38
TruckWeigh™ Calibration
Process
Please read and understand the entire calibration process
before proceeding.
Prerequisites
Calibration should only be carried out after all previous steps
of installation and setup have been successfully completed.
It should ideally be done on flat, level ground on a calm day,
even indoors if possible.
It is essential that the calibration process is carried out in
a specific order that will be detailed in this manual,
summarized as follows:
1. Zero Inclinometers
Sets the reference point for the Junction Box and
TruckWeigh™ Axle Transducers, completed with
an empty payload.
2. Zero
Sets the tare point for the system, completed
with an empty payload usually immediately after
Zero Inclinometers.
3. Axle Spans
Sets the Span point for the system, completed
with a full payload, ideally as close to GVWR as
is possible.
Weighing the Vehicle
Calibration requires that each of the individual axles of the
vehicle be weighed. The process is the same when empty or
full. This can be achieved using either of two methods:
1. Weigh Pads Method
Ideally 1 pair of weigh pads per axle is required, i.e. 2 axles:
4 weigh pads, 3 axles: 6 weigh pads, etc.
If only 1 pair of weigh pads is available leveling mats should be
used under all other un-weighed axles in order to maintain the
overall level of all axles.
Very Important:
If using weigh pads, the axle figure is calculated by adding
together the readings from
both
weigh pads beneath that axle.
Note:
The Weighbridge must have a level approach. This would
normally mean a pit type weighbridge as shown opposite:
2. Weighbridge Method
The measurement of each axle on a weighbridge can be done
by driving the vehicle on or off the weighbridge one axle at a
time and noting the readout in each case. The weight for each
axle can then be calculated by simple subtraction of each
previous figure as shown in the example below (this will vary
depending upon the number of axles).
Payload
Axle Spans
Empty
Full
= Full - Empty
Weighbridge
Axle
Weighbridge
Axle
Vehicle Weight
W
9000
W
2
18000
Axle 1
A
7500
E
=W-A
1500
A
2
15500
E
2
=W
2
-A
2
2500
1000
Axle 2
B
6000
F
=A-B
1500
B
2
13000
F
2
=A
2
-B
2
2500
1000
Axle 3
C
3000
G
=B-C
3000
C
2
6500
G
2
=B
2
-C
2
6500
3500
Axle 4
7500
C
3000
C
2
6500
3500
9000
Total
18000
9000
Fig 3.01
Fig 3.02
Fig 3.03
SI Onboard TruckWeigh™ Manual
Calibration
Summary of Contents for VPG On-Board Weighing SI Onboard TruckWeigh
Page 5: ...5 Installation SI Onboard Installation SI Onboard TruckWeigh Manual Installation ...
Page 23: ...23 Setup Setup SI Onboard TruckWeigh Manual ...
Page 36: ...36 Installation SI Onboard SI Onboard TruckWeigh Manual Setup ...
Page 37: ...37 Calibration Calibration SI Onboard TruckWeigh Manual ...
Page 42: ...42 SI Onboard TruckWeigh Manual Calibration ...
Page 43: ...Appendices Appendices SI Onboard TruckWeigh Manual ...
Page 58: ...58 SI Onboard TruckWeigh Manual Notes ...
Page 59: ......
