Strict weighing sensor installation process

1 Electrical experiment and wiring

(1) The load cell must be subjected to an on-site acceptance test before installation: the appearance and factory data inspection must be consistent with the order requirements; according to the "load sensor test method" to carry out insulation resistance measurement, DC resistance test, output sensitivity test, and test results Compared with the factory test record or the original value, if there is an obvious abnormality, it reflects the existence of the problem, it must be dealt with, and the installation can be carried out after reaching the requirements.

(2) Strictly prevent the interleaved connection of the input and output terminals, which may cause the output value to jump and make measurement impossible. The method to confirm 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 ^ compensation, the input resistance will be slightly larger than the output resistance.

(3) Generally, the signal cable of the sensor cannot be arranged in parallel with the strong current power 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 line should be covered with a metal tube.

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

2 Mechanical installation process

(1) When the sensor is installed, to ensure that the load acts from the loading point along the loading axis of the sensor, it is necessary to avoid force shunting and mechanical interference factors. In the combined use of multiple sensors, in order to prevent eccentric load error, the arrangement should make the force of each sensor consistent. For example, 3 sensors should be evenly arranged at 120°. At the same time, the tie rods should be vertical, and the vertical deviation including temperature difference expansion should not be greater than 3°.

(2) The sensor suspension device must have sufficient rigidity to avoid unloading non-return to zero and weighing errors. In use, pay attention to the buffer rubber pad between the bucket and the boom.

(3) The tare weight measurement is verified with standard weights during installation and debugging, and the system accuracy must meet the requirements, that is, the accuracy of the commercial concrete weighing system is better than 0.5% FS; the measurement of the load consistency of the combined sensor should meet the manufacturer's design requirements, That is, the difference between the rated output sensitivity of the sensor is not more than 1.5%; the bridge voltage of the sensor is exactly the same; the eccentric load caused by the eccentric tare structure is not more than 10%.

(4) After the sensor is assembled in the loading mechanism, avoid electric welding to avoid burning the sensor, but when electric welding is required, a short-circuit multi-core soft copper wire should be installed between the upper and lower booms of the sensor.

(5) During the use of the sensor, strong thermal radiation must be avoided, especially one-sided strong thermal radiation. Although the sensor uses temperature compensation, it is often difficult to play its due role because it is not at a uniform temperature. When necessary, asbestos or glass fiber should be added for heat insulation.