Harris Instrument Scan-A-Line has established a position of leadership in web guiding and strip guiding applications.Â The diversity of these applications has created a demand for a more versatile guide controller to interface with a wide variety of position sensors and many different control actuators.Â Versatility often comes with increased complexity that make a product difficult to configure.Â The Scan-A-Line Model GPX overcomes this difficulty with a simple Windows Based GUI that permits easy selection from a wide list of possible configurations.Â Once the setup is used to select Sensor type and size and the configuration as a single or dual sensor guide system, this information is stored in non-volatile RAM and will remain with the GPX as it is moved from one location to another.Â There are no more jumpers to set, pre-processor boards to install, or internal re-wiring as we move from one application to another.Â The Windows PC can be disconnected from the GPX until such time when the configuration must be changed for a new application.Â With this software configuration ability, one GPX unit can be used as a spare for many different units in an installation site.
The GPX Operator interface includes an LED Bar-graph that displays actual web or strip position.Â The bar-graph also displays a flashing segment when excess errors are seen, and a fault indicator when the measurement data may be compromised.Â Under the Bar-Graph display there is a series of Mode Indicators behind a sealed touch panel.Â From this interface the operator can select the operation modes for the GPX.Â In the MANUAL Mode the JOG IN and JOG OUT switch will permit moving of the mandrel or guide rolls.Â If the AUTO-CENTER Mode is selected while in MANUAL, the Mandrel or Guide Roll will move to the center of its range as soon as the AUTO mode is selected.Â Also from MANUAL the AUTO ZERO button can be pushed to establish the present strip position as the target when the AUTO MODE is again selected.Â The GUIDE MODE selector toggles when pressed to select CENTER GUIDE, EDGE GUIDE LEFT, or EDGE GUIDE RIGHT modes.Â Guide mode must be selected while in MANUAL and will take effect as soon as AUTO is selected.Â Of course the GUIDE MODE selector will only operate when two sensors are installed but the GPX can guide with a single sensor when that is how it is configured in the set-up GUI.Â The ability to select one edge of the strip or web for guiding permits good control when one of the strip edges is damaged.
The Model GPX can supply control signals to a variety of actuators.Â The primary output mode as a Pulse Width Modulated (PWM) control signal that can be used to control proportional hydraulic steering valves.Â In this mode the control signal looks to the valve like a +/-10 Volt analog control with plenty of reserve current available.Â This same signal can be boosted with an optional built in power supply to supply +/-24 Volts to directly drive an electric actuator.Â In the case where the proportional control valve must drive an external amplifier, a digital to analog converter is included to eliminate the PWM feature which will confuse the servo amplifier.
The following is a list of some of the common web guide or strip guide application appropriate for the Scan-A-Line Model GPX.
- Â Single Sensor Edge Guide or Center Guide from an analog (Level 1) or digital (Level 2) position sensor.Â The Scan-A-Mizer and Model EG-30 analog sensors from Scan-A-Line are compatible with Model GPX,Â as are analog sensors from some 3rd party suppliers.Â The Digital sensors include the Scan-A-Line 10X-AS Series and 10X-BR Series.
- Â Â Dual Sensor systems can be Analog (Level 1) or Digital (Level 2) position sensors.Â The Digital Scan-A-Line 10X-AS series and 10X-BR series will both work with the Level 2 Model GPX.Â The 10X-BR series sensors are pass-line independent and can be used to edge guide or center guide a strip with a wavy edge or moving pass-line.