CN103049984B - Combustible gas alarm instrument based on Wireless HART communication technology - Google Patents

Abstract

The invention discloses a combustible gas alarm instrument based on Wireless HART communication technology. The alarm instrument comprises an MSP430 (Message Send Protocol 430) singlechip microcomputer which is respectively connected to a signal conditioning circuit and a WIA (Windows Image Acquisition) wireless communication module through different ports; the signal conditioning circuit is connected with a combustible gas sensor; the combustible gas sensor detects the concentration of combustible gas, and converts the concentration into a corresponding electric signal; after being amplified by the signal conditioning circuit, the electric signal is input to the singlechip microcomputer; the singlechip microcomputer performs analog-to-digital conversion on the input signal to obtain corresponding digital amount; whether the digital amount reaches an alarm value or not is judged through data analysis and threshold comparison, and if the digital amount reaches the alarm value, an alarm signal is transmitted to a WIA wireless communication module through a full duplex serial port; and the WIA wireless communication module adopts a WIAPA-M1800 wireless adaptor. A cable is not required to be paved, and the combustible gas alarm instrument has the advantages of very strong anti-interference ability, super-low power consumption, real-time wireless communication and the like.

Description

Combustible gas alarming instrument based on the Wireless HART communication technology

Technical field

The present invention relates to high-acruracy survey and Real-Time Monitoring field, a kind of combustible gas alarming instrument specifically, combustable gas concentration in enterprise's generative processes such as petrochemical complex is accurately detected, and can pass through Wireless HART(wireless HART communication protocol) detecting instrument of communication mode real-time Transmission, be adapted at using in severe industrial environment.

Background technology

In commercial production; no matter be to produce, process raw material or fuel; often have some inflammable gass; as hydrogen, methane and liquefied petroleum gas (LPG) etc.; once these gases occur to leak, be easy to cause burning or even blast; when serious, can cause casualties and property loss, so combustible gas alarming instruments particular importance that just seems is installed in these occasions.But combustible gas alarming instrument generally adopts wired mode transmission detection signal at present.In wired connection mode, exist following problem: 1, difficult in maintenance, cost is high.When cable line breaks down or will change circuit, the cable laying again that is bound to, this one side site operation is had any problem, and original circuit is abandoned and cannot be utilized on the other hand, causes waste to increase cost.2, very flexible.After Sampling network sets up, change is suitable difficulty, and increase equipment is laid more cable again, along with the growth in age, even there will be that cable line is saturated cannot lay the such problem of more cable more again.3, narrow application range.The application scenario that wired mode is wide for region, equipment disperses is also inapplicable, because cable laying difficulty greatly and not too convenient.Obviously, adopt the demand of wireless mode more and more urgent, the fact also proves simultaneously, and radio network technique is more conducive to the control and management of field data.

At present, wireless network is with the application focus of advantage the becoming industrial control field such as its networking flexibility, small investment, maintenance be simple.The radio network technique of applying in industrial control field has several, Wireless HART agreement wherein has good compatibility to existing HART equipment instrument, it is a kind of wireless mesh type network communication protocol designing for industrial process automation application specially, take HART agreement as basis, employing works in 2.4GHz ISM(Industrial Scientific Medical industry, science, medical science) radio frequency band, there is safe, sane network topology networking technology.The back compatible of the Wireless HART communication technology is in existing HART equipment instrument, and carried out function and supplemented and application extension, and existing HART application, without carrying out any software upgrading, can utilize Wireless HART agreement.

Summary of the invention

The present invention is directed to the existing deficiency existing with the Combustible Gas Alarm Device of wired mode signal transmission, propose a kind of combustible gas alarming instrument based on the Wireless HART communication technology, Maintenance free, cost is low, dirigibility good, applied widely.

The technical solution used in the present invention is: comprise MSP430 single-chip microcomputer, MSP430 single-chip microcomputer connects respectively signal conditioning circuit and WIA wireless communication module by different ports, and signal conditioning circuit connects combustible gas sensor; Described combustible gas sensor detects the concentration of inflammable gas, converts corresponding electric signal to and amplifies and process to signal conditioning circuit, and the signal after amplification is input to MSP430 single-chip microcomputer; Described MSP430 single-chip microcomputer carries out analog to digital conversion to the signal of input, obtains corresponding digital quantity, through data analysis, threshold value comparison, judges whether to reach alarming value, if reach, alerting signal is sent to WIA wireless communication module by full duplex serial ports; Described WIA wireless communication module adopts WIAPA-M1800 wireless adapter, in Wireless HART mode, data are sent to host computer, carry out send and receive serial data, a command interface of synchronized timestamp information, local configuration information and diagnostic message is provided; All messages between described MSP430 single-chip microcomputer and described WIAPA-M1800 are all controlled HDLC packet format framing with data link, each orders into a frame correspondence, the start bit that comprises 1 byte, the information of n byte, the cut-off position of 1 byte of check bit sum of 2 bytes, has comprised command number and data in information.

The present invention, without cable laying, is conducive to the control and management of field data.There is the advantages such as very strong antijamming capability, super low-power consumption, real-time radio communication; Be applicable to the application scenario that region is wide, equipment disperses, be also adapted at severe industrial environment and use.

Accompanying drawing explanation

Fig. 1 is the hardware configuration schematic diagram that the present invention is based on the combustible gas alarming instrument of the Wireless HART communication technology;

Fig. 2 is the structural drawing of signal conditioning circuit in Fig. 1;

Fig. 3 is the application circuit schematic diagram of WIA wireless communication module in Fig. 1;

Fig. 4 is HDLC packet format schematic diagram;

In figure: 5.MSP430 single-chip microcomputer; 6. combustible gas sensor; 7. signal conditioning circuit; 8. chip external memory; 9. key circuit; 10 .WIA wireless communication modules; 11. sound light alarming circuits; 12.LCD display; 13. power supplys.

Embodiment

As shown in Figure 1, the present invention includes MSP430 single-chip microcomputer 5, MSP430 single-chip microcomputer 5 connects respectively signal conditioning circuit 7, chip external memory 8, key circuit 9, WIA wireless communication module 10, sound light alarming circuit 11, LCD display 12 and power supply 13 by different ports.Signal conditioning circuit 7 connects combustible gas sensor 6.The inflammable gas sensing probe of combustible gas sensor 6 is installed at alarm shell upper end open place, LCD display 12 and button are installed by front openings place, WIA wireless communication module 10 and main controller circuit plate are installed by portion in the enclosure, and wireless antenna is installed at shell right openings place.

By combustible gas sensor 6, detect the concentration of inflammable gas, and convert corresponding electric signal V to _oUT, the Header2 input end that is connected to signal conditioning circuit 7 by signal wire amplifies processing, then signal is input to MSP430 single-chip microcomputer 5, MSP430 single-chip microcomputer 5 is built-in with 16 A/D unit, A/D unit carries out analog to digital conversion to the signal of input, obtain corresponding digital quantity, data analysis through MSP430 single-chip microcomputer 5, threshold value comparison, judge whether to reach alarming value, if reach, alerting signal is sent to WIA wireless communication module 10 by full duplex serial ports, and then in Wireless HART mode, data are sent to the alarm platform of host computer by WIA wireless communication module, realize wireless remote alarming, simultaneously, also with sound light alarming circuit 11, carry out traditional sound and light alarm, and measurement data is stored by chip external memory 8, by LCD display 12, show, power supply 13 adopts 3.3V lithium battery power supply.In main controller circuit plate, use 3.3V to turn 3V gate-controlled switch chip and provide required power supply to simulation part and numerical portion.Key circuit 9 is realized the functions such as system reset, Threshold.

Signal conditioning circuit as shown in Figure 2, adopts high precision instrumentation amplifier LTC2053, and the output electrical signals of combustible gas sensor TGS6812 is carried out to high-precision amplification processing.The input off-set voltage of LTC2053 is 10 μ V to the maximum, and common-mode rejection ratio CMRR and Power Supply Rejection Ratio PSRR can reach 116dB.Working power adopts low-voltage 2.7V power supply, and current sinking is very low, and representative value is 85 μ A, meets low-power consumption requirement, adopts 3.3V lithium battery power supply.

In Fig. 2, being connected the input electrical signal of amplifier TGS6812, capacitor C 17(102 with No. 2 pins socket Header2 No. 1) end receives No. 1 pin of socket, and the other end is received No. 2 pins of socket; Resistance R 2(10K) end is received No. 2 pins of socket, and the other end is received No. 2 pins of LTC2053; Resistance R 3(10K) end is received No. 1 pin of socket, and the other end is received No. 3 pins of LTC2053; Resistance R 5(10M) end is received No. 8 pins of LTC2053, and the other end is connected with resistance R 6, R8; Resistance R 6(10M) one end is connected with resistance R 5, R7, R8, other end ground connection; Resistance R 7(1M) one end is connected with resistance R 5, R6, R8, and No. 1 pin of the other end and socket is connected; Resistance R 8(1M) one end is connected with resistance R 5, R6, R7, and No. 2 pins of the other end and socket are connected; Capacitor C 15(102) No. 1 pin in one end and socket is connected, other end ground connection; Capacitor C 16(102) No. 2 pins in one end and socket are connected, other end ground connection; Resistance R 4(10 Ω) a termination LTC2053 No. 6 pins, other end ground connection; Capacitor C _ feedback(104) a termination LTC2053 No. 6 pins, No. 7 pins of another termination LTC2053; Adjustable resistance Radj_1(100 Ω) No. 6 pins of a termination LTC2053, the other end and middle pin connect No. 7 pins of LTC2053; No. 1, No. 4 pin ground connection of LTC2053; Adjustable resistance Radj_2(100 Ω) No. 1 pin of a termination LTC2053, No. 5 pins of another termination LTC2053, middle pin connects No. 8 pins of LTC2053; No. 8 pins of LTC2053 connect 3.3V power supply.Capacitor C 15 and C16 contribute to the sampling that the output terminal that absorbs Radio frequency interference (RFI) and be suppressed at TGS6812 occurs to disturb.In feedback circuit, increased the response that capacitor C _ feedback can add speed amplifier.Resistance R 5～R8 provides high impedance biasing, can the in the situation that of input signal absence of voltage, make its anti-interference reach maximum.By regulating Radj_1 and R4 conveniently to programme to circuit gain.

MSP430 single-chip microcomputer 5 kernels are 16 risc processors, single command cycle, its arithmetic capability and speed and realize and in super low-power consumption characteristic, all have certain advantage.Inner integrated 16 A/D converter controllers of MSP430F425, lcd controller and FLASH controller reduce working time of CPU on software by park mode, can move power consumption control at microampere order.

WIA wireless communication module 10 adopts the WIAPA-M1800 wireless adapter with the Wireless HART communication technology, WIAPA-M1800 is a kind of low energy consumption, short-distance wireless communication equipment, is operated in the free 2.4GHz frequency range based on industrial standard 802.15.4 in the whole world.WIAPA-M1800 is integrated SIA2420 wireless module and WIA-PA core protocol, can connect field instrument equipment, make its can access of radio network in, and possess network routing function, in Wireless HART mode, carry out data communication.

The serial ports P3.7/RXD that MSP430 single-chip microcomputer 5 provides with WIAPA-M1800 respectively with P3.5/URXD0 pin by full duplex serial ports P3.4/UTXD0 is connected with P3.6/TXD pin, and WIAPA-M1800 application circuit schematic diagram as shown in Figure 3.Serial ports transformation parameter is 1 start bit, 8 bit data positions and 1 position of rest, and baud rate is 9600.By this port, WIAPA-M1800 can carry out send and receive serial data by wireless network, and the command interface that synchronized timestamp information, local configuration information and diagnostic message are provided.

All messages between MSP430 single-chip microcomputer 5 and WIAPA-M1800 are all with High-Level Data Link Control HDLC(High level Data Link Control) packet format framing, each orders into a frame correspondence.HDLC packet format as shown in Figure 4.The start bit that comprises 1 byte (0X7E), the information of n byte (HDLC load), the cut-off position (0X7E) of 1 byte of check bit sum of 2 bytes, has wherein comprised command number and data in information.Command number accounts for 1 byte, and main command number has 0x11 to represent write device Network ID, and 0x12 represents to read equipment Network ID, 0x13 represents to arrange device mac address, 0x14 represents fetch equipment MAC Address, and 0x17 represents that data transparency uploads, and 0x18 represents that data transparency issues.

Claims (1)

1. the combustible gas alarming instrument based on the Wireless HART communication technology, described combustible gas alarming instrument comprises MSP430 single-chip microcomputer, MSP430 single-chip microcomputer connects respectively signal conditioning circuit and WIA wireless communication module by different ports, and signal conditioning circuit connects combustible gas sensor; Described combustible gas sensor detects the concentration of inflammable gas, converts corresponding electric signal to and amplifies and process to signal conditioning circuit, and the signal after amplification is input to MSP430 single-chip microcomputer; Described MSP430 single-chip microcomputer carries out analog to digital conversion to the signal of input, obtains corresponding digital quantity, through data analysis, threshold value comparison, judges whether to reach alarming value, if reach, alerting signal is sent to WIA wireless communication module by full duplex serial ports;

Described WIA wireless communication module adopts WIAPA-M1800 wireless adapter, in Wireless HART mode, data are sent to host computer, carry out send and receive serial data, a command interface of synchronized timestamp information, local configuration information and diagnostic message is provided; All messages between described MSP430 single-chip microcomputer and described WIAPA-M1800 are all controlled HDLC packet format framing with data link, each orders into a frame correspondence, the start bit that comprises 1 byte, the information of n byte, the cut-off position of 1 byte of check bit sum of 2 bytes, in information, comprised command number and data, it is characterized in that:

Described signal conditioning circuit comprises amplifier LTC2053, the electric signal of No. 1 and No. 2 pin input combustible gas sensor TGS6812 of socket, and No. 1 pin of capacitor C 17 one end combination hub, the other end is received No. 2 pins of socket; No. 2 pins of resistance R 2 one end combination hub, No. 2 pins of another termination LTC2053; No. 1 pin of resistance R 3 one end combination hub, No. 3 pins of another termination LTC2053; No. 8 pins of resistance R 5 one termination LTC2053, the other end is connected with resistance R 6, R8; Resistance R 6 one end are connected with resistance R 5, R7, R8, other end ground connection; Resistance R 7 one end are connected with resistance R 5, R6, R8, and No. 1 pin of the other end and socket is connected; Resistance R 8 one end are connected with resistance R 5, R6, R7, and No. 2 pins of the other end and socket are connected; No. 1 pin in capacitor C 15 one end and socket is connected, other end ground connection; No. 2 pins in capacitor C 16 one end and socket are connected, other end ground connection; No. 6 pins of resistance R 4 one termination LTC2053, other end ground connection; No. 6 pins of capacitor C _ feedback mono-termination LTC2053, No. 7 pins of another termination LTC2053; No. 6 pins of adjustable resistance Radj_1 mono-termination LTC2053, the other end and middle pin connect No. 7 pins of LTC2053; No. 1, No. 4 pin ground connection of LTC2053; No. 1 pin of adjustable resistance Radj_2 mono-termination LTC2053, No. 5 pins of another termination LTC2053, middle pin connects No. 8 pins of LTC2053; No. 8 pins of LTC2053 connect 3.3V power supply.