The calibration is made by using high-quality LEDs to produce a known light level, white, with a value of 4500 cd/m2. The light has a flat spectrum so the calibration is valid over the CIE spectrum sensitivity of the CS140 itself. The LEDs illuminate a diffuser, which itself illuminates the CS140 under calibration. An on/off switch turns off the LEDs and allows the unit to provide a zero check. Each unit is individually calibrated, and the value of luminance it produces is put on a label on the unit. This calibration is traceable, and this value is used in the calibration process.
Generated light level | About 4500 cdm‾² (individually calibrated) |
Accuracy | 5% |
Operating temperature range | 0 to 40°C |
Dimensions (excluding cables) | 72 mm long x 46 mm dia |
Weight | 300g approx |
Communications | RS 232, 38400 Bd communication with CS140 and laptop |
The 34295 calibration device is only compatible with the CS140. Although the CS125 and CS120A have a similar device, these devices are not interchangeable.
Release Note for Operating System OS10 for the Campbell Scientific CS140 Background Luminance Sensor
Campbell Scientific has introduced a new operating system, OS10, for the CS140 background luminance sensor. It is fully backwards compatible and is easily installed on all CS140 sensors. OS10 is available free of charge and can be downloaded from the Campbell Scientific website or supplied by email on request. Functionality, including data message formats is unchanged.
Main improvements: