How to deal with the excessive zero output of the truck scale

1: Detect whether the input and output impedance of a single floor scale is within the range

There are roughly four-wire and six-wire junction boxes in the column and bridge-type platform scales. The six-wire system has an extra set of feedback lines, which can reduce resistance, maintain constant voltage, and avoid signals caused by line length Failure, so it is better than the four-wire system. The output impedance of these two ground scale junction boxes is generally between (350±1)Ω; the input impedance is between (382±4)Ω.

2: When judging whether the output of the ground scale zero point is too large, you can measure the voltage signal on the total signal cable in the empty scale state.

3: The meter value fluctuates violently, and sometimes it is necessary to measure the insulation resistance between the shielded wire and other wires (theoretical value is greater than or equal to 5000M). You can use a multimeter to measure the insulation resistance between the shielded wire and any other wire with the highest level (such as 20MΩ), and the display should be infinite (be careful not to touch the meter stick)

Drift processing of truck scale, floor scale, and electronic floor scale sensor:

There are many reasons for the drift of the weighbridge sensor zero point. For example, for the pressure loadometer sensor, the component parameters in the bridge circuit are not symmetrical; the temperature coefficient of the sensitive grid material of the elastic element and the resistance strain gauge, the linear expansion coefficient are different, and the bridge lead length is inconsistent. Comprehensive factors such as the last result in the loadometer sensor After forming the electric bridge, the overall temperature coefficient of adjacent arms has a certain difference. When the temperature changes, the resistance of the adjacent arms changes differently, which causes the output of the bridge to be unbalanced, that is, zero drift; for smart weighbridge sensors, time drift— -For the system, as time increases, it is equivalent to aging the system. In this way, the structural characteristics of the system will change and drift will occur.