All technical instruments have a risk to gradually deviate from their standards over time. This process is known as drift. In conventional (wet chemistry) laboratories drift is managed by measuring blank samples (i.e. solutions with a known concentration) in between measurements and repeated adjustments of the calibration lines. The methods have to be adjusted for sensor technology, in order to ensure that we can detect possible drifts between our sensor instruments. At AgroCares we manage drift between sensor instruments using calibration caps.
Calibration caps have a known spectral signal and are measured when the Scanner is switched on and in between measurements. If drift is detected, a complex algorithm automatically corrects it. The calibration cap comes with the Scanner and the calibration takes only a few minutes.
Cleaning the scanner
The SoilCares Scanner is a Near infra-Red (NIR) measuring device. Proper care of the sensor head is needed to ensure a good performance of the device. Therefore, the bottom needs to be kept clean at all times by using the cleaning cloth and the brush. This is to prevent re-analyzing remaining soil of the previous sample. The EC probes (No 5), temperature probe (No 3) and glass window (No 4) need to be kept clean between every soil sample scan. Preferably between scans of the same soil as well. A clean scanner produces the most reliable results.
How to clean:
- First clean the probes and the window with the black brush (delivered with the scanner).
- If needed (for example when scanning clay soil) clean the bottom of the scanner and the glass with a paper towel or moist cotton towel. Be careful not to scratch the surface of the window, scratches can influence the reliability of the scan. When the scratches on the glass are too severe then scans will be rejected and a replacement of the glass window is needed.
Cleaning the calibration cap
The calibration cap is used to maintain a high performance of the scanner. The white side (no 7a) of the cap needs to be kept clean (white). The yellow side (no 7b) needs to be kept clean and dry. It is not possible to clean the yellow side of the cap. Moisture will damage the yellow surface. If the calibration cap is not properly maintained then a replacement of the cap might be necessary. Therefore it is important to keep the scanner clean before it is placed on the calibration cap
How to clean the calibration cap:
- The white side can be cleaned with a bit (drop) of an abrasive cleaning product and a drop of water. Be careful that the yellow side is not getting wet. The material of the white side absorbs water, therefore drying takes several hours before the cap can be used again. The cap can be dried on the heater. An error message will pop up in the app when the white is not completely dry.
- The yellow part cannot in any way handle water. Additionally, the yellow part is made out of fiber material which can’t be brushed. Therefore, it is nearly impossible to clean the yellow side of the cap. It is important that the sensor head of the scanner is always completely clean before being placed on the calibration cap.
When the white is not completely white anymore or the fibers of the yellow set loose, then the calibration cap will not be accepted by the program anymore. A replacement of the cap is needed. A new calibration cap can be ordered via our webshop. order here