28678

The 28678 is a customer field-calibration validation device for the CS120/A or CS125. It comprises a ground glass disk mounted in an anodized aluminum frame, which simulates visibility data for the sensor, allowing verification of the calibration constants held within the system. The calibration device mounts directly to the CS120/A or CS125 and is easy to use.

The calibration device functions by scattering a fixed amount of light from the transmitter toward the detector, thereby simulating scattering aerosols in the sample volume.

Each disk has the calibration extinction coefficient (EXCO) written on it. This is related to visibility by the equation "Visibility in km = 3/EXCO." Typically, the disk simulates a visibility of approximately 150 m (492 ft). The high-grade calibrator has a very low temperature coefficient.

The CS120/A and CS125 command structures allow a recalibration in the field, but typically only a simple check is required. 

The calibrator comes with two calibration bungs. These are put into the sensor hoods to completely block all light reaching the detector, thereby simulating a perfectly clear atmosphere.