CN1128501C

CN1128501C - Twelve position mode/digit converting card

Info

Publication number: CN1128501C
Application number: CN 98126418
Authority: CN
Inventors: 吴效明; 岑人经; 胡道明
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 1998-12-25
Filing date: 1998-12-25
Publication date: 2003-11-19
Anticipated expiration: 2018-12-25
Also published as: CN1230053A

Abstract

The present invention relates to a twelve position analog-digital conversion card which is composed of an analog multi-way switch, an A/D converter, a PIC16 single chip microcomputer, a photoelectric isolation circuit, an FIFO memory, a GAL programmable logic circuit, etc., wherein the single chip microcomputer is adopted to control the time sequence of A/D conversion, and the FIFO memory is used as a data buffer. Visual programming control is realized in a Windows operating system without interrupting a working mode, accurate timing sampling can be realized, the signal waveform of a sampled object is displayed in a real-time mode, and the arranged photoelectric isolation circuit can ensure the high safety and the reliability of an established system. The present invention has the advantages of easy use and wide application scope.

Description

Twelve position mode/digit converting card

Technical field

The present invention relates to the vitals of COMPUTER DETECTION, control system, relate to be suitable for the twelve position mode/digit converting card that uses with each grade microcomputer analog signals collection of isa bus in more detail.

Background technology

Mould/number (analog quantity/digital quantity) transition card is the vitals that constitutes COMPUTER DETECTION, control system, and the mould that pattern is different/number conversion card just is being widely used in the various digital control apparatus.The interface circuit design of Universal Die/number conversion card generally all meets certain Industry Standard Architecture, as STD bus.Mould/number conversion card type the class that is applicable to the PC microcomputer at present is less, and the work schedule of mould/number conversion card generally all is the CPU that directly is controlled by main frame.Such mould/number conversion card is unfavorable for realizing programming Control under the Windows of multiple task management operating system, is difficult to guarantee data acquisition, the real-time that shows and control.

Summary of the invention

Purpose of the present invention is exactly in order to overcome above-mentioned shortcoming, and a kind of twelve position mode/digit converting card is provided, to adapt to the application program of current popular and the Windows environment of popularizing.

Realize that technical scheme of the present invention is as follows: twelve position mode/digit converting card is by analog multichannel switch, buffer amplifier, analog to digital converter, the PIC16 single-chip microcomputer, the TLP521 photoisolator, the FIFO memory, GAL Programmable Logic Device and data latches constitute, photoisolator inside is combined by light-emitting diode and phototriode, analog multichannel switch receives measured analog signal, high-frequency interferencing signal is carried out filtering and inhibition, output to buffer amplifier, receive analog to digital converter, analog quantity is carried out zero point to be adjusted and the full scale adjustment, the output digital signal is added to photoisolator, number of pulses is delivered to the FIFO memory according to after carrying out shaping; Single-chip microcomputer is accepted the instruction of microcomputer, and control is selected on sample road number of multi-way switch circuit, and the cue that sends is connected to Programmable Logic Device by photoisolator, delivers at last on the data/address bus of microcomputer; Microcomputer sends control command by latch to single-chip microcomputer, and data-signal is exported through photoisolator.

The present invention compared with prior art has following advantage:

1, twelve position mode/digit converting card of the present invention has oneself independently logic control circuit, and it can accept main frame about sampling road number, the instruction of sample frequency etc., and the data that sampling obtains send main frame to by one group of FIFO (first-in first-out) memory.

2, measurement, the control system of utilizing twelve position mode/digit converting card of the present invention to set up, fully can be under the Windows operating system environment, carry out programming with Visual Basic or with Visual C++, needn't consider to adopt interrupt mode, need only just can go the rounds sampling by inquiry mode to multichannel analog signals, accurately control sampling rate, and show the waveform of measured signal in real time;

3, twelve position mode/digit converting card of the present invention is owing to be provided with photoisolator, can set up the reliable system of high safety, when being used for industrial process measurement amount, can isolate of the interference of on-the-spot high voltage to computer, when being used for physiological signal measurements, but the isolation computer power supply reduces patient's leakage current to the influence of human body.

Description of drawings

Fig. 1 is the block diagram of twelve position mode/digit converting card of the present invention;

Fig. 2 is the circuit diagram of twelve position mode/digit converting card of the present invention;

Fig. 3 is the control timing schematic diagram of twelve position mode/digit converting card of the present invention.

The present invention will be described in more detail below by embodiment and accompanying drawing.

Embodiment

As shown in Figure 1, twelve position mode/digit converting card of the present invention is by analog multichannel switch, buffer amplifier, analog to digital converter, the PIC16 single-chip microcomputer, the TLP521 photoisolator, the FIFO memory, GAL Programmable Logic Device and data latches constitute, analog multichannel switch receives measured analog signal, high-frequency interferencing signal is carried out filtering and inhibition, output to buffer amplifier, receive analog to digital converter, analog quantity is carried out zero point to be adjusted and the full scale adjustment, the output digital signal is added to photoisolator, and number of pulses is delivered to the FIFO memory according to after carrying out shaping.Single-chip microcomputer is accepted the instruction of microcomputer, control is selected on sample road number of multi-way switch circuit, the cue that sends is connected to Programmable Logic Device by photoisolator, deliver at last on the data/address bus of microcomputer, microcomputer sends control command by latch to single-chip microcomputer, and data-signal is exported through photoisolator.

As shown in Figure 2, measured analog signal is received the input of analog multichannel switch IC circuit 1, R1-R8 among the figure, and C1-C8 plays the filtering inhibitory action to high-frequency interferencing signal; The output of variable connector behind buffer amplifier IC2, is received the analog quantity input of IC3 analog to digital converter AD574, and analog to digital converter connects according to bipolarity analog quantity input mode, carries out zero point with potentiometer W1 and adjusts, and potentiometer W2 carries out the full scale adjustment.The data way of output of AD574 is 12 conversions, 8 outputs at twice, outputting data signals is added to the signal input side of photoisolator IC7, IC8 through data buffering drive circuit IC6, certain time-delay and burr can take place in signal behind photoisolator, the data pulse is carried out delivering to after the shaping data input pin of FIFO memory IC 13 by IC11, IC12.

IC4 is the PIC16 single-chip microcomputer, its I/O terminal assignment is as follows: A0-A3 is an incoming line, acceptance is from the instruction of PC microcomputer, command content comprises the selection mode, sample frequency, self-defining contact password on sampling road number etc., so-called sampling road selection mode is promptly gone the rounds sampling according to what order to which road, and the contact password then can be used for object identification when needed or encrypted ones is set; B0-B7 is a delivery outlet, wherein B0-B2 receives variable connector IC1, control the selection on eight sampling roads number, B3 is the marker delivery outlet, and B3 produces " logic OR " with the data input pin DB4 of analog to digital converter IC3 by IC5 and is added back on the corresponding data bit of DB4, generally again, the data that do not influence DB4 transmit, only when touring sampling, when to the low four figures of initial road number sampling according to sending when effective just adding " 1 "; B4 is the output line of cue, and it is connected to Programmable Logic Device IC14 by photoisolator, delivers at last on the data/address bus of PC, to reply the contact password of PC; B5 exports a data write signal, and the data that it receives FIFO memory IC 13 by photoisolator write control end W, and mating die number conversion sequential produces and writes pulse, writes the FIFO memory during with analog-to-digital fructufy; B6 is connected to analog to digital converter A0 end, effectively select with low four outputs in order to the transition status of control analog to digital converter and the high eight-bit of control analog to digital converter data output, keep low level at transition period B6, promptly finish 12 conversions, the low four figures certificate of output is exported high four figures certificate during for " 0 " when converting back B6 for " 1 "; B7 is connected to the R/C* end of analog to digital converter, produces the pulse of conversion start-up control.

IC13 is an asynchronous FIFO memory, its data input pin is accepted the data from analog to digital converter, write signal end W, be subjected to the control of single-chip microcomputer IC4, its data output end is connected to the data/address bus of PC, and read output signal end R is connected to IC14, control by PC, its reset terminal RS, the empty sign of data EF end, the half-full sign of data HF end also all is connected to IC14.

IC14 is programmable logic device GAL20V8A, the function of executive address decoding and each control signal logical combination.IC14 accepts address signal and the read-write control signal IOR and the IOW of PC bus, also insert the flag bit EF and the HF of FIFO memory, 3 control signals have been combined into, with one group of status signal, F3 meets the RS of IC13, produces the reset signal of FIFO memory, F5 meets the CLK of IC18, produce output data strobe signal, F7 meets the R of IC13, produces the read output signal of FIFO memory.Three status signals are connected on the PC data/address bus with the ternary way of output: D0 is a FIFO memory data dummy status sign, and D1 is the half-full sign of FIFO memory data, and D2 is the cue by single-chip microcomputer IC4 output.

IC18 is 8 latchs, and PC sends control command to the PIC single-chip microcomputer by IC18, and digital signal needs export through photoisolator IC16, IC17 equally.

The output digital signal is after IC15 exports, and wherein CLEAR is the reset signal of single-chip microcomputer, and DATA6-DATA3 is the Single-chip Controlling instruction.DATA2-DATA0 is connected to accessory power outlet, can be used as the control logic of signal conditioning circuit.

Its basic technical indicator is:

Input signal way: 8 tunnel

Input signal range :-5-+5V

Analog-to-digital converter resolution: 12

Sample frequency: adjustable, single channel when sampling, reach 5000 times/S the soonest

The entire circuit of Fig. 2 is carried out under the PIC16C54 Single-chip Controlling, its control timing as shown in Figure 3, at first B0, B1, B2 produce the selection signal on road number, through suitable time-delay, analog signal settles out at the AD574 input, send negative pulse by B7 and start switching signal, begin a change-over period; In this cycle, about 38 μ S change-over time (the actual 25 μ S that need), in this transition period, B6 (being the A0 of AD574) is a low level, what promptly carry out is 12 conversions; After converting, B6 sends the low level control A0 of the high level of 80 μ S and 80 μ S, so that cooperate two of B5 to write pulse, low four and the high eight-bit of transformation result is delivered in the FIFO memory successively; When reading translation data, B0, B1, B2 have sent the gating signal on next road, get new one in advance ready and take turns conversion; B3 is added to a marker bit in the data, mould/number conversion card is that each data accounts for two bytes to the touring automatically sampling of multiple signals, and actual significance bit only accounts for 12, we are a mark on remembering on the data room of each touring starting symbol, is convenient to can sit in the right seat after PC reads in data.Insert an intermittent phase after each sampling circulation is finished, control sample frequency according to the length of intermittent phase.

The data input and output of FIFO memory are controlled respectively by single-chip microcomputer and PC microcomputer, play metadata cache.According to sample frequency of setting and sampling way, the data of mould/number conversion deposit the FIFO memory constantly, on schedule, in proper order in, data empty sign EF or the half-full sign of data HF that PC only need be inquired about the FIFO memory in time take the data that collected away.

Control Software with Visual C++ design has realized: in the parameter of main window menu the default definite value of the windowed format that can revise sample frequency, sampling road number in the option and show sample waveform etc. is set.After changing execution real-time sampling task over to, just can in the sampling display window, observe the real-time sampling waveform.At this moment, can respond following incident: suspend, stop sampling and freeze to show; Continue, restart sampling and continue display waveform; The data of gathering preserved in record, and the length of writing time need preestablish, and the data of record can be set up data file and use for analyzing to print; Wave amplitude amplifies/dwindles, and selects a certain signal, makes the amplitude amplification of its waveform or dwindle being beneficial to observe, and under the normal condition, the demonstration amplitude of waveform is self-adjusting; Stop (withdrawing from), finish the real-time sampling task.

Claims

1, a kind of twelve position mode/digit converting card, it is characterized in that by analog multichannel switch, buffer amplifier, analog to digital converter, the PIC16 single-chip microcomputer, the TLP521 photoisolator, the FIFO memory, GAL Programmable Logic Device and data latches constitute, photoisolator inside is combined by light-emitting diode and phototriode, analog multichannel switch receives measured analog signal, high-frequency interferencing signal is carried out filtering and inhibition, output to buffer amplifier, receive analog to digital converter, analog quantity is carried out zero point to be adjusted and the full scale adjustment, the output digital signal is added to photoisolator, number of pulses is delivered to the FIFO memory according to after carrying out shaping; Single-chip microcomputer is accepted the instruction of microcomputer, and control is selected on sample road number of multi-way switch circuit, and the cue that sends is connected to Programmable Logic Device by photoisolator, delivers at last on the data/address bus of microcomputer; Microcomputer sends control command by latch to single-chip microcomputer, and data-signal is exported through photoisolator.