CN101729330A - High-precision AD conversion circuit and working method thereof - Google Patents

High-precision AD conversion circuit and working method thereof Download PDF

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Publication number
CN101729330A
CN101729330A CN200810172368A CN200810172368A CN101729330A CN 101729330 A CN101729330 A CN 101729330A CN 200810172368 A CN200810172368 A CN 200810172368A CN 200810172368 A CN200810172368 A CN 200810172368A CN 101729330 A CN101729330 A CN 101729330A
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data
conversion chip
circuit
precision
networking
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CN200810172368A
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CN101729330B (en
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池立勇
黄伟杰
左新
白涛
朱毅明
柏祥基
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China Techenergy Co Ltd
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China Techenergy Co Ltd
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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P90/00Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
    • Y02P90/02Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

The invention relates to an AD conversion circuit, in particular to an AD conversion circuit used on a nuclear power station CAN network. The AD conversion circuit comprises a master control element, one end of the master control element is communicated with the CAN network and provides data for the CAN network, and the other end of the master control element is connected with an analog signal end through an AD conversion chip; and the AD conversion circuit also comprises a temperature compensation module connected with the AD conversion chip and used for compensating the temperature and an interface protection circuit for protecting the whole AD conversion circuit. The invention simultaneously discloses a working method of the AD conversion circuit. By adopting the technical scheme, the invention provides the high-precision AD conversion circuit which is communicated with the CAN network, and the AD conversion circuit can work stably and efficiently under the condition of not reducing the device precision; and meanwhile, the invention provides the working method which is applied on the AD conversion circuit.

Description

The method of work that a kind of high-precision A change-over circuit and this circuit use
Technical field
The present invention relates to a kind of A/D convertor circuit, be meant a kind of A/D convertor circuit that is used on the nuclear power station CAN network especially.
Background technology
In the nuclear power application, because the equipment itself that produces nuclear power by plurality of devices, adopts the CAN network to finish each communication between installing usually.CAN (controller local area network) is actually the standard serial communication agreement, can effectively support the distributed real-time control that high safety grade is used.Its range of application covers from express network to multichannel is interconnected cheaply.In the Automobile Electronic Industry field, use the transfer of data that CAN realizes systems such as engine, transducer and antiskid brake, traffic rate is 1Mbp s.CAN comprises 3-tier architecture, i.e. destination layer, transport layer and physical layer.And for make this CAN network can and each analog machine of nuclear power station between transmission data and device parameter, A/D convertor circuit is necessary for the CAN net, because the CAN network also is a kind of digital network, but in existing technology, also there is not A/D convertor circuit can offer the safe and reliable A/D convertor circuit in nuclear power field, therefore, the present invention provides a kind of high-precision A change-over circuit that can use in the CAN network agile with regard to being based on above-mentioned reason, it can be in stable operation under the condition of high temperature, do not reduce the device precision, stability.
Summary of the invention
Goal of the invention of the present invention is to provide a kind of and the high-precision A change-over circuit CAN network-in-dialing, and this A/D convertor circuit can be in the condition that does not reduce the device precision, the work of stability and high efficiency; The invention provides the method for work that is applied on this A/D convertor circuit simultaneously.
In order to realize above-mentioned goal of the invention, the present invention adopts following technical scheme:
A kind of high-precision A change-over circuit; this A/D convertor circuit comprises a master element; the one end is communicated with the CAN networking and provides data to it; an other end is by AD conversion chip connection mode analog signal end, and this A/D convertor circuit also comprises temperature compensation module that is used for compensation temperature that is connected with this AD conversion chip and the interface protective circuit of protecting whole A/D convertor circuit.
Active or the passive analog quantity diverter switch that described interface protective circuit comprises the analog quantity isolating chip and is communicated with this chip, this analog quantity isolating chip also is communicated with the AD conversion chip.
Described temperature compensation module comprises the temperature sensor that is connected with described AD conversion chip, and this transducer is communicated with the AD conversion chip and the temperature that directly detection obtained is transferred to processing module in the AD conversion chip.
Described master element includes two CAN controllers, and these two CAN controllers are communicated with respectively with A, the B two parts at CAN networking by the CAN interface circuit respectively, adopts isolating chip to isolate between this CAN controller and the corresponding CAN interface circuit.
Described A/D convertor circuit adopts the DC/DC power supply directly to whole A/D convertor circuit and the power supply of CAN net.Described DC/DC power supply power pack adopts isolated form DC/DC module NDY2405S and two isolated form DC/DC module NME0505D.
Described master element also is provided with one group of programmable logic device that is used to store at least.
In order further to improve the stability of this A/D convertor circuit, this high-precision A change-over circuit adopts following method of work, it is characterized in that this method of work comprises:
The first step, master element in the initialization A/D convertor circuit and AD conversion chip;
Second step, by master element, detect the connection status of analog quantity input, if broken string, device is reported to the police, and checks A/D conversion chip state, gathers to be used for the AD data converted, carries out data transaction;
In the 3rd step, CAN networking A has Data Receiving, proceeds this section processes, otherwise CAN networking A Frame count pick up adds 1, when counting down to fixedly threshold values, initialization CAN networking A; Data are saved in the reception buffering area; Remove CAN Frame count pick up; Adjust and receive buffer pointer; According to accepting data, the judgment data type, response data, and enter the 4th step handling process;
In the 4th step, CAN networking B has Data Receiving, proceeds this section processes, otherwise CAN net B Frame count pick up adds 1, when counting down to fixedly threshold values, initialization CAN networking B; Data are saved in the reception buffering area; Remove CAN Frame count pick up; Adjust and receive buffer pointer; According to model selection, return the 3rd step latter and enter in next step processing;
In the 5th step, read the CAN networking data based data of A and calibrate; Return calibration data, when receiving the calibration end data, device resets.
Described method of work also comprises by temperature sensor the temperature parameter of surveying is transferred to the AD conversion chip, and by the AD conversion chip with temperature parameter be preset in that AD conversion chip processing module temperature inside parameter compares and corresponding corresponding as a result data be weighted on the data that original AD is converted to as amount of temperature compensation.
By adopting above-mentioned technical scheme, the invention provides a kind of and the high-precision A change-over circuit CAN network-in-dialing, this A/D convertor circuit can be in the condition that does not reduce the device precision, the work of stability and high efficiency; The invention provides the method for work that is applied on this A/D convertor circuit simultaneously.
Description of drawings
What show among Fig. 1 is the general illustration that A/D convertor circuit of the present invention is connected with the CAN network;
What show among Fig. 2 is the general illustration of A/D convertor circuit internal structure of the present invention;
What show among Fig. 3 is the syndeton schematic diagram of interface protective circuit of the present invention;
Embodiment
The invention provides the well-informed high-precision A change-over circuit of a kind of and CAN network and have temperature-compensation circuit, stable operation does not at high temperature reduce device precision, A/D convertor circuit that stability is high.
What wherein show among Fig. 1 is the schematic diagram that A/D convertor circuit of the present invention is connected with the CAN network; Destination layer and transport layer realize all functions of the data link layer of ISO/OSI model definition in the CAN network.It is actual transmissions how that physical layer has defined signal.For transmission medium and signal level can further be optimized in actual applications, in the technical specification book of CAN Version2.0, physical layer is not defined.Transport layer is the core of CAN agreement, and the transmission of messages that receives is arrived destination layer, receives the message from destination layer simultaneously.Transport layer realize data bit regularly, synchronously, the message framing, arbitrate, reply, error detection, sign be definite with fault.What be communicated with the CAN networking at first is the CAN control that is used to read data in the CAN network, comprises CAN transceiver and controller.This CAN control then is communicated with AD conversion chip and other configuring chip by master element, and the master element here generally adopts microprocessor, and the kind of configuring chip then is varied, has not here just given unnecessary details.Among Fig. 1 then simple displaying the general illustration that is connected with the CAN network of A/D convertor circuit of the present invention.And the transmission course in the A/D convertor circuit of whole signal in Fig. 1 is as follows, the data of communication are transferred in the microprocessor by the CAN transceiver and under the control of CAN controller in the CAN network, data are transferred in the AD conversion chip by the initialization process of microprocessor, the AD chip is configured, analog quantity in the analogue system is amplified by signal amplification circuit and is transferred in the AD conversion chip, and AD conversion and a series of processing by microprocessor are transferred to the CAN network by the CAN transceiver again.
What show among Fig. 2 is the overall schematic of A/D convertor circuit internal structure of the present invention, wherein this A/D convertor circuit comprises a master element, the one end is communicated with the CAN networking and provides data to it, an other end receives the digital signal of changing by the AD conversion chip, and this AD conversion chip also is connected with the temperature-compensation circuit that is used for compensation temperature.This master element includes two CAN controllers, and these two CAN controllers are communicated with respectively with A, the B two parts at CAN networking by the CAN interface circuit respectively.Adopt isolating chip to isolate between described CAN controller and the corresponding CAN interface circuit, the isolating chip here prevent since unexpected high pressure that produces and high electric current for the destruction of A/D convertor circuit.Described AD conversion chip directly is communicated with the analog signal end by interface protective circuit; active or the passive analog quantity diverter switch that this interface protective circuit comprises the analog quantity isolating chip and is communicated with this chip, this analog quantity isolating chip also is communicated with the AD conversion chip.It is as follows to the function that whole A/D convertor circuit plays a very good protection: consist of example with passive analog quantity diverter switch LCC 120 and analog quantity isolating chip AD210BN in the interface protective circuit among following Fig. 3; insert above-mentioned analog quantity isolating chip AD210BN after the passive analog quantity diverter switch LCC120 of the analog quantity input process conducting, through inserting the AD conversion chip behind the analog quantity isolating chip AD210BN.The function of this interface protective circuit comprises internal defencive function and external defencive function.Internally defencive function is meant the on-site signal as the analog quantity input, because disturb, bigger voltage may occur, analog quantity isolating chip AD210BN carries out wave absorption and electrical isolation to the overvoltage signal, and interference signal can not impacted this circuit.(any fault that may occur when externally defencive function is meant this fault; comprise theoretic fault); when this circuit detects fault by hardware circuit and firmware logic, can switch, on-site signal and this circuit be no longer included be electrically connected by passive analog quantity diverter switch LCC120.If this circuit is complete failure; can not switch passive analog quantity diverter switch LCC120; isolation features according to analog quantity isolating chip AD210BN; do not have yet on-site signal is had electric influence; the most dangerous situation is that logical circuit and firmware logic can not have been switched passive analog quantity diverter switch LCC120 and analog quantity isolating chip AD210BN and damage or burn; failure mode analysis (FMA) according to analog quantity isolating chip AD210BN; analog quantity isolating chip AD210BN meeting and on-site signal short circuit; protected on-site signal, the function and the realization of Here it is interface protective circuit.
This A/D convertor circuit also comprises temperature compensation module in addition, and it comprises the temperature sensor that is connected with described AD conversion chip, and this transducer is communicated with the AD conversion chip and the temperature that directly detection obtained is transferred to processing module in the AD conversion chip.By temperature sensor the temperature parameter of surveying is transferred to the AD conversion chip, and by the AD conversion chip with temperature parameter be preset in that AD conversion chip processing module temperature inside parameter compares and will be weighted on the data that original AD is converted to as amount of temperature compensation with the corresponding data of result, certainly above-mentioned compensation rate for can on the occasion of or negative value all be possible, be the LM35 chip with the temperature sensor in the present embodiment again.
Described A/D convertor circuit adopts the DC/DC power supply directly to whole A/D convertor circuit and the power supply of CAN net, and one group of programmable logic device also is set in described master element in addition at least.Because the reliability of power supply design directly influences the performance of system, so above-mentioned system's power pack adopts the isolation of isolated form DC/DC module NDY2405S implement device and system power supply.Adopt 2 isolated form DC/DC module NME0505D to realize the isolation of CAN network and device.Analog circuit adopts 2 isolated form DC/DC module NMH2415D.And 16 single-chip microcomputers of the MC9S12DG128 of preferred freescale company are as master element.And above-mentioned master element has two CAN control chips, by high-speed light idol isolating chip 6N137 and CAN interface chip, realizes CAN net circuit, realizes the redundancy CAN net.The AD conversion chip preferably adopts AD7707BR, temperature sensor chip LM35, isolated amplifier AD210BN.Multidiameter option switch adopts LM319, high precision reference source to adopt MAX6325CAS.Wherein in-site modeling signal or a reference source signal select one road signal (to realize acquisition function when selecting the in-site modeling signal by multidiameter option switch; realize online calibration function when selecting the high precision reference source); after isolation, signal adjustment and the on-site signal protection through isolated amplifier; change digital quantity into by AD chip dress; temperature sensor chip is eliminated the influence that variations in temperature produces the AD conversion chip by measuring the signal of telecommunication that temperature obtains.
Store in the above-mentioned master element in order to realize the program of the whole A/D convertor circuit course of work, wherein after this program start operation, enter system initialization, carry out following steps:
The master element initialization; Read the data of programmable logic device EEPROM storage, data are detected, data are correct, and device is operation normally, otherwise report to the police; Hardware is detected, and hardware is correct, and device is operation normally, and device is reported to the police; Acceptance enters operational mode or on-line calibration pattern from the CAN networking command according to command selection, enters main control process flow then.
Main control process flow: after above-mentioned flow processing finishes, enter main control process flow.Main flow comprises 4 major parts, and circulation is carried out, and is respectively according to processing sequence: (a) analog acquisition; (b) CAN net A communication; (c) CAN net B communication; (d) Ethernet data sends part.Detailed process with top is as follows:
(a) analog acquisition; Detect analog quantity input signal cable connection status, if short-term, device is reported to the police, and checks A/D conversion chip state, gathers the A/D translation data, according to the range configuration, carries out data transaction, enters (b) flow process.
(b) CAN net A Data Receiving part; If CAN net A has Data Receiving, proceed this section processes, otherwise CAN net A Frame count pick up adds 1, if count down to 500ms, initialization CAN nets A; Data are saved in the reception buffering area; Removing CAN Frame count pick up adds; Adjust and receive buffer pointer; According to accepting data, the judgment data type echoes and answers data, enters (c) handling process;
(c) timer overflows the processing section; If CAN net B has Data Receiving, proceed this section processes, otherwise CAN net B Frame count pick up adds 1, if count down to 500ms, initialization CAN nets B; Data are saved in the reception buffering area; Removing CAN Frame count pick up adds; Adjust and receive buffer pointer; According to model selection, if whole A/D convertor circuit is in next step (a) handling process of returning of operational mode; If whole A/D convertor circuit is in next step (d) handling process that enters of online calibration mode;
(d) Ethernet data sends part.Reading the data based data of network A calibrates; Return calibration data, if receive that master element is controlled whole A/D convertor circuit and resetted under the condition of calibration end data.
By the A/D convertor circuit of such setting, it gathers single channel current type or voltage-type analog quantity, data is sent to other device of nuclear power station by the CAN network.
Two kinds of mode of operations of above-mentioned A/D convertor circuit: comprise operational mode and on-line calibration pattern.Under operational mode, every 25ms gathers an analog signals, monitors in real time and judges signal condition, according to order data and signal condition are sent to the CAN networking simultaneously, communication of monitoring redundancy CAN networking and diagnostic state if find CAN networking fault, are attempted communication again in real time; Under the on-line calibration pattern, according to order, acquisition channel is detected or verification from the CAN networking, simultaneously testing result is dealt into the CAN networking, and can be by the diagnosis from CAN networking, ethernet data frame is come the decision network state.
By adopting above-mentioned technical scheme, the invention provides a kind of and the high-precision A change-over circuit CAN network-in-dialing, this A/D convertor circuit can be in the condition that does not reduce the device precision, the work of stability and high efficiency; The invention provides the method for work that is applied on this A/D convertor circuit simultaneously.
Protection scope of the present invention is not limited to the content put down in writing in the above-mentioned specification specific embodiment in addition, as long as but the combination of satisfying technical characterictic in claims of the present invention just fallen among protection scope of the present invention.

Claims (9)

1. high-precision A change-over circuit; it is characterized in that; this A/D convertor circuit comprises a master element; the one end is communicated with the CAN networking and provides data to it; an other end is by AD conversion chip connection mode analog signal end, and this A/D convertor circuit also comprises temperature compensation module that is used for compensation temperature that is connected with this AD conversion chip and the interface protective circuit of protecting whole A/D convertor circuit.
2. a kind of high-precision A change-over circuit according to claim 1; it is characterized in that; active or the passive analog quantity diverter switch that described interface protective circuit comprises the analog quantity isolating chip and is communicated with this chip, this analog quantity isolating chip also is communicated with the AD conversion chip.
3. deadweight high-precision A change-over circuit according to claim 1, it is characterized in that, described temperature compensation module comprises the temperature sensor that is connected with described AD conversion chip, and this transducer is communicated with the AD conversion chip and the temperature that directly detection obtained is transferred to processing module in the AD conversion chip.
4. a kind of high-precision A change-over circuit according to claim 1, it is characterized in that, described master element includes two CAN controllers, these two CAN controllers are communicated with respectively with A, the B two parts at CAN networking by the CAN interface circuit respectively, adopt isolating chip to isolate between this CAN controller and the corresponding CAN interface circuit.
5. a kind of high-precision A change-over circuit according to claim 1 is characterized in that, described A/D convertor circuit adopts the DC/DC power supply directly to whole A/D convertor circuit and the power supply of CAN net.
6. a kind of high-precision A change-over circuit according to claim 5 is characterized in that, described DC/DC power supply power pack adopts isolated form DC/DC module NDY2405S and two isolated form DC/DC module NME0505D.
7. a kind of high-precision A change-over circuit according to claim 1 is characterized in that described master element also is provided with one group of programmable logic device that is used to store at least.
8. according to the method for work of the described high-precision A change-over circuit of claim 1-7, it is characterized in that this method of work comprises:
The first step, master element in the initialization A/D convertor circuit and AD conversion chip;
Second step, by master element, detect the connection status of analog quantity input, if broken string, device is reported to the police, and checks A/D conversion chip state, gathers to be used for the AD data converted, carries out data transaction;
In the 3rd step, CAN networking A has Data Receiving, proceeds this section processes, otherwise CAN networking A Frame count pick up adds 1, when counting down to fixedly threshold values, initialization CAN networking A; Data are saved in the reception buffering area; Remove CAN Frame count pick up; Adjust and receive buffer pointer; According to accepting data, the judgment data type, response data, and enter the 4th step handling process;
In the 4th step, CAN networking B has Data Receiving, proceeds this section processes, otherwise CAN net B Frame count pick up adds 1, when counting down to fixedly threshold values, initialization CAN networking B; Data are saved in the reception buffering area; Remove CAN Frame count pick up; Adjust and receive buffer pointer; According to model selection, return the 3rd step latter and enter in next step processing;
In the 5th step, read the CAN networking data based data of A and calibrate; Return calibration data, when receiving the calibration end data, whole A/D convertor circuit resets.
9. method of work according to claim 8, it is characterized in that, described method of work also comprises by temperature sensor the temperature parameter of surveying is transferred to the AD conversion chip, and by the AD conversion chip with temperature parameter be preset in that AD conversion chip processing module temperature inside parameter compares and will be weighted on the data that original AD is converted to as amount of temperature compensation with the corresponding data of result of detection.
CN2008101723680A 2008-11-03 2008-11-03 High-precision AD conversion circuit and working method thereof Active CN101729330B (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
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CN105570510A (en) * 2014-11-06 2016-05-11 南通大学 Electro-hydraulic type valve intelligent controller used for ship
CN105971976A (en) * 2016-05-25 2016-09-28 广西柳工机械股份有限公司 Method for measuring hydraulic pressure of engineering machine by means of voltage type pressure sensor

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US6910381B2 (en) * 2002-05-31 2005-06-28 Mykrolis Corporation System and method of operation of an embedded system for a digital capacitance diaphragm gauge
JP4843347B2 (en) * 2006-03-31 2011-12-21 旭化成エレクトロニクス株式会社 Receiving system
CN200939664Y (en) * 2006-08-15 2007-08-29 三一重工股份有限公司 Weighting senser information acquisition device for agitating station

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Publication number Priority date Publication date Assignee Title
CN105570510A (en) * 2014-11-06 2016-05-11 南通大学 Electro-hydraulic type valve intelligent controller used for ship
CN105971976A (en) * 2016-05-25 2016-09-28 广西柳工机械股份有限公司 Method for measuring hydraulic pressure of engineering machine by means of voltage type pressure sensor

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