The basic composition of electronic belt scale mainly includes: belt conveyor and its drive unit (although the manufacturer of embedded belt scale is generally not provided, but without it belt scale is incomplete, it can not work properly.) Weighing unit, speed unit, signal acquisition, processing and control unit.

For the conveyor belt scale, the whole belt conveyor is the carrier; For weighing table belt scale, its weighing platform and weighing roller and just above the running of the conveyor belt constitute a load carrier.

I

1.single lever type weighing frame

There is only one set of weighing lever, on which a set or several sets of weighing rollers are supported. The balance frame is usually composed of weighing lever, fulcrum, balance weight, etc., with simple structure, but the weighing accuracy is not high, the precision is usually 1% ~ 2%.

2. double lever balance frame

Consists of two groups of weighing lever, symmetrical, each weighing lever support a group or several groups of weighing roller, scale frame structure is complex, large scale body, but the two groups of weighing lever in the weighing process can offset some of the horizontal component of the (such as belt tension, the belt running deviation caused by the lateral force) on the weighing accuracy, the influence of the weighing accuracy is higher, so I stable performance, precision generally is 0.25% ~ 0.5%.

3. Cantilever scale frame

Usually is used in the special short belt conveyor, the whole of the short belt conveyor only by the fulcrum and weighing sensor bearing, this scale is only used for the size of short quantitative feeder or special metering belt scale, weighing accuracy is medium, the accuracy is usually around 1%.

4. Suspension scale frame

The suspended weighing platform is similar to the static weighing platform, on which one or more sets of weighing idlers are supported.

Weighing instrument

Weighing instrument from the early analog instrument, developed to the present microcomputer instrument. Instrument accuracy from 0.1 %, 0.05 % to 0.01 %. Microcomputer instrument has the form of single chip microcomputer, PLC, industrial PC, embedded PC and so on. Microprocessor-based weighing instrument adopts low drift high gain amplifier, high resolution A/ D converter, flash memory, electric erasable memory and non-volatile random access memory, rs-232 / rs-485 communication standard, field bus and other technologies, which greatly improve its performance and function. At the same time, also applied the Σ Δ modulating AD converter and new technologies, such as the surface of the printed circuit board installation. The adoption of these new technologies has further improved the performance and reliability of the weighing instrument and created favorable conditions for the miniaturization of the instrument. Performance has been achieved: nonlinear better than 0.01 %, sensitivity better than 0.2 V/ d,A/ d conversion speed is generally 10 ~ 30 times/s, for dynamic weighing can reach more than 100 times/s.

The functions include setting various parameters, such as dividing value, measuring range, calibration parameters, calculation coefficient, tare weight, etc. Zero point automatic tracking; Automatic peeling; Automatic range calibration; Dynamic detection; Startup self-test and fault diagnosis; Power failure data protection; Overload alarm; Nonlinear compensation; And the display of gross weight, net weight, tare weight and accumulated value, etc. In order to facilitate communication with the computer, current weighing instruments are equipped with input/output interfaces, such as rs-232c, rs-485, 20 mA current loop, analog (4 ~ 20 mA) and relay outputs.