Pressure Sensor Calibration

The pressure sensor measures a current signal, which is passed on to the spraying computer. This current signal corresponds to a specific operating pressure. Pressure sensors are available in 0-20 mA and 4-20 mA versions, with a corresponding operating pressure of 0 - 25 bar. The type is indicated on the pressure sensor.

Both the minimum current value and the maximum measuring value of the sensor (pressure) must be calibrated. This can be done automatically (see machine program).

WZ00085,0000159 -19-22SEP05-1/3

The left-hand top corner of the display gives P (= pressure) and the left-hand bottom corner gives REF (reference current signal at 0.0 bar). The standard setting is 0.0. This may be checked as follows.

Check that the machine is absolutely pressureless at the location of the pressure sensor (if necessary, temporarily open boom sections with machine in switched off condition). Activate automatic calibration of the reference values by pressing the "+" and "-" keys simultaneously. The left-hand bottom corner of the display gives "MES" (to indicate that current is being measured) and in the right-hand bottom corner a counter counts from 0 to 9 to indicate that current consumption at 0.0 bar is now being measured. The measured reference value is displayed. Press the "PRO" key to confirm the value in the display. The zero value of the pressure sensor is now properly calibrated. The display should now give 0.0 bar (A). If this is not the case, repeat the automatic calibration or increase the P-REF value by 0.1.

WZ00085,0000159 -19-22SEP05-2/3

The left-hand top corner of the display (A) gives P (= pressure) and the left-hand bottom corner gives HI (maximum pressure measuring value). The standard setting is 25.0. The maximum measuring value of the pressure sensor may be checked as follows:

• Activate automatic calibration of the pressure sensor maximum measuring value by pressing the "+" and "-" keys simultaneously (master shut-off valve closed). The spraying computer shows data in the display (B).
• The pressure given in the left-hand top corner of the display is the pressure for calibration of the maximum measuring value. This value can be changed with the "+" and "-" keys. It is recommended to set the maximum pressure of the nozzles used.
• Connect a calibrated pressure gauge to the spray line (preferably in the centre of the spray boom).
• Start the machine and use the "+" and "-" keys (in manual mode) to set the calibration pressure on the pressure gauge (e.g. 5 bar) during spraying (hence with opened master and boom section valves). Perform the calibration on the nozzles used most frequently. After opening the master shut-off valve, the current pressure sensor measuring value (mA) is continuously displayed in the right-hand top of the screen (C).
• Press the "PRO" key to confirm the calibration. The left-hand bottom corner of the display gives "MES" and in the right-hand bottom corner a timer counts from 0 to 9. The current measuring value (mA) belonging to the pressure setting (e.g. 5 bar) is continuously displayed in the right-hand top of the screen (D).
• Finally, the maximum pressure of pressure sensor (E) is automatically calculated.

WZ00085,0000159 -19-22SEP05-3/3