Kistler Group (Indonesia) - WIM sensors allow accurate compensation of coal delivery trucks

A huge mine in Melak, in central Borneo, Indonesia produces more than 7,600,000 tons of coal every year. The coal is transported about 100 km by truck from the mine to the coast. The trucks that are used are 40 m long with one or two trailers, have up to 12 axles and weigh a total of 200 tons. Before unloading, the trucks are statically weighed; the subcontractor is paid for the amount of coal delivered. However due to wet weather conditions several tons of coal can often stick to the inside of the trucks after unloading, with the result that the customer has to pay for coal that was never unloaded.



To tackle this problem the owner of this mine decided to install a secondary weighing sys-tem to determine the actual weight of the trucks after unloading their load. By comparing the weights before and after unloading, the exact amount of coal delivered can be calculat-ed. Because of the huge amount of coal – and money involved – the company required an accuracy of at least 3% for the total weight of the trucks. This measurement accuracy should be achieved at a speed range of 2 – 25 km/h and with axle loads of up to 25 tons.



Kistler suggested using the Lineas® sensors for this new WIM application. The Lineas® sen-sor is a quartz sensor, which measures the wheel as well as the axle loads of vehicles pass-ing under rolling conditions. The sensor is installed in the road surface and provides highly accurate measurement signals. Thanks to the physical properties of the quartz, the Lineas® sensors combine high measurement accuracy with long-term stability and durability. It can be used in a variety of measuring conditions, from low to high speeds, and it is also insensi-tive to temperature variations. The sensors are quick and easy to install in the road surface and are available in 3 different sensor lengths to match all lane widths.

To make sure the high requirements were met, eight, instead of the normal four, Lineas® sensors were installed in a 60-m long concrete platform. Custom-made electronics and software developed by a Kistler partner, were used to maximize the measurement accura-cy. The Lineas® sensors were installed by a local construction company under the supervi-sion of a Kistler specialist. After calibration of the WIM system (using a standard 40 tons truck), the system was launched in February 2013. Finally the system was also tested and certified by the local institute for legal metrology (UPTD Metologi).

Lineas® sensors are used world-wide for high-speed applications such as for statistics and pre-selection for weight enforcement and tolling. This installation shows that Lineas® sen-sors can also be used successfully for high-accuracy weighing under low speed conditions.

About the Kistler Group
The Swiss-based Kistler Group is a leading global supplier of dynamic measurement technology for pressure, force, torque and acceleration. Kistler’s technology is used to analyze physical processes, control industrial processes and optimize product quality.

Kistler has a full range of sensors, electronics and systems for engine development, vehicle technolo-gy, assembly technology, plastic and metal processing as well as for biomechanics.

The Group maintains its global presence through 28 sales and manufacturing companies, with tech centers on all continents and more than 30 agencies. This enables the Group to keep in direct contact with its customers and offer individualized application support.

The Kistler Group employs a workforce of 1,200 people and generated revenues of CHF 279 million in 2012.