Harris Instrument GPX - Guiding and Control Processing Unit


The Model GPX –Guiding Process Controller– from Harris Instrument represents a line of versatile, cost effective, process controllers for use with Scan-A-Line sensors. These processors provide several types of control outputs for the purpose of guiding and controlling processes monitored by any of our proprietary scanned LED sensor solutions. The GPX can provide analog, pulse width modulated error correction signals at currents as high as 14.6 Amps for direct control of electric actuators or hydraulic proportional control valves in order to perform a wide range of guiding and position control processes without relying on a separate controller, such as a PLC. In different configurations, the GPX can even accept analog or digital input signals from some third-party sensors and encoders. Available configuration levels include:

  • Level One: This controller can accept input signals from one or two analog position sensors. It provides a Pulse Width Modulated, positive or negative error correction signal, which can be optionally configured to directly control hydraulic proportional valves or high-current electric actuators or mandrel position controls. There is also an Operator Offset control and and Error Gain control inside the front panel.

  • Level Two: Can be used in more complex guiding applications. There are additional inputs for analogs for Roll or mandrel position, this permits feed forward mandrel position controls and roll position feedback for intermediate guide applications. Can also be configured with PWM to bipolar signal converter to provide an analog signal to a control valve amplifier.

  • Level Three: Can directly accept digital inputs from one or two Scan-A-Line 10XAS-series sensors. Also adds a GUI software Setup Wizard, which permits simple configuration of the processor for a wide variety of sensor configurations and control applications, then stores setup information in onboard, nonvolatile memory. Also adds a Fail Safe set of fail safe relay contacts to allow the GPX to automatically take action in the event of a system malfunction, before it can effect line operation.


  • HP1 power output option: Provides a pulse width modulated (PWM) control signal with 24 Volts at up to 6.5 Amps.

  • HP2 power output option: Provides 24 Volts PWM at up to 14.6 Amps current, for larger actuators.