CN203798443U - Composite sensor signal special-purpose digital processing system - Google Patents

Abstract

The utility model discloses a composite sensor signal special-purpose digital processing system comprising a 64-path weighting sensor, an amplification filtering module, an A/D conversion module, and a decoder and a circuit connected with the decoder; the weighting sensor, the amplification filtering module, the A/D conversion module, a buffer and a secondary filtering amplification module are connected in sequence, and are connected with an industrial control computer through a PCL data bus. One end of the decoder is connected with the PCL data bus, and the other end of the decoder is connected with an electric level trigger through a chip selection device; the electric level trigger is connected on the A/D conversion module. The composite sensor signal special-purpose digital processing system employs a novel composite configuration, 64-path signal single digital processing capacity is provided, consistent property of all sensors of the system can be maintained, thereby effectively reducing signal errors generated by machinery problems of the composite sensor, realizing stability of sensor outputting signals, and realizing high speed and high accuracy acquisition of the weighting data.

Description

A kind of compound sensor signal special digital disposal system

Technical field

The utility model relates to a kind of digital processing system system, relates in particular to a kind of compound sensor signal special digital disposal system.

Background technology

Also do not have in the market compound sensor 64 road special digital disposal systems, existing disposal system is thrown away and is adopted traditional version, and the form with 8 circuit-switched data signals after sensor signal parallel connection is directly transferred to data acquisition module.Data acquisition module adopts based on isa bus mode, and cpu resource takies too high, and data transfer bandwidth is too little, takies hardware interrupts resource etc.And because site environment disturbing factor is numerous, the data fluctuations that collects is large, poor stability, weighing precision are low.The state of weighing that cannot comprehensive each sensor of dynamic monitoring, thus can not keep the consistance of each sensor, cannot in vehicle operating, realize weighing data at a high speed, sampling with high precision.

Utility model content

For the weak point in addressing the above problem, the utility model provides a kind of compound sensor signal special digital disposal system.

For solving above technical matters, the technical solution adopted in the utility model is: a kind of compound sensor signal special digital disposal system, and it is by LOAD CELLS, amplification filtering module, A/D modular converter, code translator and the electric circuit constitute that is connected thereof; LOAD CELLS Wei64 road; LOAD CELLS, amplification filtering module, A/D modular converter, impact damper, secondary filter amplification module are connected successively, and are connected with industrial computer by PCL data bus.

Code translator one end is connected with PCL data bus, and the other end selects device to be connected with level trigger by sheet; Level trigger is connected on A/D modular converter.

The utility model adopts new composition configuration, there is the independent digital processing ability of 64 road signal, the consistance of keeping system all the sensors, effectively reduced the signal errors that the mechanical problem because of compound transducer produces, realized the stability of sensor output signal, improved dynamic weighing data accuracy, digital processing system is based on PCL bus mode, transmission speed is faster, and the state of weighing of each sensor is carried out to comprehensive dynamic monitoring, realized weighing data high speed, sampling with high precision.

Accompanying drawing explanation

Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.

Fig. 1 is existing system unitized construction schematic diagram.

Fig. 2 is unitized construction schematic diagram of the present utility model.

Fig. 3 is foundation structure schematic diagram of the present utility model.

Fig. 4 is PCL data line signal input schematic flow sheet.

Fig. 5 is filtering and amplifying circuit structural representation.

Fig. 6 is the output flow path switch of CS while being low level

Embodiment

As shown in Figure 2, the main You64 of the utility model road LOAD CELLS 1, amplification filtering module 2, A/D modular converter 3, code translator 4 and the electric circuit constitute that is connected thereof.LOAD CELLS 1, amplification filtering module 2, A/D modular converter 3, impact damper 5, secondary filter amplification module 6 are connected successively, and are connected with industrial computer by PCL data bus.

Code translator one end is connected with PCL data bus, and the other end selects device to be connected with level trigger by sheet; Level trigger is connected on A/D modular converter.

1, the transmission of signal

In weighing system, the core measuring sensor of foundation weighing device is the compound sensor that multichannel LOAD CELLS is combined into, form by compound transducer simulating signal with 64 circuit-switched data signal outputs, is transferred to compound sensor signal special digital disposal system.Foundation structure is as Fig. 3.

2, decoded signal is selected circuit

Because data handling system is the data acquisition based on PCL bus mode, at the equipment of industrial computer internal operations, there is independently address.Digital processing system is as the equipment of new interpolation, and also needing has fixing address.

It is by code translator and control circuit that decoded signal is selected the Main Function of circuit, controls 64 road A/D conversions, by sheet, selects device and code translator to realize the selection of code translator signal.In PCL, address wire is exported after different address signals, and sheet selects the device Enable Pin of trigger decoder exactly.Sheet selects device to select 74LS30 chip, 74LS00 chip and shorting switch.Code translator is selected a plurality of 74LS154 chips.Wherein 74LS154 is 4-16 code translator, and two Enable Pins are all Low level effectives, and four signal incoming levels have determined the output pin of low level signal.According to the arrangement of level, select the output pin of chip selection signal.The net result of decode procedure is to control by PCL address wire, and the data transmission of Jiang Ge road A/D chip is to PCL bus.16 bit data of Yao Shi 64 tunnels after A/D conversion are transferred to PCL data line simultaneously, need to after decoding link, increase data buffering link.

Adopt 74LS244 as PCL data buffer.74LS244 is 8 input 8 output triggers, and sheet choosing end is at Low level effective, and its input end is directly connected with eight parallel pins in 16 A/D chips, and output terminal is connected with PCL data line, and sheet choosing end is connected with the output terminal of code translator.Code translator is selected input by the timesharing of the low four bit address lines of PCL, forms 8 low level outputs in turn of output terminal, to form the triggering of 8 data trigger piece choosing ends.Finally, by data buffer, on PCL data line, also can obtain successively most-significant byte and the least-significant byte signal of 64 A/D chips.PCL data line input structure is as Fig. 4.

3, amplification filtering module

Amplification filtering module is multistage, and to be digital processing system amplify and the circuit module of filtering sensor output voltage multistage amplification filtering module, and the final voltage producing of this module finally inputs to A/D modular converter.Therefore, amplification filtering module is the basis of A/D modular converter, and the degree of stability of this module is related to the precision of whole system.The design proposal of amplification filtering module is: through calculating the millivolt signal that sensor is produced, amplify, by reference voltage, amplifying circuit output valve is adjusted, by wave filter, to entering the voltage of A/D modular converter, carry out active power filtering.In Design enlargement filtration module, except selecting amplifier of fine qualities, wave filter and before millivolt signal amplification, first carry out R/C filtering circuit, also to calculate enlargement factor.Wherein secondary filter amplifying circuit be in simulating signal after A/D transforms, before entering computing machine, amplify again, be equipped with the three rank ButterWorith-Bessel compound filters that RC forms, effectively reduce the interference of ripple to sampled data, guarantee the harmony of amplitude-frequency and phase frequency.Multistage filtering and amplifying circuit structure is as Fig. 5.

Sensitivity S=the 1.0mV/V of sensor; Power module selection ± 5V is as supplying bridge voltage, i.e. input voltage Vi=10V.So, Vo=Vi * S=10mV.If select the A/D chip of 0～5V voltage range of receiving, at least need in theory to amplify 300 times; And in design, consider and change the sensor of different sensitivity coefficient and the impact of Voltage Feedback, accurate enlargement factor.Reference voltage has non-reaction type and two kinds of producing methods of reaction type.Non-reaction type is using digitally as the benchmark of amplifier, and the voltage by INA128 is relatively; Reaction type is the benchmark using 2.5V as amplifier, by relative this 2.5V of voltage of INA128.For zero-point voltage, be positive passage, can apply non-reaction type; And be negative passage for zero-point voltage, must be by the output of reaction type guarantee full scale and linear accurately.In addition, digital processing system selects the precision resistance of 300 Ω as the amplification resistance of INA128, by formula, finally can amplify 152 times.Dui64 road sensor signal is carried out gain-adjusted so respectively, the consistance that keeps No. 64 sensors, effectively reduce the signal errors that the mechanical problem because of compound transducer produces, realize the stability of sensor output signal, improve dynamic weighing data accuracy.

Digital processing system selects INA128 as amplifier, and OPA2227 is as wave filter and reference voltage follower.INA128 is the general purpose instrument amplifier of low power consumption high-precision, and it is become by three Gong Tong Group of amplifier institute, forms differential amplification, and its enlargement factor finally depends on the resistance of external feedback resistance.OPA2227 is two-way amplifier, integrated two amplifier A and B in inside.Amplifier A carries out active power filtering to amplifying signal; Amplifier B is as voltage follower, stable reference voltage.

4, A/D modular converter design

A/D modular converter is that digital processing system is realized analog-to-digital circuit module, and the input signal of A/D modular converter is the voltage signal through amplification filtering module, and output terminal is some bit binary number signals.

In the A/D of digital processing system modular converter, be mainly to design a kind ofly should meet dynamic railway truck scale sampling rate faster, reach higher conversion accuracy, the circuit that can transmit PCL data line simultaneously.In order to meet above requirement, first to select suitable A/D conversion chip, this chip must be biproduct somatotype, parallel output, conversion accuracy is more than 16.We select ADS7821 as A/D conversion chip, and it has following features:

1), 16 bit parallel outputs

2), p.s. 100KHZ slewing rate

3), the input voltage range of 0 arrive+5V

4) DC-voltage supply of ,+5V

5), the coexistance model of internal reference voltage and external reference voltage

Under DOS environment, program is not subject to the impact of the sequential such as computing machine interruption, can directly to digital processing system, operate.Therefore, design the specific program that a set of compound sensor dedicated processes system is moved under DOS environment, under Windows operating system, realize driving, testing hardware.Under DOS environment, grammer Data=inportb (Addr) in application Turbo C can obtain exporting translation data, wherein Addr is device address, and in the design of Turbo c program, inportb (7F0) can control 74LS221 chip and produce the needed low level of R/C pin.Flow path switch when CS is low level is as Fig. 6.

Claims (1)

1. a compound sensor signal special digital disposal system, is characterized in that: it is by LOAD CELLS, amplification filtering module, A/D modular converter, code translator and the electric circuit constitute that is connected thereof; Described LOAD CELLS Wei64 road; LOAD CELLS, amplification filtering module, A/D modular converter, impact damper, secondary filter amplification module are connected successively, and are connected with industrial computer by PCL data bus;

Described code translator one end is connected with PCL data bus, and the other end selects device to be connected with level trigger by sheet; Described level trigger is connected on A/D modular converter.