Model 531 X-Y Optical Position Indicator

When interfaced with continuous or segmented position sensing detectors, the Model 531 determines the location of the centroid of an incident light spot, and displays its X-Y position both digitally and graphically. This position information may then be transferred by computer over a built-in IEEE-488 interface.

The Model 531 contains an analog preamplification section, and a digital processing and I/O section. The analog front end is isolated from the digital section by an electrically shielded enclosure within the 531’s housing. This shielded section can house two analog cards which plug into the back panel. The analog amplifier stage operates in the transimpedance mode to boost the photodetector current and convert it to a voltage. The digital section is essentially a microcomputer based on popular bus architecture. It controls an A/D converter which digitizes the voltages from the analog section, and then performs the calculations shown, displaying the results on the dot matrix display. The microcomputer also adjusts the analog gain, controls modulated operation of light sources, and controls the IEEE-488 functions.

For stand-alone operation, the Model 531 is programmed through a tactile touch panel beside the display. The touch keys prompt you through several programming menus for simple setup. The menus let you select the type of detector in use, calibration and scaling factors, and pulsed or DC operation. You can also program the Model 531 via the IEEE-488 interface and remotely control your measurement.

UDT Instruments provides optional LabWindows® compatible drivers for easy interfacing with Windows PCs.

The unit provides a 100 mA current source to drive an LED in either DC or pulsed mode. Optionally, a second analog card can be plugged in to permit the operation of a second dual axis position sensor (or 2 more single axis devices). Two sensors provide "depth" perception for 3-D position sensing.

The Model 531 is compatible with all position sensors including duo-lateral, transparent duo-lateral, single and dual axis tetra-lateral, pin-cushion types, and bi-cell and quadrant detectors. The instrument comes in a 19" rack-mountable case. An instruction manual and power cord are provided.