Optical Sensors / CS140 Calibrator
CS140 Calibrator CS140 Calibrator
Traceable Background Luminance Calibration
weather applications supported water applications supported energy applications supported gas flux and turbulence applications supported infrastructure applications supported soil applications supported


The CS140 Calibrator is a high-quality device to generate a known luminance level for calibrating a CS140 Background Luminance Sensor. It is powered from the CS140 supply and is used while in communication with it.

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Benefits and Features

  • Type certified for Aviation use by the German Meteorological Service, Deutscher Wetterdienst (DWD)


Technical Description

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.


CS140-OS Release 10 v.10 (53 kB) 09-03-2021

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:

  • Bug fixed relating to the main serial communications baud rate and particular versions of CPU silicon.
  • Timing bug in RS485 fixed to improve compatibility with certain RS485 interfaces.

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