Tank Sensor Calibration

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Sensor Calibration - Tank

The "Tank" calibration menu can be entered via the drop down menu in the field "Sensor to Calibrate". It will show the current settings for the items listed below.

Three tank levels have to be calibrated for each new machine (tank pressure sensor):

  • Tank Empty level
  • *Tank at Minimum Level (40 liter)
  • *Tank at Maximum Level

*The minimum and maximum tank levels are factory programmed in factory settings. See also "Tank Configuration" in "Factory Settings".

The tank level sensor is a pressure sensor fitted in the bottom of the tank and measures the pressure of the liquid in the tank above the sensor. This value is then used to calculate the actual tank volume. The tank pressure sensor is a very accurate and sensitive

sensor. The sensor has a working range from 0-250 mbar with a corresponding output of 0-20 mA. The analog current signal is converted into a digital value by a 10-bit converter (ADC value between 0 to 1023). Each tank pressure sensor needs to be calibrated.

Tank Empty Cal. [ADC] this ADC value is the output of the tank pressure sensor when the tank is completely empty. The value can be between 0 and 300. The value can be entered manually with the numeric keypad, but it is preferable to calibrate this value. Tank at Minimum Level [ADC] this ADC value is the output of the tank pressure sensor when the tank is at minimum level (minimum level is factory set in Factory Settings). The value can be between 1 and 500 and should be at least 2 units higher than the empty calibration value. The value can be entered manually with the numeric keys, but it is preferable to calibrate this value.

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Tank at Maximum Level [ADC] this ADC value is the output of the tank pressure sensor when the tank is at maximum level (maximum level is factory set in Factory Settings). The value can be between 1 and 1023 and should be at least 50 units higher than the calibration value at minimum level. The value can be entered manually with the numeric keys, but it is preferable to calibrate this value (F). Automatic will give access to a screen with calibration possibilities for: "Tank Empty Cal", "Tank at Minimum Level" and "Tank at Maximum Level". Choose the "Next" button to select which. Manual displays a screen with four fields. It is preferred that each be calibrated automatically, apart from "Maximum Tank Volume [l]". Tank Sensor Value [ADC] the actual tank pressure sensor value is shown. Automatic Filling - Offset The filling valve is closed just before the desired tank level dependent on the value (l) set in here.

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Automatic - Tank Empty Cal.

The calibration of the tank pressure sensor at empty level needs to be done as follows:

1. Make sure that the tank is completely empty and the tank sensor must be free of water and completely dry.
2. The actual tank pressure sensor value is shown on the display.
3. Press "CAL" button to calibrate. When the sensor value is higher than 300 ADC, then a calibration error will be given.
4. The screen will return to the "Tank Sensor" menu.

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Tank Sensor - Step 1

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Tank Empty - Step 2

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Automatic - Tank at Minimum.

In this calibration step of the tank level sensor, the tank must be filled to a minimum level, determined by the factory and set in "Factory Settings". The GreenStar 2 sprayer control system will use linear interpolation to calculate the current tank level when it is below this level. Above this level the calibration table is used (Factory Settings).

The calibration of the tank pressure sensor at minimum level needs to be done as follows:

1. Make sure that the tank is filled with water to the minimum level.

This amount of water (40 liters) needs to be measured accurately (e.g. with a calibrated flow sensor or balance) and entered into the tank.


2. The actual tank level sensor value is shown on the screen.
3. Press "CAL" button to calibrate. The sensor ADC value should be at least 2 units higher than the empty calibration value or otherwise a calibration error will be shown.
4. The screen will return to the "Tank Sensor" menu after calibration.

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Tank Sensor - Step 1

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Tank Minimum - Step 2

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Automatic - Tank at Maximum.

The calibration of the tank level sensor at maximum (level is factory set in factory Settings) needs to be done as follows:

1. Make sure that the tank is filled with water to the maximum level:

  • *3540 l for 3200 l tank
  • *4470 l for 4000 l tank

* These quantities need to be measured accurately (e.g. with a calibrated flow sensor or balance) and filled into the tank. Each tank can vary in size due to the manufacturing process.

* The minimum and maximum tank levels are factory pre-programmed in factory settings and depending on the actual tank size. If required these values can be adjusted. See also "Tank Configuration" in "Factory Setup" to enter the actual value.


2. The actual tank pressure sensor value is shown on screen.
3. Press "CAL" button to calibrate. The sensor ADC value should be at least 50 units higher than the calibration value at minimum tank level or otherwise a calibration error will be shown.
4. The screen will return to the "Tank Sensor" menu after calibration.

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Tank Sensor - Step 1

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Tank Maximum - Step 2

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Manual Calibration
Tank Empty Cal. [ADC] this ADC value is the output of the tank pressure sensor when the tank is completely empty. The value can be between 0 and 300. The value can be entered manually with the numeric keys, but it is preferred to automatically calibrate this value. Tank at Minimum Level [ADC] this ADC value is the output of the tank pressure sensor when the tank is at minimum level (minimum level is factory set in Factory Settings). The value can be between 1 and 500 and should be at least 2 units higher than the empty calibration value. The value can be entered manually with the numeric keys, but it is preferable to automatically calibrate this value. Maximum Tank Volume [L] the maximum tank volume of the sprayer can be entered here. This value is used as reset value for sprayers without tank level sensor and as maximum tank volume for calibrating the tank level sensor if fitted. A higher value than the maximum tank volume cannot be entered later by the operator to (automatically) fill the tank. If the tank needs to be calibrated the absolute value needs to be entered. To determine the maximum volume use a weighbridge or use a calibrated flow sensor. Tank at Maximum Level [ADC] this ADC value is the output of the tank pressure sensor when the tank is at maximum level (maximum level is factory set in Factory Settings). The value can be between 1 and 1023 and should be at least 50 units higher than the calibration value at minimum level. The value can be entered manually with the numeric keys, but it is preferable to automatically calibrate this value.
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Tank Sensor Calibration - Manual

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Automatic - Tank Shape Calibration

The input from the tank level sensor has to be converted into a value to determine the actual tank volume. First the tank level sensor has to be calibrated when the tank is empty, at minimum and at maximum level in the menu "Tank Sensor". If this is done, the intermediate steps have to be calibrated with the "Tank Shape Calibration".

The actual calibration of the shape of the tank is done by spraying the tank empty at a constant flow, starting from the "Maximum Tank Volume" until the "Minimum Tank Volume" is reached. The minimum tank volume is used since a constant flow cannot be guaranteed below the minimum level due to air sucking at the bottom of the tank.

The actual calibration of the complete tank must be done starting from a completely filled tank. There are three steps to the process shown on screen. The calibration procedure is as follows:

1. Prepare the machine for spraying in manual mode (at constant PTO speed). The spraying pressure should be absolutely constant (set computer in manual mode). During the calibration process the sprayer should not be moved or touched, otherwise noise signals could be created.
2. Disable the agitation in the tank during the calibration.
3. The circulation valve should be set to "circulation"
4. Ensure that the tank is completely filled up.
5. Press "CAL" button to start the calibration of the tank shape.
6. Start spraying with a constant flow (Master valve switch ON). The unit detects that the Master input becomes active and starts the calibration procedure.
7. The display now will show the actual measured ADC value from the tank level sensor during the calibration process. Below that a message "Tank Shape Calibration is running, Please Wait" will be shown together with a bar graph showing the progress of the calibration.
8. The tank must be sprayed empty (at constant flow rate) until the minimum level is reached.

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Tank Shape Calibration - Step 1

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Tank Shape Calibration - Step 2

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Tank Shape Calibration - Step 3

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9. When the tank is below the minimum level, the calibration procedure stops automatically and returns to the "Tank Calibration" menu.

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