The connection of the weighing module determines the accuracy and stability of the weighing result. The Wheatstone bridge of the weighing sensor is formed by sticking the resistance strain gauge on the elastic body. When the elastic sensitive element does not bear the load, the resistance of the strain gauge remains unchanged, the bridge is balanced and the output voltage is zero. On the contrary, the resistance of the strain gauge changes, the bridge loses balance, and the weighing sensor outputs a voltage signal proportional to the weight of the measured load.
020-34563445Weighing module usually takes strain gauge as sensitive element, and adopts A189C51 single chip microcomputer. 89C51 is a product compatible with MCS-51 chip, and the chip has 8K fast erasable program memory (erasable times can reach 1000 times), with fast operation speed and frequency up to 24 MHz. 32 is an I/O port bus and three 16-bit timekeepers/counters. Digital weighing module is composed of filter control system and A/D converter, in order to reduce the burden of single chip microcomputer.
Hardware filtering is adopted, and its filtering cut-off frequency can be controlled by single chip microcomputer. MAX293 is a very convenient 8-order low-pass elliptic switched capacitor filter. MAX293' s transition ratio of 1.5 provides a sharp inclined edge and a stopband attenuation of 80dB. The steep inclined edge and high-order characteristics make this filter very suitable for sound signal filtering. 12-bit A/D converter with track/hold multiplexer. MAX180 is a complete 12-bit acquisition (DAS), which includes an 8/6-channel input multiplexer, a wide-band tracking/keeping low drift, a reference voltage source and a widely used controller interface. It has the characteristics of high conversion speed, easy interface with industrial computer and low power consumption.
The metering module is also a detection device, which can sense the measured information, and can transform the sensed information into electrical signals or other required forms of information to meet the requirements of information transmission, processing, storage, display, recording and control, and is usually composed of sensitive elements and conversion elements. Among them, the sensitive element refers to the item that can be directly sensed in the weighing sensor, and the conversion part refers to the part of the weighing sensor that can convert the output of the sensitive element into an electrical signal suitable for transmission and measurement.
technical parameter
* rated load (r.c.): 5t, 10t, 20t, 30t, 50t, 60t, 100t, 150t, 200t.
* rated output (r.o.): 2 0.005 mv/v.
* Zero point balance: 0.030mv/v.
* Comprehensive error: ±0.03%R.O 。
* nonlinearity: ±0.03%R.O
* Lag: ±0.03%R.O 。
* Repeatability ±0.02%R.O 。
* Creep (30min): ±0.03%R.O 。
* Normal operating temperature range: -10...+40℃
* allowable working temperature range: -20...+70℃
* Influence of temperature on sensitivity: 0.02% r.o./10℃
* Influence of temperature on zero point: 0.02% r.o./10℃
* Recommended excitation voltage: 10V(DC/AC)
* Maximum excitation voltage: 15V(DC/AC)
* Input impedance: 385 10 Ω
* Output impedance: 350 3 Ω
* insulation impedance: > 5000MΩ
* safety overload: 150%R.C
* ultimate overload: 300%R.C
* Elastic element material: alloy steel
* Protection grade: IP67
* Cable length: 4m(0.25t…2t),6m(3t…10t)
