J+J has designed and developed an internal digital positioning system (DPS) that provides accurate modulating function to control the movement of the actuator with a 4-20mA or 0-10VDC control signal.
Any change in the control input signal results in a corresponding and proportional change in the position of the actuator.
J+J’s DPS system can be retrofitted to standard J3 on-off actuators. The self-calibrating system provides an output signal as standard, and virtually eliminates ‘hunting’.
An internal microprocessor on the DPS circuit board digitally monitors the analogue input and output signals and compares them to the physical position via an output shaft feedback system, moving the actuator as required to balance the signals.
Digital control ensures high sensitivity and repeatability, with all the usual positioner characteristics such as hysteresis, linearity and precision coming in at under 1%. On initial start-up or on restoration following a power cut, the DPS system will go through a short automatic set-up sequence.
In situations where the actuator is used in manual mode and put back into automatic mode with the actuator out of its normal operating quadrant, the DPS will auto-adjust back into the correct quadrant, re-set itself, and be ready for use again.
The DPS can be supplied as a retro-fit kit containing all the parts required to convert a standard on-off actuator to a modulating unit, and can be used in conjunction with the J+J BSR kit to produce failsafe modulating functionality.
The J3 series multi-voltage actuators are available from Air & Hydraulic Systems