Preparing For Installation - Priva Compass Installation Manual

Preparing for installation

Determining the location for weighing platforms and weighing indicator
It is desirable to set up the Groscale at the location before the start of a new crop. However, it is
possible to set up the weighing platforms in an existing situation.
First and foremost, you need to determine the location where you want to take the weighings. This
location should be a representative spot in the middle of the crop. When using an unit with four
weighing platforms (2 x 2 weighing platforms), one unit should be placed on the left and the other
on the right of the row of crops in the same section. This way an average value is obtained for the
slab weight of plants on the sunny and the shadowy side of the row of crops are taken into account.
This is because of differences in transpiration. With a V-system, the weighing platforms can be placed
one after the other and the weighing indicator in the middle.
When determining location, the following conditions should also be met:
• The total weight resting on top of the weighing platforms from the support frame, the drain
troughs, subsurface boxes, plants and saturated slabs may not exceed the capacity of the
weighing unit. This is 100 kg (2 weighing platforms 50 kg), 200 kg (2 weighing platforms 100 kg
or 400 kg (4 weighing platforms 100 kg).
• Preferably, the weighing unit should be placed in the valve section which also contains a box to
measure drainage. Dosage and drain measurement can be compared, which gives a surplus
value because the effect on the moisture content can be determined.
• Every weighing platform has a maximum cable length of 5 metres. Therefore, you should bear
in mind that the maximum distance between weighing platform and weighing indicator cannot
exceed 3.5 metres (1.5 metres will be lost on the distance between soil and weighing indicator).
• Weighing platform should not be placed underneath a gutter, because condensation water could
drip off the gutter onto the slab and because the gutter could overflow after heavy rainfall.
• Place the weighing platforms sufficiently high that they remain dry and no water collects
underneath the weighing platforms. This could damage the electrical parts and cause corrosion
over a long period of time.
• Make sure that the higher part of the weighing platform does not get too close to the tubular
heating system or any other source of heating. The radiated warmth could affect the sensor in
the weighing platform and therefore affect the measurement itself.
• When using CO₂-hoses, you need to make sure that these have no discharge openings at the
location where the weighing platform is installed. The waste gases will warm the sensor in the
weighing platform and affect the measurement.
• Preferably, do not suspend CO₂-hoses over the weighing unit, since condensation drops could
fall onto the slab.
• Slab heating should be led around the weighing unit so that it is not accidentally included in
measurements. Due to the way the weighing unit is installed, the slabs do not lie on the cold
floor; therefore slab heating will be superfluous in most cases.
• Please decide whether you want to set up your substrate slabs on the same level with your other
slabs or whether a difference in height is acceptable (maximum 15 cm difference). When using
a countersunk configuration for the weighing platforms, it is necessary to ensure good drainage.
In addition, it is necessary to dig a groove in between the two weighing platforms, for the support
frame and/or the subsurface box.
Configuration of substrate slabs
Below you will find a number of examples of substrate slabs and an indication of the weight of an
unit with a saturated slab.
Possible layouts for slabs 2 x (133x20x7.5 cm)
Rigid boxes which are placed directly onto the weighing platforms without support
frame with box position bow.
Boxes which are placed on a drain trough on top of the weighing platforms without
support frame with box position bow.
Boxes placed on top of specially developed support frames.
Installing Priva Compass - 00.014
Groscale
weight saturated slab
41 kg
48 kg
55 kg
103