CN102510352A - Industrial network terminal - Google Patents
Industrial network terminal Download PDFInfo
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- CN102510352A CN102510352A CN2011103383609A CN201110338360A CN102510352A CN 102510352 A CN102510352 A CN 102510352A CN 2011103383609 A CN2011103383609 A CN 2011103383609A CN 201110338360 A CN201110338360 A CN 201110338360A CN 102510352 A CN102510352 A CN 102510352A
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Abstract
The invention discloses an industrial network terminal, which comprises a central processing unit, a communication unit and a first isolation circuit. The communication unit is used for transmitting data between the terminal and a remote upper computer of the industrial network, the first isolation circuit is arranged on the industrial network terminal between the central processing unit and the communication unit and used for isolating electric signals between the central processing unit and the communication unit. Since the electric signals between the central processing unit and the communication unit are isolated, the problem of instability of communication of RTU (remote terminal unit) communication interfaces in the correlation technology is solved, and stability of the RTU communication interfaces can be improved.
Description
Technical field
The present invention relates to RTU, in particular to a kind of industrial network terminal.
Background technology
At present; Existing RTU RTU (Remote Terminal Unit on the market; Be called for short RTU) in the connection of I/O passage, often adopt common electrical connection, do not accomplish the comprehensive electrical isolation protection of real I/O passage, this connected mode can cause the damage of equipment usually.Such as, when the analog quantity input module is connected,, very easily burn the acquisition channel of analog quantity input module if field connection directly inserts the signal of telecommunication of 24V the terminal of analog quantity input module, equipment is caused irreversible damage.In the connection of communication interface, also communication interface not being done electrical isolation handles; Usually occur disturbing the situation that influences communication robust because of external electrical; Even occur because the unfavorable outer thereby situation of smashing communication interface causes irreversible damage to equipment equally.Simultaneously, because the close together and the communication speed of RS-232 or RS-485 serial communication are lower, therefore, only the RTU with serial ports receives than limitations in the networking at the scene, uses inconvenient.
To RTU communication interface communication situation problem of unstable in the correlation technique, effective solution is not proposed as yet at present.
Summary of the invention
Main purpose of the present invention is to provide a kind of industrial network terminal, to solve RTU communication interface communication situation problem of unstable.
To achieve these goals, according to an aspect of the present invention, a kind of industrial network terminal is provided, has comprised: CPU; Communication unit is used for the data between the long-range host computer of transmission terminal and industrial network; And first buffer circuit, be arranged between CPU and the communication unit, be used to isolate the electric signal between CPU and the communication unit.
Further; First buffer circuit comprises the first separaant circuit and the second separaant circuit; Communication unit comprises first communication interface and second communication interface, wherein, and the first separaant circuit; Be arranged between first communication interface and the CPU, be used to isolate the electric signal between first communication interface and the CPU; The second separaant circuit is arranged between second communication interface and the CPU, is used to isolate the electric signal between second communication interface and the CPU.
Further, also comprise: power supply unit; And second buffer circuit, be arranged between the power supply unit and second communication interface, be used for the voltage isolation of power supply unit is converted into the supply power voltage of second communication interface.
Further, the first separaant circuit is a network transformer, and the second separaant circuit is the light-coupled isolation chip, and second buffer circuit is the dc-isolation change-over circuit.
Further, first communication interface is an Ethernet interface, and second communication interface is a serial ports.
Further, also comprise: slot; And expanding element, be arranged in the slot, and be connected with CPU via slot, be used to receive the control command that CPU issues and the input signal of processing terminal.
Further, also comprise: input module is used for the input signal of acquisition terminal; Output module is used to export the output signal that expanding element produces; The 3rd buffer circuit is arranged between input module and the expanding element, is used to isolate the electric signal between input module and the expanding element, and the 3rd buffer circuit is the light-coupled isolation chip; The 4th buffer circuit is arranged between output module and the expanding element, is used to isolate the electric signal between output module and the expanding element, and the 4th buffer circuit is the light-coupled isolation chip.
Further; Input module comprises analog quantity input module and digital quantity input module; Wherein, analog quantity input module and digital quantity input module independently are provided with, and the input signal at per four tunnel terminals in the digital quantity input module is one group and inserts expanding element via the light-coupled isolation chip.
Further, also comprise: the 5th buffer circuit, be arranged between power supply unit and the input module, be used for the voltage isolation of power supply unit is converted into the supply power voltage of input module, the 5th buffer circuit is the dc-isolation modular converter.
Further, also comprise: modular converter, be arranged between the 5th buffer circuit and the 3rd buffer circuit, be used for the supply power voltage of input module is converted into the supply power voltage of the 3rd buffer circuit.
Further, also comprise: display unit is used for the operating state of display terminal.
Via the present invention, adopt a kind of comprising: CPU; Communication unit is used for the data between the long-range host computer of transmission terminal and industrial network; And first buffer circuit, be arranged at the industrial network terminal between CPU and the communication unit, be used to isolate the electric signal between said CPU and the said communication unit.The present invention isolates the electric signal between CPU and the communication unit through adopting first buffer circuit, has solved RTU communication interface communication situation problem of unstable in the correlation technique, and then has reached the effect that improves RTU communication interface communication robust property.
Description of drawings
The accompanying drawing that constitutes the application's a part is used to provide further understanding of the present invention, and illustrative examples of the present invention and explanation thereof are used to explain the present invention, do not constitute improper qualification of the present invention.In the accompanying drawings:
Fig. 1 is the industrial network terminal structure sketch map according to the embodiment of the invention;
Fig. 2 is the industrial network terminal structure sketch map according to first embodiment of the invention;
Fig. 3 is the industrial network terminal structure sketch map according to second embodiment of the invention;
Fig. 4 is the industrial network terminal structure sketch map according to third embodiment of the invention;
Fig. 5 is the industrial network terminal power supply sketch map according to the embodiment of the invention;
Fig. 6 is the communication interface electrical isolation sketch map according to first embodiment of the invention;
Fig. 7 is the communication interface electrical isolation sketch map according to second embodiment of the invention;
Fig. 8 is the input module electrical isolation sketch map according to first embodiment of the invention;
Fig. 9 is the input module electrical isolation sketch map according to second embodiment of the invention; And
Figure 10 is the output module electrical isolation sketch map according to the embodiment of the invention.
Embodiment
Need to prove that under the situation of not conflicting, embodiment and the characteristic among the embodiment among the application can make up each other.Below with reference to accompanying drawing and combine embodiment to specify the present invention.
Fig. 1 is the industrial network terminal structure sketch map according to the embodiment of the invention, and is as shown in Figure 1:
In the present embodiment, the first separaant circuit 142 is arranged between first communication interface 162 and the CPU 12, is used to isolate the electric signal between first communication interface 162 and the CPU 12; The second separaant circuit 144 is arranged between second communication interface 164 and the CPU 12, is used to isolate the electric signal between second communication interface 164 and the CPU 12.Through being employed in the first separaant circuit 142 and the second separaant circuit 144 are set respectively between the CPU 12 and first communication interface 162 and second communication interface 164; Realize the electric signal isolation between CPU 12 and the communication interface 16, the terminal called of avoiding electrical Interference to cause is unstable.
Fig. 2 is the industrial network terminal structure sketch map according to first embodiment of the invention, and is as shown in Figure 2:
In the present embodiment; Central processing unit CPU is connected with the I/O processing unit with address bus Address Bus through data/address bus Data Bus; Connect input circuit and output circuit around the I/O processing unit, be respectively applied for the input signal of gathering the industrial network terminal and the output signal of exporting the generation of I/O processing unit; Simultaneously; Central processing unit CPU is connected with programmable device, system program memory, system data storage respectively; To carry out the data interaction of Ethernet interface and serial line interface; Data interaction between the I/O card expanding element, and the data interaction between each storage chip between the network terminal system inside.
Can adopt first communication interface and second communication interface to be the structure of serial ports in the present embodiment, also can adopt first communication interface and second communication interface to be the structure of Ethernet interface; Preferably, first communication interface is an Ethernet interface, and second communication interface is a serial ports; The simple serial communication of the many employings of RTU communication in the correlation technique, second communication interface is a serial ports in the present embodiment, it is mutual that convenient and relevant device of the prior art carries out compatibility; Because there is the problem that communication distance is nearer and communication speed is low in serial communication; First communication interface is an Ethernet interface in the present embodiment; Because Ethernet has characteristics such as cheap, reliable and stable, that communication speed is high, be widely used; The present invention can realize increasing communication distance through Ethernet interface, improves the effect of communication speed.
Have two 10M/100M Ethernet interfaces in the present embodiment, support standard MODBUS ICP/IP protocol, possess dual serial communication interface RS485 or RS232 simultaneously, support standard MODBUS rtu protocol.Can in control system, realize the communication redundancy feature, guarantee data transmission safety, can in communication system, communicate simultaneously again with station, the upper reaches and downstream stations.
Fig. 3 is the industrial network terminal structure sketch map according to second embodiment of the invention, and is as shown in Figure 3:
The embodiment of the invention adopts the I/O fastener to insert the formula structure; I/O fastener expanding element and central processing unit CPU all are arranged in the slot; And, be used to receive the control command that CPU issues and the input signal of processing terminal through being arranged at data/address bus Data Bus and address bus Address Bus on the draw-in groove communication that connects.Therefore for different industrial applications, be with good expansibility.Every suit controller is by a base plate, and a CPU card and some I/O fastener expanding elements are formed.The quantity of I/O fastener expanding element is by the I/O of the The field decision of counting, but the user can carry out the number of flexible configuration expansion I/O slot according to concrete condition.The master control core of industrial network terminal control unit adopts the high-performance RISC CPU dsPIC30F4013 of the U.S. little core company, the crystal oscillator 11MHz of system, and cpu frequency 44MHz, highest running speed can reach 30MIPS.Have 24 bit wide instructions buses and 16 bit wide data/address buss, the flash memory program space on the sheet of 48KB, the RAM of 2KB and the EEPROM of 1KB.And have abundant Peripheral Interface, 5 16 bit timing devices are arranged, catch input for 4 16; 4 16 bit comparisons/PWM outputs; 3 line SPI (Serial Peripheral Interface is called for short SPI) Serial Peripheral Interface (SPI) module, and IIC and CAN bus module; And inner integrated DSP engine, very fast to complex mathematical calculation process speed.
Fig. 4 is the industrial network terminal structure sketch map according to third embodiment of the invention, and is as shown in Figure 4:
Adopt many CPU collaborative work formula structure in the embodiment of the invention, wherein the processor on the core CPU integrated circuit board mainly be responsible for the peripheral hardware communication interface data interaction (this comprises 2 Ethernet interfaces and 2 RS-232 or RS-485 serial line interface) and and the communication of internal system various piece (this comprise and the I/O card between data interaction and each storage chip of internal system, the data interaction between the data storage register).The I/O signal type that CPU on the I/O card is corresponding different is handled corresponding data, accomplishes the inspection and the collecting work of signal.
The core of native system is the dsPIC30F4013 single-chip microcomputer on the CPU card; It is not only bearing the data interaction that connects the peripheral hardware communication interface; But also the signal that detects on the I/O fastener expanding element and collect is focused on; And can pass through long-range host computer, and various control commands are issued on each I/O fastener expanding element, on-the-spot various device is taked corresponding action.
Be collection remote data acquisition, metering and the RTU remote terminal controller that is controlled in one automatically in the embodiment of the invention,, can gather and export dissimilar signals for different I/O fasteners.The standard 4-20mA signal of analog quantity input AI module ability collection site instrument and meter; Digital quantity input DI module provides the switch data acquisition channel, and input signal types is the dry contact input; Analog quantity output AO module has two kinds of selectable output signal types, is respectively 4-20mA or 1-5V signal; Digital quantity output DO module provides the switch data output channel, and the output signal type is dry contact output, and output of optional normally opened contact or normally-closed contact output dual mode.According to the The field needs, the user can be configured different I/O fastener expanding element combinations flexibly, to meet the different needs.
The communications portion of the embodiment of the invention is mainly by spi bus, UART serial line interface, CAN Bus bus, the address bus Address Bus of iic bus and chip chamber and data/address bus Data Bus.
The spi bus system is a kind of synchronous serial Peripheral Interface, and it can make MCU and various ancillary equipment communicate with exchange message with serial mode.The periphery is provided with FLASHRAM, network controller, LCD display driver, A/D converter and MCU etc.The spi bus system can be directly and the multiple standards peripheral components direct interface of each manufacturer production, and this interface is general to use 4 lines: serial time clock line SCK, main frame input/slave output data line MISO, main frame output/slave input data line MOSI and the effective slave selection wire/CS of low level.Compatible IEEE 802.3 standards of the network control core ENC28J60 of the U.S. that we select for use little core company, integrated MAC and 10base-T PHY, the 10base-T port that the tenaculum auto polarity detects and proofreaies and correct is supported the full and half duplex pattern.ENC28J60 is the whole world ethernet controller of minimum encapsulation at present; Before this; Embedded design personnel use that optional ethernet controller all aims at personal computing system's design when inserting providing for Long-distance Control or monitoring, and are not only complicated, but also take up space, and relatively more expensive.The encapsulation that most of in the market ethernet controller adopts is all above 80 pins, and the ENC28J60 that meets IEEE 802.3 agreements has only 28 pins, and function corresponding just can both be provided, and can simplify relevant design again greatly, and reduce to account for board space.In addition, the ENC28J60 ethernet controller adopts the SPI serial line interface (maximum speed can reach 10Mb/s) of industrywide standard, only needs 4 lines to be connected with main control singlechip.These functions add the ICP/IP protocol stack that is provided free by Microchip, be used for single-chip microcomputer, make it to become minimum on the market at present Embedded Application Ethernet solution.And than the Ethernet chip RTL8019AS that used mostly in the past; ENC28J60 uses serial SPI interface and CPU to carry out communication; It is few to take the I/O mouth, is the parallel bus interface that data wire adds address wire and nearly the RTL8019AS of 100 pins uses, and the I/O mouth that takies CPU is more.Native system possesses 2 independently 10M/100M Ethernet RJ45 interfaces, and the ethernet control chip of employing is the ENC28J60 that the U.S. little core company produces.Native system is interface with the spi bus through CPU; Two Ethernet control of poll ENC28J60; Thereby expand two ethernet communication interfaces, make that like this resource use distribution is reasonable more and satisfied more communication needs, communications protocol is followed standard Modbus TCP/IP.
Integrated two the UART serial line interfaces of core CPU expand two DB9 pin RS-232 or RS-485 serial ports of following standard ModBus rtu protocol, and baud rate can be provided with from 2400bps to 115200bps, can satisfy the communication need of field instrumentation instrument and controller.
Utilize the RS-485 interface can articulate more slave unit, constitute the primary and secondary structure system with bus mode, communication mode carries out with the mode of main website poll.General maximum 32 nodes of supporting of RS-485 bus if use 485 special chips, can reach 128 or 256 nodes, and maximum can support 400 nodes.Because of the RS-485 interface has good noise immunity, above-mentioned advantages such as long transmission range and multistation ability just make it become first-selected serial line interface.Because the half-duplex network that the RS485 interface is formed, general needs two lines, so the RS485 interface all adopts the Shielded Twisted Pair transmission.
(it is a kind of serial line interface to the inner integrated manipulator local area network (LAN) of core CPU for Controller Area Network, CAN) module, is used for and other CAN module or single chip communication.This interface protocol designs under noise circumstance, communicating.The CAN module is exactly a communication controler, has realized the CAN 2.0A or the CAN 2.0B agreement that define in the BOSCH standard.This module is also supported CAN 1.2, CAN 2.0A, CAN 2.0B Passive and CAN 2.0B Active version, has realized a kind of complete CAN system.Through the CAN bus, the CPU card is set up data communication with each I/O card that expands.
CPU has 24 bit wide instructions buses and 16 bit wide data/address buss, thereby can accomplish the data and the instruction interaction of internal system through inner data and address bus.
Fig. 5 is the industrial network terminal power supply sketch map according to the embodiment of the invention, and is as shown in Figure 5:
The application's power unit is divided into two parts again, is respectively the power supply on the CPU card, the power supply on the I/O fastener expanding element.The whole system power supply is the 24V direct current, and the voltage width that can bear is 12V to 40V.After on-the-spot power supply caused internal system, power supply was divided into 24V, 5V, 3.3V.Wherein 24V gives the power supply of I/O fastener expanding element through system backplane, and 5V is the operating voltage of CPU, and 3.3V is the operating voltage of ethernet control chip.On this external CPU card; To the second communication interface serial ports part; With the second buffer circuit 24VDC-5VDC isolation module (isolation voltage >=1000V DC); System's 24V isolated from power is converted into 5V, and systematically separates, can prevent the damage that control appliance is caused from the surge impact of scene through serial ports like this.Through the power supply of controller internal power supply and communication interface is isolated; Both power supplys have been carried out electrical isolation with reference to ground, even smashed to reach communication interface, but the effect that the controller remainder still can operate as normal.
Fig. 6 is the communication interface electrical isolation sketch map according to first embodiment of the invention, and is as shown in Figure 6:
Ethernet interface in the embodiment of the invention adopts the RJ45 Ethernet interface; Its inside is connected with CPU through network transformer, if do not add isolation, though also can operate as normal; But transmission range is just very restricted; And when receiving the varying level network interface, also can be influential, and outside also very big to the interference of chip.After having connect network transformer, it is mainly used in the signal level coupling.One of which can enhancing signal, makes its transmission range farther; Its two, make die terminals and external isolation, antijamming capability strengthens greatly, and chip has been increased very big protective effect (as thunderbolt); Its three, when receive varying level (if any the PHY chip be 2.5V, the PHY chip that has is 3.3V) network interface the time, can not impact equipment each other.In concrete communication link; The node reference of two different locations " " current potential maybe be different, if do not isolate, incoming level can surpass the tolerance limit of interface circuit; Gently then signal can not correctly be discerned and cause and make mistakes or temporary transient actual effect, and is heavy then cause expendable physical damage.
Wherein, interface side externally, pin J1 (TD+) and pin J2 (TD-) are used for data and send; Pin J3 (RX+) and pin J6 (RX-) are used for Data Receiving; Pin J4, pin J5, pin J7 and pin J8 are unsettled.In chip side, pin P1 (TD+) and pin P2 (TD-) are used for data and send; Pin P7 (RX+) and pin P8 (RX-) are used for Data Receiving; Pin P3, pin P4 and pin P6 are unsettled, and pin P5 connects with reference to ground; Pin P9 is the anode of green LED lamp, and pin P10 is the negative electrode of green LED lamp, and pin P11 is the negative electrode of yellow LED lamp, and house keeper P12 is the anode of yellow LED lamp.And, in the circuit of chip side and external interface side, be connected with the resistance of 4 75 ohm (4 * 75 ohm), the electric capacity of the network transformer of 1CT:1CT (Center Tap is called for short CT) and 1000PF, 2KV.
Fig. 7 is the communication interface electrical isolation sketch map according to second embodiment of the invention, and is as shown in the figure:
Peripheral hardware serial equipment in the embodiment of the invention is connected with the MAX232EPE chip; And through light-coupled isolation chip and inner UART (the Universal Asynchronous Receiver/Transmitter of industrial network terminal system; Abbreviation UART) the U1TX end of universal asynchronous reception/transmission interface is connected with the U1RX end; Native system inside has 2 UART interfaces, all is used for the RS232/485 serial communication; Wherein U1TX and U1RX represent the data sending terminal mouth and the Data Receiving port of first via UART interface respectively.
Photoelectricity is isolated and is also claimed that optical coupling, optical coupling are the media transmission signal of telecommunication with light, and it has the good isolation effect to input, the output signal of telecommunication.So it is widely used in various circuit.Optical coupler generally is made up of three parts: the emission of light, the reception of light and signal amplify.The signal of telecommunication driven for emitting lights diode (LED) of input makes it to send the light of certain wavelength, is received and produce photoelectric current by photo-detector, and the triode through the other end further amplifies back output again.This has just accomplished the conversion of electricity-light-electricity, thereby plays the effect of input, output, isolation.Owing to isolate mutually between the optical coupler input and output, signal of telecommunication transmission has characteristics such as one-way, thereby has good electrical isolation capabilities and antijamming capability.The major advantage of optical coupler is: the signal one-way transmission, and input and output have been realized electrical isolation fully, and the output signal does not have influence to input, and antijamming capability is strong, working stability.Photoelectricity is isolated in and plays considerable effect in the serial communication at present; In serial communication; It can greatly protect RS232/485 serial interface equipment, accidental damage and the damage of having avoided earth loop voltage, surge, indirect lightning strike, static, adverse circumstances such as hot-swappable that RS232/485 equipment is caused.Disturb because in the industry spot environment, run into signal ground through regular meeting, power supply disturbs, and space electric field disturbs, and the interference of other high order harmonic component etc. all can have influence on the safety of the stable and equipment of communication.Isolation is the introducing in order to prevent to disturb; In long line communication, tend to induce tangible interference signal on the circuit; And also possibly exist between communication two party such as ground reference difference, system noise and tolerance difference or the like, these factors that influence system will be tackled firmly significantly after isolating, otherwise not only can have influence on the accuracy of communication data; Even maybe be because of the huge drop of two ends reference potential, control appliance etc. is burnt in the loop that impacts.
The communication interface of whole system comprises that two Ethernet interfaces and two serial ports have all realized electrical isolation in the embodiment of the invention, the safety and stability that can well protect controller like this and guarantee communication.
Fig. 8 is the input module electrical isolation sketch map according to first embodiment of the invention, and is as shown in Figure 8:
Analog quantity input AI module is passed through wire jumper, the external two-wire system of industrial network terminal control unit ability, and three-wire system or four-wire system instrument receive signal and should be standard 4---the 20mA electric current.In the two-wire system transmission means, power supply, load resistance, transmitter are connected, and promptly two leads transmit required power supply of transmitter and output current signal simultaneously; In the three-wire system mode, the anode of power positive end and signal output, their shared ground wires, its current signal obtains between I+ and V-two ends.In the four-wire system mode, power supply, load resistance are to link to each other with transmitter respectively, i.e. power supply and transmitter output signal is respectively with two lead transmission.Because native system has carried out electric isolation fully to the AI passage, therefore can shield disturbing factor to a great extent from the scene.
The optocoupler that in the collection of simulant signal passage, adopts Agilent company to produce in this instance amplifies chip HCPL-7840; This chip can suppress the common mode disturbances of 15kV/us; Input off-set voltage is controlled in the 0.3mV; 0.004% nonlinear distortion, 0.8 micron CMOS IC design technology and 8 pin dip.Design circuit is that difference inputed to light-coupled isolation chip HCPL-7840 after the 4-20mA current signal of field instrument input became voltage signal through accurate sampling resistor; And the light-coupled isolation chip carries specified 8 times of gain amplifiers; Difference exports high accuracy track to track operational amplifier to and amplifies after amplifying, and exports CPU at last to and carries out sample detecting.Adopting the advantage of differential amplifier circuit obvious, mainly be that antijamming capability is strong, and the interference signal major part all is a common-mode signal.The input of this circuit is the input of two signals, and the difference of these two signals is the effective input signal of circuit, and the output of circuit is the amplification to the difference of these two input signals.Imagine a kind of like this sight,, can produce identical interference two input signals if there is interference signal, poor through the two, interference signal effectively be input as zero, this has just reached the purpose of anti-common mode disturbances.
Fig. 9 is the input module electrical isolation sketch map according to second embodiment of the invention, and is as shown in Figure 9:
For digital quantity amount input DI module, system accepts the dry contact signal.Equally; In order to prevent that on-the-spot interference and electric pulse from hitting signal and equipment are caused expendable injury; We have done electrical isolation to the DI signalling channel, promptly each road DI signal all just inputs to control system after isolating, and are mutual electrical isolation between per 4 the tunnel.The DI signal of design field instrument input is after opto-coupler chip TP521 isolates, and transmission DI signal is to CPU.Realization supervision and control need be used various instrument and meter for automations, control system and actuator in industrial processes; Signal between them transmits existing faint small-signal to millivolt level, milliampere level; There are tens volts again, even thousands of volt, hundreds of amperes large-signal; Existing low frequency direct current signal also has high-frequency pulse signal or the like, often finds behind the construction system that the signal transmission interferes with each other between instrument and equipment, causes system's instability even misoperation.This situation appears except the performance reason such as anti-electromagnetic interference effect of each instrument, equipment itself; Also have a crucial reason to be owing to have electrical potential difference between the signal reference point between instrument and the equipment, thereby formation " ground loop " cause the even not reversible device damage of distortion in the signals transmission.Therefore, guarantee system stability and operation reliably." ground loop " problem is the problem that in the system signal processing procedure, must solve.And a simple solution of expecting easily is to make the electromotive force of two earth points identical (making Vgnd1=Vgnd2), but owing to receive the influence of numerous factors such as geological conditions and climate change between the earth point, this scheme can't can be accomplished in reality in fact fully.Therefore for the switching value signals collecting at scene, we have accomplished that per 4 the tunnel one groups are isolated, and reason is that a kind of switching signal of the transmission of on-the-spot most of instrument and meter equipment is often represented by several DI signals jointly, and therefore to do one group of isolation more reasonable for 4 road DI.Through in each process loop, using signal isolation method, break off the process loop like this, the normal transmission of influence process signal not again simultaneously, thereby thoroughly solve ground loop issues, guarantee stablizing of signal transmission errorless with safety control appliance.
The 3rd buffer circuit is two parts in this instance; Be respectively analog quantity input isolation circuit (AI) and the switching value input isolation circuit (DI) in the input module; Input port and on-site signal through with controller carry out electrical isolation, have reached the effect of protection controller equiment.On the I/O card, on-the-spot AI signal and the DI signal of gathering carried out comprehensive electrical isolation, the reason of doing like this is: 1. in signals transmission, realize the electrical isolation of primary side and secondary side, solve anti-interference problem; 2. cut-out primary side and secondary side earth potential do not wait at earth point and cause the influence of circulation to analog signals.Suppose not take quarantine measures; Even the floating empty or single-point grounding of system; Because signalling channel between the secondary device that number acid, alkaline tide wet situation cause and screen also can produce circulation to not leaking electricity to equipotential and be added on the transmission line analog signal; Influence the accuracy of measuring-signal, even measure inefficacy.3. the common-mode voltage over the ground and the surge of energy are arranged, protection double sampling equipment on the isolation signals transmission line.The electric circumstance of industry spot is very complicated; The analog signals line in transmission course because the influence of factors such as peripheral equipment, power cable passage, transformation process, device fabrication, construction quality; Signal transmssion line often brings the common mode disturbance voltage that continues up to holding more than the hectovolt, and double sampling equipment can be directly burnt in this interference.
Adopt fastener expansion slot formula structure in the present embodiment, flexible configuration.Possesses the Dual-Ethernet mouth in the communication; The rapidity and the real-time of transfer of data have been guaranteed; Can realize data remote through network equipments such as routers; Satisfy real-time collection and the monitoring of upper station control, also possess 2 road RS-232/RS-485 serial communication interfaces simultaneously, satisfy different communication interface demands field data.And all accomplished the electrical isolation completely of communication interface circuit, guaranteed that the communication data transmission safety is accurate.
On I/O fastener expanding element, make the electrical isolation of AI signal and DI signalling channel, and interchannel is each other fully independent, make the configuration of construction system, regular maintenance convenient.Guaranteeing more effectively to suppress on-the-spot various disturbing factors on the integrality of signal transmission loop, the normal transmission of influence process signal not again simultaneously, thus thoroughly guaranteed the accurate transmission of signal and the safety of each equipment.
In addition; No matter be signals collecting and the output point on communication interface or the I/O card; The industrial network terminal control unit all has corresponding state LED lamp to indicate current data transmit-receive and signal input/output state, and this diagnosis for plant maintenance and abnormal signal has suitable help.
Figure 10 is the output module electrical isolation sketch map according to the embodiment of the invention, and is shown in figure 10:
In analog quantity output AO module; Use beautiful high accuracy 12 Bits Serial DAC (the Digital-Analog Converter that believe semiconductor company in the present embodiment; Abbreviation DAC) digital to analog converter chip MAX531 carries out the analog output interface circuit circuit design, adopts spi bus to carry out communication between this D/A chip and the main control chip dsPIC30F4013.In order to adapt to complicated harsh industry spot environment, we have carried out comprehensive electrical isolation design to the circuit of analog quantity output equally.Its method is between main control chip dsPIC30F4013 and DAC chip MAX531, to carry out opto-electronic conversion through 4 light-coupled isolation chip TLP521 to isolate; Particularly; Light-coupled isolation chip 1 first input end connects main device data output, from device data input signal SDI, second input connects supply voltage through R1 resistance; Light-coupled isolation chip 2 first input ends connect from the device reset signal
that resets, and second input connects supply voltage through R3 resistance; Light-coupled isolation chip 3 first input ends meet clock signal SCLK, and second input connects supply voltage through R5 resistance; Light-coupled isolation chip 4 first input ends connect from device enable signal
, and second input connects supply voltage through R7 resistance; The equal ground connection of first output of 4 light-coupled isolation chips, second output connects supply voltage through pull-up resistor R2, R4, R6 and R8 respectively, and wherein, the resistance size of R1 to R8 is 300 ohm.Isolate conversion through photoelectricity, thereby internal system is played a good protection.Output at DAC chip MAX531 just can export 1---and the 5V voltage signal, carry out simple voltage electricity through 250 ohm of precision resistances again and stay conversion, also exportable 4---the 20mA current signal.
Digital quantity output DO module can be exported optional often opening or normally closed dry contact signal.CPU is output corresponding digital amount signal earlier, at a distance from chip, drives relay through light, exports corresponding dry contact signal at last.The output capacity of relay is voltage 24V, electric current 2A.
Through the embodiment of the invention, the output module interface and the on-site signal of controller carried out electrical isolation through the light-coupled isolation chip, realized the effect of protection controller equiment.
From above description, can find out that the present invention is through adopting a kind of comprising: CPU; Communication unit is used for the data between the long-range host computer of transmission terminal and industrial network; And first buffer circuit, be arranged at the industrial network terminal between CPU and the communication unit, be used to isolate the electric signal between said CPU and the said communication unit.The present invention isolates the electric signal between CPU and the communication unit through adopting first buffer circuit, has solved RTU communication interface communication situation problem of unstable in the correlation technique, and then has reached the effect that improves RTU communication interface communication robust property.
Obviously, it is apparent to those skilled in the art that above-mentioned each module of the present invention or each step can realize with the general calculation device; They can concentrate on the single calculation element; Perhaps be distributed on the network that a plurality of calculation element forms, alternatively, they can be realized with the executable program code of calculation element; Thereby; Can they be stored in the storage device and carry out, perhaps they are made into each integrated circuit modules respectively, perhaps a plurality of modules in them or step are made into the single integrated circuit module and realize by calculation element.Like this, the present invention is not restricted to any specific hardware and software combination.
The above is merely the preferred embodiments of the present invention, is not limited to the present invention, and for a person skilled in the art, the present invention can have various changes and variation.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.
Claims (10)
1. an industrial network terminal is characterized in that, comprising:
CPU;
Communication unit is used to transmit the data between said terminal and the long-range host computer of industrial network; And
First buffer circuit is arranged between said CPU and the said communication unit, is used to isolate the electric signal between said CPU and the said communication unit.
2. industrial network according to claim 1 terminal is characterized in that, said first buffer circuit comprises the first separaant circuit and the second separaant circuit, and said communication unit comprises first communication interface and second communication interface, wherein,
The said first separaant circuit is arranged between said first communication interface and the said CPU, is used to isolate the electric signal between said first communication interface and the said CPU;
The said second separaant circuit is arranged between said second communication interface and the said CPU, is used to isolate the electric signal between said second communication interface and the said CPU.
3. industrial network according to claim 2 terminal is characterized in that, also comprises:
Power supply unit; And
Second buffer circuit is arranged between said power supply unit and said second communication interface, is used for the voltage isolation of said power supply unit is converted into the supply power voltage of said second communication interface.
4. industrial network according to claim 2 terminal is characterized in that, the said first separaant circuit is a network transformer, and the said second separaant circuit is the light-coupled isolation chip, and said second buffer circuit is the dc-isolation change-over circuit.
5. industrial network according to claim 2 terminal is characterized in that, said first communication interface is an Ethernet interface, and said second communication interface is a serial ports.
6. industrial network according to claim 1 terminal is characterized in that, also comprises:
Slot; And
Expanding element is arranged in the said slot, and is connected with said CPU via said slot, is used to receive control command that said CPU issues and the input signal of handling said terminal.
7. industrial network according to claim 6 terminal is characterized in that, also comprises:
Input module is used to gather the input signal at said terminal;
Output module is used to export the output signal that said expanding element produces;
The 3rd buffer circuit is arranged between said input module and the said expanding element, is used to isolate the electric signal between said input module and the said expanding element, and said the 3rd buffer circuit is the light-coupled isolation chip;
The 4th buffer circuit is arranged between said output module and the said expanding element, is used to isolate the electric signal between said output module and the said expanding element, and said the 4th buffer circuit is the light-coupled isolation chip.
8. industrial network according to claim 7 terminal; It is characterized in that; Said input module comprises analog quantity input module and digital quantity input module; Wherein, said analog quantity input module and said digital quantity input module independently are provided with, and the input signal at per four tunnel said terminals in the said digital quantity input module is one group and inserts said expanding element via said light-coupled isolation chip.
9. industrial network according to claim 7 terminal is characterized in that, also comprises:
The 5th buffer circuit is arranged between said power supply unit and the said input module, is used for the voltage isolation of said power supply unit is converted into the supply power voltage of said input module, and said the 5th buffer circuit is the dc-isolation modular converter.
10. industrial network according to claim 9 terminal is characterized in that, also comprises:
Modular converter is arranged between said the 5th buffer circuit and said the 3rd buffer circuit, is used for the supply power voltage of said input module is converted into the supply power voltage of said the 3rd buffer circuit.
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| CN2011103383609A CN102510352A (en) | 2011-10-31 | 2011-10-31 | Industrial network terminal |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2011103383609A CN102510352A (en) | 2011-10-31 | 2011-10-31 | Industrial network terminal |
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| CN102867398A (en) * | 2012-09-21 | 2013-01-09 | 济钢集团有限公司 | Data collection module |
| CN102957569A (en) * | 2012-11-21 | 2013-03-06 | 航天科工深圳（集团）有限公司 | Link maintenance method and device for distribution network failure positioning system |
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| CN102808662A (en) * | 2012-07-30 | 2012-12-05 | 江苏永钢集团有限公司 | Anti-interference device of expansion machine |
| CN103595693A (en) * | 2012-08-14 | 2014-02-19 | 成都思迈科技发展有限责任公司 | An RS-485 converting-to-Ethernet protocol converter based on a half-duplex working mode |
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| CN102957569A (en) * | 2012-11-21 | 2013-03-06 | 航天科工深圳（集团）有限公司 | Link maintenance method and device for distribution network failure positioning system |
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| CN103000020A (en) * | 2012-12-24 | 2013-03-27 | 北京唯绿建筑节能科技有限公司 | Multi-parameter data collector |
| CN103067236A (en) * | 2012-12-24 | 2013-04-24 | 北京唯绿建筑节能科技有限公司 | Data acquisition device with composite transmission mode |
| CN103218334A (en) * | 2013-03-30 | 2013-07-24 | 西北工业大学 | Computer peripheral cascade device based on USB (Universal Serial Bus) and RS485 bus |
| CN103321665A (en) * | 2013-07-18 | 2013-09-25 | 天津华宁电子有限公司 | Support controller for electrohydraulic control system |
| CN103321665B (en) * | 2013-07-18 | 2015-07-22 | 天津华宁电子有限公司 | Support controller for electrohydraulic control system |
| CN103903412B (en) * | 2014-03-28 | 2017-04-12 | 哈尔滨工程大学 | CAN (Controller Area Network) bus to 4-20mA data signal conversion device for NOx sensor |
| CN104806496A (en) * | 2015-03-04 | 2015-07-29 | 上海发电设备成套设计研究院 | Time statistics and setting based pump group liquid level control system and method |
| CN106898131A (en) * | 2015-12-17 | 2017-06-27 | 广州航天海特系统工程有限公司 | A kind of single fiber data transmission system |
| CN107317735B (en) * | 2017-06-29 | 2023-03-24 | 北京广利核系统工程有限公司 | Network topology device and method for control station and instrument control system |
| CN107317735A (en) * | 2017-06-29 | 2017-11-03 | 北京广利核系统工程有限公司 | Control station network topology device, method and I＆C system |
| CN107819659A (en) * | 2017-10-24 | 2018-03-20 | 七玄驹智能科技（上海）有限公司 | A kind of intelligent level UNICOM communication network based on SPI |
| CN107819659B (en) * | 2017-10-24 | 2020-09-29 | 七玄驹智能科技（上海）有限公司 | Intelligent cascade communication network based on SPI |
| WO2020020079A1 (en) * | 2018-07-27 | 2020-01-30 | 北京兴达智联科技有限公司 | Serial communication method and system for operation of multiple groups in high voltage environment |
| CN109086239B (en) * | 2018-07-27 | 2021-10-19 | 北京兴达智联科技有限公司 | Multi-group running serial communication method and system in high-voltage environment |
| CN109086239A (en) * | 2018-07-27 | 2018-12-25 | 段志刚 | The serial communication method and system of multiple groups operation in a kind of high voltage environment |
| CN115174655A (en) * | 2022-08-23 | 2022-10-11 | 东方合智数据科技(广东)有限责任公司 | Method and system for accessing equipment in corrugated paper packaging industry to cloud platform |
| CN115174655B (en) * | 2022-08-23 | 2023-06-23 | 东方合智数据科技(广东)有限责任公司 | Method and system for accessing equipment in corrugated paper packaging industry to cloud platform |
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Application publication date: 20120620 |