1 (2019-12-14 22:59:54 отредактировано Mechatronica)

Тема: How to make a calibation of axle load sensors

We have a video about full process of onboard weighing system Eurosens Difference installation

https://youtu.be/azj5Zogh9Hk

Calibration tables are stored onboard in that case.
You may ask - how to calibrate sensors only, when we have several axle load sensors connected to GPS tracker.

And we already have some data coming to server, like ain1, ain2 data from sensors.

As usual, we have to get vehicle on truck scales.

2 (2019-12-14 22:45:08 отредактировано Mechatronica)

Re: How to make a calibation of axle load sensors

How to place vehicle on scales depends on sensor installation scheme - we have to put on scales only axle with sensor or only group of axles which is measured by single sensor

Example:
konf1

Some axles are grouped and measured only by one sensor, so whole group of axles should be placed on scales together.

In all cases from picture above we will have 3 (three) calibration tables as result of calibration.

A. Truck is empty.
A.1 Put axle with sensor1 on scales (other axles should not stay on scales!).
Record data from scales (in kilograms or tons) and sensor input value (coming to server, for example, AIN1) in notepad

A.2 Put axle (or group of axles) with sensor2 on scales.
Put axle with sensor2 on scales (other axles should not stay on scales!).
Record data from scales (in kilograms or tons) and sensor input value (coming to server, for example, AIN2) in notepad

A.3 Do same with all installed sensor (axle groups).

B. Add some cargo in vehicle. You don't need to know exact weight. We will use data from scales.
Repeat steps A.1-A.3  and add second point of calibration to all sensor tables in notepad.

C. Add heavy cargo, to close for maximum weight being carried by this truck.
Repeat steps A.1-A.3 and add third point of calibration for all sensor tables.

Note, that in fact all steps can be done during vehicle operation!
Just ask customer drive vehicle to the scales and inform you about scale data. You can always monitor sensor data at server side.

3

Re: How to make a calibation of axle load sensors

As a result you will have tables (dummy data, just for example):

Sensor1:

AIN1 1766    axle load 5400 kg
AIN1 1902    axle load 7600 kg
AIN1 2300    axle load 11200 kg

Sensor2:

AIN1 1566    axle load 5700 kg
AIN1 2102    axle load 9600 kg
AIN1 2400    axle load 13200 kg


Sensor3:

AIN1 1607    axle load 5500 kg
AIN1 1942    axle load 7900 kg
AIN1 2156    axle load 12200 kg

You may add more points to these tables, it will improves accuracy a bit.

4 (2019-12-14 22:55:38 отредактировано Mechatronica)

Re: How to make a calibation of axle load sensors

Now your software can calculate axle loads based on this data.

If your software platform supports calibation table (like Wialon) - fill this data as calibration tables

if your software use "Formulas" for sensor calculation you may need to calculate formula which is corresponds to this table data.

You may use  this spline polynomial generator
http://www.xuru.org/rt/PR.asp

Example:

polynomial gen

Ready formula is marked by red.

Put it into your gps tracking software to calculate axle load based on AIN data.
Calculate all formulas for every installed sensor.

So, each AIN1...3 will be transformed by its own calibration table and converted into Axleload1, Axleload2, Axleload3

5

Re: How to make a calibation of axle load sensors

And last step.
Your software should allow to create new sensor which is calculated as sum of several sensors.

Total vehicle weight=Axleload1+Axleload2+Axleload3

And another sensor : Cargo weight

Cargo weight=Total vehicle weight - Empty vehicle weight

(Empty vehicle weight is a sum of axle loads for empty vehicle)

Now calibation and setting up of your tracking platform are finished.