The spectral confocal dark signal is generated by the back reflection (noise) of the optical surface inside the sensor. This signal must be stored in a memory unit that is not easily lost in order to be subtracted from the actual signal measured. The level of the dark signal depends on the sampling rate and LED brightness. Today, the spectrometer spectral confocal manufacturer will talk to you about how the spectral confocal sensor can obtain Dark signals:

The manufacturer picks up the dark signal when adjusting, but must repeat the operation periodically. Recommendation: The dark signal acquisition procedure should be performed at least 15 minutes after the sensor is turned on to ensure that the sensor reaches thermal balance.

The start of the spectral confocal dark signal measurement can be started by pressing the dark button on the front panel of the sensor or by clicking the dark button on the CCS Manager software. More generally, send the "$DRK" command to the sensor.

This operation can take tens of seconds because the sensor continuously measures and stores the dark signal at all preset frequencies. It is very important that there are no objects in the measurement range. It is best to cover the probe with a piece of paper to empty the beam.

Press the "Dark" button on the front panel of the sensor, and the "Strength" and "Measurement" indicators on the front panel will alternately flash green, indicating that the operation is in progress. Keep the probe paper sealed. After the measurement is complete, three LED indicators flash simultaneously, their colors indicating the operation result:

The green obtained dark signal level meets the requirements of all frequencies.

The orange dark signal level is too high at low frequencies, but can be measured at high frequencies.

The red dark signal is high on all frequencies.

The paper can now be removed and the sensor can be used normally.

High dark signal: If after completing a series of dark signal acquisition, the flashing LED is orange or red, it means that the obtained dark signal is too high. In this case, it is not possible to set the sensor to scan at a low frequency. If the problem persists, please consult the riser.

Adaptive DARK: CCS sensors have an operating mode (adaptive dark signal mode) where the dark signal is constantly updated.

Now, do you understand how spectral confocal sensors acquire Dark signals? If you have questions or do not understand, you can call to consult the spectrometer spectral confocal manufacturers. More information can continue to follow the official website of the instrument.