This is a customer field-calibration validation device for the CS120A or CS125. It comprises of a ground glass disk mounted in an anodised aluminium 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 CS120A/CS125 and is easy to use.Read More
It functions by scattering a fixed amount of light from the transmitter towards 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 about 150m. The high grade calibrator has a very low temperature coefficient.
The CS120A and CS125 command structures allow a recalibration in the field but usually all that is required is a simple check.
The calibrators are themselves calibrated against a master disk at Campbell Scientific in the UK. This in turn has been calibrated against a standard visibility sensor.
In addition the calibrator comes with 2 calibration bungs. These are put into the sensor hoods to completely block all light reaching the detector thereby simulating a perfectly clear atmosphere.