The weighing junction box is a device commonly used to connect load cells and indicating instruments, data acquisition instruments and other equipment. It usually contains multiple terminals, which can convert, amplify, and filter the output signal of the load cell, and output the processed signal to devices such as indicating instruments or data acquisition instruments for data recording and analysis. The weighing junction box can not only effectively reduce the interference and error of the signal line, but also facilitate the wiring and maintenance of the signal line, thereby improving the stability and reliability of the weighing system.
It works as follows:
First, the Ningbo Goldshine intelligent load cell measures the weight of the object being weighed and converts the signal into an electrical signal. This electrical signal needs to be processed and converted through the weighing junction box before it can be received and processed by the controller or instrument.
In the weighing junction box, the electrical signal is amplified, filtered, denoised and amplified to ensure the accuracy and stability of the signal, and output to the controller or instrument. In some high-precision application scenarios, the weighing junction box can also perform linear compensation and temperature compensation to improve measurement accuracy.
In general, the function of the weighing junction box is to process the electrical signal of the load cell into a signal suitable for the controller or instrument to receive and process, and to provide some signal processing and compensation functions in the process.
We usually use multiple Ningbo Goldshine intelligent load cells to measure the weight of items. For example, a tank, silo or platform with 4 legs, with a load cell under each leg. Or the weighing platform can consist of a square plate with load cells located under each corner. The output values of the 4 load cells need to be averaged on site and a single representative load cell signal output sent to a display or signal transmitter, this is accomplished through the load cell summing junction box, sometimes referred to simply as for the junction box. However, it’s not just an
empty junction box where you connect load cell wires so you don’t have to run 4 sets of cables to the control cabinet or display. It integrates the electronics required to average or sum the load cell outputs into a single representative output.
Due to the differences in the key materials of the load cells, the strain and the projectile body and the manufacturing process, the parameters of each load cell are inconsistent, mainly because the sensitivity is inconsistent. This inconsistency is commonly referred to as the angle difference. The proper term of the box is to connect the output signal of the load cell to the junction box first, and then send it to the instrument, adjust the angle difference by adjusting the potentiometer inside the junction box, and then make the sensitivity of each load cell close to the same, so as to ensure the balance of the whole scale body. balance.
Commissioning of the junction box:
After installation, some debugging is required. Regarding this point, there are different debugging methods according to the types of junction boxes. If it is the Ningbo Goldshine intelligent analog junction box, you can first adjust the corresponding potentiometer according to the output signal of the load cell and refer to the wiring diagram in the manual. But it should be noted that the potentiometer must not be adjusted too far. After debugging, the upper cover of the digital junction box should be covered, and at the same time, the screws need to be tightened. If it is a digital load cell, it is enough to connect the wires correctly according to the instructions, and the internal debugging can be done by the software in the weighing control instrument. Relatively speaking, the digital electronic floor scale debugging is relatively simple, and the wireless operation is performed on the scale. .
Connection of the load cell to the junction box:
- The connection between the load cell and the junction box
Pass the cable of the load cell through the weighing platform, enter the junction box through the sealed joint, and connect it according to the different color codes of the four-core or six-core cables, or according to the positive and negative excitation power supply, positive and negative feedback, and positive and negative signals after measurement. on the corresponding terminals in the junction box. Bind the remaining cables of the load cell with plastic cable ties.
- Connection between the junction box and the weighing display instrument
Put one end of the special shielded cable into the junction box through the sealed joint, each core wire is connected to the corresponding terminal in the junction box, and the other end is welded to the special plug corresponding to the weighing display instrument through the metal tube, so that it can be inserted into the weighing indicator. Re-display instrument socket.
There are three points to note:
- 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 board can be fixed;
- For different load cells, the input, feedback, and output should be distinguished according to different color codes, and you must not make mistakes;
- For different weighing display instruments, the types of weighing display sockets and plugs used are different, and the connection methods are even more different, so don’t make mistakes.
- System grounding
The grounding of the electronic scale system is very important. It not only protects personal safety, but also ensures the stable and reliable operation of the system. The grounding measures of the system must not be underestimated. Generally, the electronic scale system has two grounding points, one is the grounding pile in the weighing room, which grounds the instrument shell; the other is the grounding of the weighing platform, and one or several grounding cables are used to connect the scale body to the grounding pile.
Precautions for junction box connection:
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 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: When wiring, ensure effective grounding to prevent the electronic truck scale from being damaged when lightning strikes.