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CST 117/M Test System

Test System CST 117/M for dusting solar cell modules according to VDI 3956-1

The test system CST 117 serves laboratory testing according to VDI 3956 (Test method for the dust soiling behaviour of solar energy systems).
CST 117 Soiling Tester, front view
CST 117 Soiling Tester, front view
This includes tests on the behaviour of glass surfaces under the influence of dusting, changing air humidity and glass temperature and the resulting condensation effects as well as cleaning by wind.

Experiments on other test specimens exposed to these environmental conditions are also possible.


VDI 3956-1
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  • adjustable angle of the sample holder
  • selectable dust dosing positions
  • data logger
  • largely automated processes
  • optimised handling


  • tests according to VDI 3956
  • temperature-dependent dusting and cleaning tests of other types of samples

The test specimen is mounted on a sample holder in an air lock and then drawn into the preconditioned main chamber. The air lock prevents the dust-containing atmosphere from entering the environment. The desired angle of the specimen is set (up to 60° to the horizontal). The environmental scenarios to be investigated are imitated using the following equipment:

- dusting using generator SAG 410/L (Topas) with dual-positionable nozzle
- temperature control of sample holder: with heating mat/cooling unit
- blowing off the sample using a movable air blade

When air is introduced into the chamber by dust dosing, humidification or sample cleaning, a negative pressure must be present in the chamber to prevent the emission of dust into the atmosphere.

Parameter titleUnitValue
air flow velocity m/s ≤ 15
dimension of test specimen mm thickness ≤ 10
specimen holder - base area 200 mm × 200 mm; setting angle 0 ... 60 ° (diskret)
test conditions - environmental temperatur, relative humidity (controlled)
operating medium, gas/air - compressed air supply bar 6 ... 10 (qualitiy class ISO 8573-1:2010 [6:4:2])
power supply - 3 - TN-C-S Netz/PEN; 400 VAC, 50 Hz
test chamber, dimensions mm 700 × 720 × 700
aerosol generation technology - dust disperser SAG 410
power consumption W max. 6000
noise emission dB(A) LpA ≤ 76,7 ± 1,5
dimensions (w × h × d) mm 2107 × 890 × 1647
weight kg approx. 450 (including devices)