Model 4500 Premier Dust and Opacity Monitor64B3 Periodic Modes of OperationB3-1 Calibration Check111 2 8 93 6 7 4105TransceiverKey1. Source LED 7. Detector Dr2. Flood LED 8. Concave Mirror3. 50/50 Beam Splitter 9. Span Filter4. Collimating Lens 10. Zero Point Reflector5. Collimated Beam 11. Automatic Fail Safe Shutter (Optional)6. Detector DmThe Transceiver periodically performs a two step calibration check. In the first step, a zero-point reflector(10), mounted within the air purge of the Transceiver is placed into the optical axis. In the second step, thespan filter (9) is also placed in the light path. The monitor reads the difference in light between the currentzero–point and the zero–point established during the last clear stack calibration, and notes this value as theamount of drift and optical dust build-up. The opacity value of the span filter (9) is shown on the calibrationcertificate which accompanies the instrument.CAUTIONDo not attempt to move the zero point reflector by hand. The precision gearbox willbe irreparably damaged.
