Operating Principle
The object to be gauged or inspected is viewed by the HVS sensor through an optical lens. Brightness variations in contrast (grey levels) between the object and the background are converted to electrical signals by a linear CCD, with each of 256 pixels along the field of view outputting 1 of 256 grey levels. Edge positions (up to 18) and widths or centers (differences or midpoints between any two edges) along the pixel array are calculated by the computer and output in state, analog, or digital format. Special proprietary computer algorithms provide edge measurement accuracies of 1/1000th of the field of view with exceptional insensitivity to ambient lighting changes. Preprogrammed software options provide a wide range of measurement function. During setup alignment, an internal light projects onto the inspection part, coincident with the area seen by the CCD. The LED bar graph provides visual verification of part location and measurement data; it also aids in the alignment and focus setup procedure. For all models, the configuration and measurement modes of the gauge are sent to the HVS via a computer.

Communications
All models of the HVS have one of two variations of serial communications channel: RS232C or RS422 partyline software addressable. The RS232 version communicates directly with personal computers via their serial ports. This is the normal communications version for those applications where the communications port will be used only to configure the gauge and the discrete state or analog output will be used in the process. Up to 10 partyline software addressed models can share a communication port in which each unit is addressed by sending its serial number preceding any command to the gauges.