operating mode.