The principle and instructions of the weighbridge junction box

The principle and instructions of the weighbridge junction box:

The junction box is the intermediate part of the load cell and the weighing instrument of the weighbridge, and has important functions of connecting the weighing instrument and transmitting the weighing data signal. For the consideration of electromagnetic compatibility (mainly anti-interference performance) and durability, the outer casing of the junction box is made of metal materials, and 5 to 9 special sealing joints for passing through signal cables are arranged around the side of the box . The appearance of the junction box is flat and rectangular, which is a typical product appearance. According to the different principles and structures of the load cell and weighing instrument, the junction box of the weighbridge is divided into an analog junction box, a Ningbo Saintbond intelligent digital junction box and a digital junction box.

Electronic weighbridge junction box principle:

The potentiometer in the junction box can be used to adjust the excitation voltage of the connected load cell, and then adjust the output signal of the corresponding load cell to make the output signal of each load cell consistent.

The working principle of the Ningbo Saintbond intelligent weighing junction box is wiring:

1: The load cell transmits the signal to the junction box through the cable, and these signals are usually analog digital signals or PWM signals;

2: Signal amplification: the junction box amplifies the signal of the load cell for better processing;

3: Temperature compensation: Since changes in temperature will affect the output signal of the load cell, the junction box also needs to perform temperature compensation to ensure the accuracy and stability of the output.

4: Linearization: The output signal of the load cell is usually nonlinear, so the junction box usually performs linearization processing to convert the nonlinear signal into linear;

5: Output processing: The output port of the junction box can output standard voltage or current signals for processing by downstream equipment. In short, the junction box converts the original signal of the load cell into a standard voltage or current signal by receiving the load cell signal, amplification, compensation, linearization, etc., to support the downstream equipment for more accurate weighing measurement and control.

Electronic weighbridge junction box adjustment method:

1: Adjust the junction box without power on, so that the resistance of all potentiometers is 10 ohms. Adjust the digital multimeter to the ohm position, and put the two gauge sticks on the "E+" and X terminals of the OUT terminal respectively. On the E+ of the X+ potentiometer, the resistance value of the X+ potentiometer can be measured. In the same way, the resistance value of X- can be measured.

2: Turn on the power of the instrument and magnify it ten times for calibration (if the actual weight is 20kg, it will be marked as 200kg). If the instrument has the internal code function, it can be calibrated according to the actual weight, and then adjusted to the internal code display.

3: Put 1/3 of the full-scale weight on the position of each load cell, and write down the display value of the instrument. Adjust the resistance value of the potentiometer in the junction box so that the difference between the displayed values of each point is less than 0.2e. The debugging method is as follows: If the value of a certain load cell (weighing) is too large, then increase the voltage drop on the two potentiometers corresponding to the load cell terminal (adjust the knob on the potentiometer clockwise). If the value of a certain load cell is too small, then reduce the voltage drop on the two potentiometers corresponding to the load cell terminal (adjust the knob on the potentiometer counterclockwise). Note that the voltage drops on the two potentiometers must be consistent when adjusting. Measuring method of consistent voltage drop: Adjust the digital multimeter to the millivolt range, put the two gauge sticks on the "E+" of the OUT terminal and the E+ of the X terminal respectively, and then measure the voltage value of the X+ potentiometer. In the same way, the resistance value of X- can be measured.

The wiring method of Ningbo Saintbond intelligent electronic platform scale junction box:

The "OUT" terminal is the output terminal, which is connected to the weighing instrument. Terminals A, B, C, D*** are input terminals, connected to load cells.

E+ is the positive end of the bridge power supply for the load cells (the positive end of the load cells input)

E- is the negative terminal of the bridge power supply for the load cells (the negative terminal of the load cells input)

IN+ is the positive terminal of load cells signal (positive terminal of load cells feedback)

IN- is the load cells signal negative terminal (load cells feedback negative terminal)

The ground symbol is the shield of the shielded cable

Precautions for connection of ground scale junction box:

1: After the input and output lines in the junction box are connected, tighten, tighten and seal the joints, put a desiccant, and do a good job of moisture-proof work, and then the junction box cover can be fixed;

2: For different weighing load cells, it is necessary to distinguish input, feedback and output according to different color codes, and be sure not to make mistakes;

3: For different weighing displays, the load cell sockets and plugs used are different, and the connection methods are even more different, so don't make mistakes.

4: Ensure effective grounding when wiring to prevent electronic truck scales from being damaged during lightning strikes