Electronic Truck Scale is main consist of loadcell,structure component and indicator.The accuracy grade is class III from 1/1500 to 1/10000.
The A/D transfer circuit can meet the precision because of its strong anti-interference capability and low cost etc advantage.
Reduce the error ways in the process of design and production.
1.Loadcell tachnical guarantee
Select the loadcell that meet all technical requirement is the key of ensure the truck scale quality.Linearity, creep, temperature coefficient and sensitivity temperature coefficient are important requirement of sensor. For each batch of sensors, the sampling inspection and high – temperature testing must be conducted according to the sampling rate required by the relevant national standards.
2.Truck Scale circuit temperature coefficient
Theoretical analysis and experimental results show that input resistor and feedback resistor temperature coefficient is the important factor of affecting the temperature coefficient of truck scale sensitivity. It is necessary to select the temperature coefficient of 5 × 10-6 metal film resistor.It must be tested in certain high temperature for each scale. For some ultra-poor products can be compensated by temperature coefficient of less than 25 × 10-6 metal film resistor. The temperature aging had been done at the same time in the process of high temperature testing. It improves product stability.
3.Electronic scale nonlinear compensation
In the ideal case, it is linear relationship between the digital conversion of the digital and the weight imposed on scale. It is via the internal computer program for single point calibration in the process of production. It is stored in the memory according to the ideal line to calculate the slope of the number and weight. It can not overcome the non-linearity of the sensor and the integrator. With multi-point correction and using multiple lines to approximate a curve effectively reduces the non-linearity error and not increase the hardware cost. For example, 1/3000 accuracy of the electronic truck scale is calibrated with 3-point correction, 1/5000 accuracy of truck scale is with 5-point calibration.
