The Model EVA-1 consists of a microprocessor-controlled, linear stepper motor that responds to an input signal of 4…20 mA DC. It also has an optional isolated loop powered 4…20 mA position output for signaling back to an indicator or control panel. The standard Model EVA-1 requires a 115V AC power supply with 230V AC and 24V DC models available. A stroke of 0.437 in. (11 mm) for the 1/4 in. (6 mm) unit or a stroke of 0.562 in. (14 mm) for the 1/2…1 in. (12…25 mm) units is standard and can be adjusted quickly and easily with two switches under the actuator cover or via the communication port. This ease of calibration can be used to split the range of the input or limit the up or down travel of the valve. The unit uses a dual-speed operating mode. The low speed mode generates high thrust for seating the valve and overcoming packing friction while the high speed mode allows the valve to respond quickly to large input signal changes.