Language
Author: Smartweigh–Multihead Weighter
The digital display multihead weigher designed in this paper is a weighing control display device based on the resistance strain force sensor and the design of the single chip microcomputer as the key to control. The detection range is 0-10kg, and the measurement accuracy is±2g, the liquid crystal display screen displays the information of the precise measurement data, in addition, the information of the precise measurement data can be sent to the electronic computer for display information according to the serial port. The system software has the characteristics of high precision, stable characteristics and simple operation. The frame diagram of the multihead weigher design scheme is shown in Figure 1 below: 1. The hardware configuration circuit principle 1.1. The weighing sensor resistor The strain force weighing sensor is composed of many key parts such as resistance strain gauges, polyurethane elastomers and inspection power supply circuits. constitute.
The polyurethane elastomer causes elastic deformation under external force, so that the resistance strain gauge attached to its surface also causes deformation. After the resistance strain gauge is deformed, its resistance value will change (expand or decrease), and then through relatively accurate measurement The power circuit converts this resistor into an electronic signal (working voltage or current), and then completes the whole process of converting the external force into an electronic signal. Check the power supply circuit as shown in Figure 2, and change the resistance of the resistance strain gauge into a working voltage output. Because the Wheatstone bridge has many advantages, such as the ability to suppress the harm of temperature change, to suppress the influence of side force, and to easily deal with the compensation problem of the weighing sensor, the Wheatstone bridge has gained a great advantage in the weighing sensor. universal use.
The weighing sensor generally has a total of four output lines, and the output resistance is generally 350Ω, 480Ω, 700Ω, 1000Ω. The input end generally carries out some compensation for temperature and sensitivity, and the input end resistor will be higher than the output end. 20 ~ 100Ω, so Use a digital multimeter to measure the resistance value to identify the output terminals. 1.2. The output data signal of the amplifying circuit strain-type weighing sensor is not strong (mV or even μV heavyweight), and there is often a lot of noise along with it. For such a data signal, the first step in the power supply circuit solution is generally to select an instrumentation amplifier to first enlarge the small data signal.
The instrumentation amplifier power supply circuit has stronger common mode rejection capability than the simple differential signal amplifier circuit. The most critical purpose of increasing is not the gain value, but only to improve the frequency stability of the power supply circuit. In this design scheme, the instrumentation amplifier adopts the structure of OP07 three operational amplifiers.
3 as shown in Fig. When R1=R2, R3=R4, Rf=R5, the gain value of the power supply circuit is: G=(1+2R1/RG1) (Rf/R3). It can be seen from the formula calculation that the adjustment of the gain value of the power supply circuit can be completed by changing the resistance value of RG1.
1. 3. A/D conversion power supply circuit A/D converter selects electronic scale-specific integrated icHX711, which is a 24-bit A/D converter integrated ic specially designed for high-precision electronic scales. Compared with other integrated ICs of the same type, the integrated IC integrates the peripheral circuits necessary for other integrated ICs of the same type, including an adjustable regulated power supply, an on-chip clock oscillator, and the like. Enter the switch to choose the safety channel A or the safety channel B at will, and the internal low-noise program controller amplifier is connected between the two.
The gain value of the program controller of the safety channel A is 128 or 64, and the corresponding full credit limit differential signal input data signal amplitude value is respectively±20m.
Author: Smartweigh–Multihead Weighter Manufacturers
Author: Smartweigh–Linear Weighter
Author: Smartweigh–Linear Weigher Packing Machine
Author: Smartweigh–Multihead Weighter Packing Machine
Author: Smartweigh–Tray Denester
Author: Smartweigh–Clamshell Packing Machine
Author: Smartweigh–Combination Weighter
Author: Smartweigh–Doypack Packing Machine
Author: Smartweigh–Premade Bag Packing Machine
Author: Smartweigh–Rotary Packing Machine
Author: Smartweigh–Vertical Packaging Machine
Author: Smartweigh–VFFS Packing Machine
Copyright © Guangdong Smartweigh Packaging Machinery Co., Ltd. | All Rights Reserved
