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September 21, 2020
How to calibrate scales of concrete batching plant
Generally speaking, the measurement accuracy of concrete batching plant is very high, but in actual use, its accuracy may be affected due to equipment removal, disassembly and assembly, etc. At this time, it is necessary to calibrate the scale. But how to calibrate the batching plant?
1. Static measurement verification
When these situations occur in the concrete mixing plant, static measurement verification is required, and records should be made: no less than once a quarter under normal production conditions; production is stopped for more than 1 month (including 1 month), before re-production; production is generous Before concrete; when abnormal conditions occur.
The loading value of the static measurement verification should be consistent with the actual production situation. The loading should be carried out in grades, and the number of grades should not be less than 5. When the static verification result exceeds the verification error range of the statutory metrology department, the cause must be found and the statutory metrology department re-verify.
2. Regular calibration of weighing scales
According to the relevant national regulations, the weighing scale needs to be calibrated regularly; when the external equipment or use conditions of the mixing station change, the electronic weighing scale must be calibrated before using the electronic weighing scale.
①Check whether the wiring of the load cell, intermediate junction box, CB80 line, signal transmitter, and AD module is correct.
②Check whether the ground terminal of the CPU power module, the inner shielding layer of the CB80 line, the PE ground terminal of the signal transmitter, and the negative of all AV lines are firmly grounded.
③Check whether there are sundries and welding and connecting objects on the scale. After power on, check whether the working power of the signal transmitter is 24V, the working voltage of the sensor (black, blue and green, yellow) V+/- is 12V, the sensor Whether the signal voltage (white and red) SI+/- is between 0-20mV.
④Adjust the DIP switch of the signal transmitter, adjust the multiple of signal amplification through the combination of different DIP codes, and then adjust the output voltage of the signal transmitter AV+/- (the range of the AV voltage value is 0 through the zero adjustment potentiometer) -10 V) to 0.5V-1.0V.
⑤ After entering the calibration interface, initialize and reset each scale one by one, and perform preliminary calibration of the weighing range of each scale (only need to use dozens of kilograms of weights or objects with equivalent weight when calibrating the scale), after calibration If the weighing range is too small, you need to reduce the transmission magnification; if the weighing range is too large, you need to increase the transmission magnification; repeat steps 3 and 4.
⑥In the process of weighing the scale during preliminary calibration, it can be judged whether the transmitter is in good condition by measuring whether the input (SI+/-) and output (SO+/-) voltages of the signal transmitter increase in proportion.
⑦If the weight value of the scale fluctuates up and down, check whether the grounding is reliable; if the input voltage of the transmitter is normal but the output voltage of the transmitter is abnormal during the calibration or use, it can be judged that the transmitter is faulty. Replace it. Sender for processing.