1 Electrical experiment and wiring

(1) The load cell must be subjected to on-site acceptance test before installation: the appearance and ex-factory data inspection should be consistent with the ordering requirements; the insulation resistance measurement, DC resistance test, output sensitivity test, and test results are performed according to the “load sensor test method”. Compared with the factory test record or the original value, if there is obvious abnormality, it reflects the problem and must be processed to meet the requirements before installation.

(2) Strictly prevent the input and output terminals from being staggered, causing the output value to change and the measurement cannot be performed. The method of confirming the input and output of the sensor is to measure the DC resistance value with a multimeter. The input and output resistance values should be basically equal, but when there is accurate compensation, the input resistance will be slightly larger than the output resistance.

(3) The signal cable of the sensor can not be arranged in parallel with the strong power supply line or control line in the same channel to avoid introducing interference. If they must be placed in parallel, the distance between them should be kept above 50cm, and the signal wires should be covered with metal tubes.

(4) The sensor output polarity should correspond to the meter indication. When the load increases, the weighing indicator increases; otherwise, the opposite. Otherwise, the two-wire end of the sensor input (or output) should be reversed.

2 Mechanical installation process

(1) When the sensor is installed, it is necessary to ensure that the load is applied by the loading point along the sensor loading axis, and it is necessary to avoid the force splitting and mechanical interference factors. In combination with multiple sensors, in order to prevent eccentricity errors, the arrangement should be such that each sensor is equally stressed, for example, three sensors should be evenly arranged at 120°. At the same time, the tie rod should be vertical, and the deviation of the verticality including the temperature difference expansion should not exceed 3°.

(2) The sensor suspension device should have sufficient rigidity to avoid unloading zero return and weighing error. In use, it is not advisable to use a cushion rubber pad between the scales and the boom.

(3) When the installation and commissioning, the tare weight measurement is verified by the standard weight. The accuracy of the system should meet the requirements, that is, the accuracy of the commercial concrete weighing system is better than 0.5% FS; the measurement of the combined sensor load consistency should meet the manufacturer's design requirements. That is, the difference between the rated output sensitivities of the sensors is not more than 1.5%; the voltage of the sensor bridge is completely the same; the eccentricity of the tare structure causes the eccentric load to not exceed 10%.

(4) After the sensor is combined with the loading mechanism, avoid welding work to avoid burning the sensor. However, when welding is required, install a multi-core soft copper wire for short circuit between the upper and lower booms of the sensor.

(5) In the use of the sensor, strong heat radiation must be avoided, especially strong heat radiation on one side. Although the sensor uses temperature compensation, it is often difficult to play its due role because it is not at a uniform temperature. If necessary, add asbestos or fiberglass to insulate it.