Electronic floor scales (truck scales) generally use bridge QS load cells. Generally, 4-8 load cells are collected in the junction box, and then connected to the instrument by a main line. load cells of different manufacturers should be connected according to the instructions. The load cell wires made by different manufacturers are different in color. The four wires are positive and negative excitation and positive and negative signals. Generally, the color of the load cell line is divided into red and black, green and white. Red, black, green and white: the red, white, green and blue sub-marks indicate that V+, V-, S+, and S- are connected to the junction box in turn. According to the structure and distribution of the weighing platform, connect to the junction box 1, 2, 3, 4, 5, 6, 7, 8 and label. This is convenient for maintenance.
There are two ways to wire out the load cell: 4-wire and 6-wire. There are also 4-wire and 6-wire wiring for the module or weighing transmitter. Whether to connect 4-wire or 6-wire depends on your hardware requirements. , The principle is: the load cell can be connected to 6 wires but not to 4 wires, and the load cells that must be connected to 4 wires must be short-circuited.
General load cells are all six-wire systems. When connected to a four-wire system, the power lines (EXC-, EXC+) and feedback lines (SEN-, SEN+) are respectively short-circuited. SEN+ and SEN- are used for compensating circuit resistance. SEN+ and EXC+ are connected, and SEN- and EXC- are connected.
EXC+ and EXC- supply power to the load cell, but due to the line loss between the weigh module and the load cell, the voltage received by the load cell will actually be less than the supply voltage. Each load cell has a characteristic of mV/V. The mV signal it outputs is closely related to the received voltage. SENS+ and SENS- are actually a high-impedance loop in the load cell. The received voltage is fed back to the weighing module. Assuming EXC+ and EXC- are 10V, the line loss, the load cell is 2mV/V, in fact the maximum signal output by the load cell is ()*2=19mV instead of 20mV. At this time, the load cell will use 19mV as the maximum range, provided that the load cell must feed back the actual voltage to the weighing module through a feedback loop. Short-circuit EXC+ and SENS+, and short-circuit EXC- and SENS- on the load cell. This is limited to occasions where the distance between the load cell and the weighing module is relatively small and the voltage loss is very small, otherwise there will be errors in the measurement.
How to wire the weighbridge junction box and the load cell
General load cells are all six-wire systems. When connected to a four-wire system, the power lines (EXC-, EXC+) and feedback lines (SEN-, SEN+) are respectively short-circuited. SEN+ and SEN- are used for compensating circuit resistance. SEN+ and EXC+ are connected, and SEN- and EXC- are connected.
The ground scale debugging is controlled by a junction box. There are more junction boxes for the wire and circuit as a transition. After the wire and the junction box stop connecting, it will also have a certain maintenance effect on the circuit. In special needs, waterproof junction boxes and explosion-proof junction boxes came into being.
The junction box is the heart of the weighbridge, and it cooperates with the load cell to stop the integration of the weighing data from the load cell and display it through the weighing instrument.
How to wire the weighbridge junction box and the load cell? Electronic weighbridges are common in shopping malls. The weighbridge is composed of a weighing platform and a weighing display controller, as well as high-precision electronic weighing load cells and infrastructure. The latest weighbridges will also be equipped The large field screen can display weighing data in real time, and there is a monitoring system that provides digital monitoring and an unattended long-distance monitoring system.
For a floor scale, some people think that the important thing is a scale and a load cell, but the junction box is not important. In fact, this idea is wrong. Whether the junction box of the electronic platform is good or not will determine whether the weighing system is normal. Although the inductor is important, the junction box is just as important.
