Priva Compass Installation Manual page 110

Priva
Calibrating slab (weight of dry and saturated slab)
In order to register the most accurate weight in the process computer, it is necessary to match the
output range of the analog output as closely as possible to the maximum nett weight to be weighed.
For this, the dry weight and the weight of the saturated substrate slab should be recorded after
which the output range can be set in the menu Service, menu item Max #kg/5V on the basis of the
saturated slab weight. This can be entered by using the menu Slab calibration .
If a weighing platform carries a dry substrate slab witdry plant pots, the weighing unit can be tared.
The following procedure should be performed:
1. If necessary, put the empty subsurface box(es) on a drain trough or a support frame. Add the
dry slab and place the dry plant pots on the weighing platforms.
2. Go to the Slab calibration menu.
3. Deactivate the menu protection by pressing "Enter" followed by " ↑ " and hold this key combination
down for 3 seconds. <<MENU>> will change to >>MENU<<.
4. Press "Enter" to activate the menu.
5. The display now shows Set tare Weight and it shows the current nett weight. Press "Enter" to
indicate that the Set tare Weight function is to be performed. The brackets on either side of the
weight will change direction to >> <<. Press "Enter" again to set the measured value to zero.
6. Press "Esc" to leave the menu and to reactivate the menu protection.
7. Saturate the slab fully. Place the plant pots - which have been moistened as well - onto the slab.
The slab should not be allowed to drain. If the slab is not fully saturated you should proceed
with this setting procedure and adjust the range at a later date by means of the Service menu
(Please refer to "Setting output range and adjusting slab calibration data at a later date").
8. Go to the Slab calibration menu.
9. Deactivate the menu protection by pressing "Enter" followed by " ↑ " and hold this key combination
down for 3 seconds. <<MENU>> will change to >>MENU<<.
10. Press "Enter" to activate the menu.
11. Press the "↓" key once.
12. The display will now show the text Saturated Slab and it shows the current nett weight. Press
"Enter" to indicate whether you want to adjust the setting. The brackets surrounding the displayed
weight will change direction to >> <<. Press "Enter" again to record the displayed weight in the
weighing indicator.
13. Press "Esc" to leave the menu and reactivate the menu protection.
In order to calibrate the unit in one day, moisture should be dripped onto the slab until this
is saturated and a number of similar slabs and subsurface boxes should be kept aside for
taring purposes.
Setting output range and adjusting slab calibration data at a later date
If you have not used the dry or saturated slab for calibration purposes during the calibration process,
you will still be able to enter the weight of an empty or full slab (or an estimate of these) manually
by using the Service menu. The output range of the analog output 1 to the process computer can
also be set here.
1. Go to the Service menu.
2. Deactivate the menu protection by pressing "Enter" followed by " ↑ " and hold this key combination
down for 3 seconds. <<MENU>> will change to >>MENU<<.
3. Press "Enter" to activate the menu.
4. The display will show the text Set tare Weight . Press "Enter" if this weight is to be adjusted. Here
the weight of an empty unit has to be entered. This will usually equal the weight of the support
frame including substrate slabs and subsurface boxes. This weight will be used as the new zero
weight in relation to the absolute zero point of the weighing indicator.
5. Use the arrow keys to set the weight of a dry slab and press "Enter" to confirm.
6. Press the " ↓" key.
7. The display will now show the text Saturated Slab . Press "Enter" if this weight is to be adjusted.
8. Set the weight of the saturated slab using the arrow keys and press "Enter" to confirm.
9. Press the " ↓" key.
108 Installing Priva Compass - 00.014