On the basis of analyzing the existing problems, application experience and market requirements of the integrated digital intelligent load cell, the US STS company launched the separated 2200 series digital load cell module in 1992. It is to move the A/D conversion digital processing circuit originally placed inside the load cell to an external junction box. A junction box with A/D conversion module is called a digital junction box. After connecting the ordinary analog load cell to the digital junction box, its output is transmitted to the weighing display control instrument with digital signal. Generally, the mode of analog load cell plus digital junction box is called modular digital load cell system. It not only retains the comprehensive performance indicators of the analog load cell, but also has all the features and functions of the overall digital intelligent load cell. At the same time, the working environment of A/D conversion circuit is improved to the maximum extent. The characteristics of the modular digital load cell system are:
(1) Under the condition of no change in the analog load cell, the analog signal output is changed to the digital signal output through the digital junction box (the correct use method of the weight junction box), so that it has the characteristics and function of the overall digital intelligent load cell;
(2) The modular digital weighing sensor system can realize the digitalization of the electronic weighing device without changing the original electronic weighing device structure;
(3) The analog weighing sensor can work normally under an environmental condition of 4070℃, and the digital junction box can make the modular digital weighing sensor system work in a wide temperature range;
(4) Compared with the overall type, the stability and reliability of the separated modular digital load cell system have been greatly improved:
(5) The installation and wiring is very simple, there is only one cable from the digital junction box to the digital weighing instrument;
(6) Because it is equipped with ordinary analog weighing sensors, it is easy to maintain and repair, and the maintenance cost is lower than the overall type.
