CN113839903A - Protocol conversion device based on HART technology - Google Patents
Protocol conversion device based on HART technology Download PDFInfo
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- CN113839903A CN113839903A CN202010512138.5A CN202010512138A CN113839903A CN 113839903 A CN113839903 A CN 113839903A CN 202010512138 A CN202010512138 A CN 202010512138A CN 113839903 A CN113839903 A CN 113839903A
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- H—ELECTRICITY
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- H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
- H04L69/08—Protocols for interworking; Protocol conversion
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Abstract
The invention provides a protocol conversion device based on HART technology, which comprises a measurement and control device and a plurality of RS485 and HART conversion circuits connected with the measurement and control device; each RS485 and HART conversion circuit comprises a power management module, an RS485 signal conversion module, a data analysis module, a HART communication module and a HART instrument; the RS485 signal conversion module, the data analysis module, the HART communication module and the HART instrument are sequentially connected; the power management module provides power for each RS485 and HART conversion circuit. The invention realizes the data bidirectional communication between instruments with two different interfaces of HART and RS485 and communication protocols, so that instruments with different brands and different protocols on the industrial site form a sensor measurement and control network.
Description
Technical Field
The invention belongs to the technical field of automatic instrument measurement and control, and particularly relates to a protocol conversion device of an HART interface and an RS485 interface.
Background
Hart (highway Addressable Remote transmitter) is a highway Addressable Remote sensor data path used for data transmission protocols between intelligent meters and control systems. According to the method, FSK (frequency shift keying) digital signals are superposed on analog signals, so that the industrial standard of 4-20 mA analog signals is kept, and the function of transmitting process and transmitter data in a digital form is realized. The disadvantages are that the transmission speed is slow, and the number of bus networking nodes is small.
RS485 communication adopts a half-duplex working mode and supports multipoint data communication. The balanced transmission and differential reception are adopted, so that the transmission speed is high, and the capability of inhibiting common-mode interference is realized. RS485 is applied to remote data bidirectional communication between embedded instruments and meters in industrial environment, and is characterized by high transmission rate, low error rate and high bus networking node number.
In the prior art, HART and RS485 need to realize the communication function through the gateway board card connected with a computer and the computer programming, so that the industrial field is inconvenient to expand, the expansion space is limited, the purchase cost is high, and the large-scale use is not facilitated.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a protocol conversion device based on HART technology. The scheme of the invention can solve the problems in the prior art.
The technical solution of the invention is as follows:
a protocol conversion device based on HART technology comprises a measurement and control device and a plurality of RS485 and HART conversion circuits connected with the measurement and control device;
each RS485 and HART conversion circuit comprises a power management module, an RS485 signal conversion module, a data analysis module, a HART communication module and a HART instrument;
the RS485 signal conversion module, the data analysis module, the HART communication module and the HART instrument are sequentially connected;
the power management module provides power for each RS485 and HART conversion circuit;
the RS485 signal conversion module converts the received RS485 format signal and UART serial port data into each other;
the data analysis module analyzes the received UART serial port data according to a protocol;
the HART communication module converts the received UART serial port data and HART format signals mutually;
the signal transmission path from RS485 to HART is as follows:
the RS485 signal conversion module receives an RS485 format signal sent by the test equipment, converts the RS485 format signal into UART serial port data and transmits the UART serial port data to the data analysis module;
the data analysis module analyzes the received UART serial port data according to a protocol and then transmits the data to the HART communication module;
the HART communication module converts the acquired analysis data into HART format signals and transmits the HART format signals to a HART instrument;
otherwise, the HART to RS485 signaling can be accomplished in the reverse path.
Furthermore, the number of RS485 and HART conversion circuits connected with the measurement and control equipment is at most 320.
Furthermore, the data analysis module comprises a single chip microcomputer and a crystal oscillator circuit, the crystal oscillator circuit generates a qualified clock signal for the single chip microcomputer, the single chip microcomputer receives UART serial port data of the RS485 signal conversion module, carries out frame format conversion and then sends the data to the HART communication module, and the single chip microcomputer receives the UART serial port data of the HART communication module, carries out frame format conversion and then sends the data to the RS485 signal conversion module.
The single chip microcomputer meets the following requirements: 48MIPS, 4352B RAM, 64K FLASH, can be programmed in a system, 2 enhanced UART serial ports, 4 universal 16-bit counters/timers and 40I/O ports, the device has a power-on reset function, and the crystal oscillator circuit meets the serial port standard.
Furthermore, the HART communication module comprises a HART modem chip, a rail-to-rail amplifier chip and a CMOS analog switch.
Furthermore, the CMOS analog switch adopts a single-pole single-throw analog switch, has rail-to-rail output capability, is compatible with TTL/CMOS logic, and realizes the self-adaptive switching of HART modes of different wire systems.
Compared with the prior art, the invention has the beneficial effects that:
(1) according to the invention, by analyzing and converting the RS485 and HART signals, the data bidirectional communication between instruments and meters with two different interfaces of HART and RS485 and communication protocols is realized;
(2) the invention solves the defects of low transmission rate of HART protocol and small quantity of networking instruments through the RS485 signal conversion module and the data analysis module, can improve the transmission rate to 10Mbps at most by using the RS485 interface, and increases the networking quantity to 320, so that the instruments with different brands and different protocols in the industrial field form a sensor measurement and control network.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
Fig. 1 is a schematic diagram illustrating an implementation of a protocol conversion circuit and a system for a HART interface and 485 interface according to an embodiment of the present invention;
FIG. 2 illustrates a circuit schematic of a power management module provided in accordance with an embodiment of the invention;
fig. 3 shows a schematic circuit diagram of an RS485 signal conversion module provided according to an embodiment of the present invention;
FIG. 4 illustrates a circuit schematic of a data parsing module provided in accordance with an embodiment of the present invention;
fig. 5 is a schematic circuit diagram of a HART communication module according to an embodiment of the present invention.
Detailed Description
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.
The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
As shown in fig. 1, a protocol conversion apparatus based on HART technology according to an embodiment of the present invention includes a measurement and control device and a plurality of RS485 and HART conversion circuits connected thereto;
each RS485 and HART conversion circuit comprises a power management module, an RS485 signal conversion module, a data analysis module, a HART communication module and a HART instrument;
the RS485 signal conversion module, the data analysis module, the HART communication module and the HART instrument are sequentially connected;
in one embodiment, as shown in fig. 2, after the power supply of the 24V power supply passes through a self-recovery fuse F1 and an anti-reverse diode D1, the power supply enters a DC/DC isolation power WRB2405S-1WR2, and after the DC5V is output, the power supply passes through a Low Dropout (LDO) voltage regulator TPS76333DBV and an output DC3.3V for supplying power to the RS485 signal conversion module, the data analysis module and the HART communication module, the circuit is further connected with transient discharge tubes TVS1, TVS2, electrolytic capacitors C1, C2 and C4, so that the functions of overvoltage, overcurrent and anti-reverse voltage access protection are achieved, and meanwhile, the capability of stable 3.3V power supply is provided.
In an embodiment, as shown in fig. 3, RS485 data sent by the measurement and control device enters from an A, B interface, after passing through a high-speed protector TBU1 and TBU2, overvoltage protection is performed on a bus, overcurrent protection is performed on the bus through a parallel transient discharge tube TVS4, driving capability is improved through an up-pull resistor R15 and a down-pull resistor R14, and anti-interference capability is increased, the data is converted into a UART bus format through a chip SN65HVD1780D, and is transferred to a data analysis module through a chip SN65HVD1780D pin 1 and pin 4, and in the process of data return, the data returned by the data analysis module is converted into an RS485 format through the chip SN65HVD17 1780D and is returned to the measurement and control device for networking data exchange;
in one embodiment, as shown in fig. 4, a single chip microcomputer and a crystal oscillator circuit with the model number of C8051F340 are selected, the crystal oscillator circuit generates a qualified clock signal for the single chip microcomputer, the crystal oscillator circuit selects a serial standard 11.0592MHz crystal oscillator, the pin 47 of the single chip microcomputer C8051F340 is connected with the crystal oscillator, the data converted by the RS485 signal conversion module is connected with the pin 3 and the pin 4 of the single chip microcomputer C8051F340 through a UART bus 1, the data is sent to the inside of the single chip microcomputer C8051F340, the data is cached and converted in a data frame format, the pin 1 and the pin 2 of the single chip microcomputer C8051F340 are respectively connected with a HART modem, and the analyzed data is sent to the HART modem;
in a specific embodiment, as shown in fig. 5, the HART communication module includes a low power consumption HART modem chip of YT-HART, a rail-to-rail amplifier chip of AD8541ART, and a CMOS analog switch of MAX4646 EUK-T. The signal output by the data analysis module is transmitted to a low-power consumption HART modem chip YT-HART of a HART communication module through a UART bus 2 according to HART protocol speed, and is converted into an analog signal, a pin 23 of the low-power consumption HART modem chip YT-HART is respectively connected with an AD8541ART pin 3 and a pin 4 of an amplifier chip AD8541ART through resistors RT and R19, after being amplified by 3 times through an AD8541ART of a rail-to-rail amplifier chip, the signal enters through a CMOS analog switch MAX4646EUK-T pin 1, a pin 2 is output and then is sent to a HART instrument, then a signal parameter of the HART instrument is read back to the interior of a singlechip C8051F340 through a pin 18 of the low-power consumption HART modem chip YT-HART, the analog signal is converted into a digital signal through the low-power consumption HART modem chip YT-HART, the digital signal is transmitted back to an RS485 signal conversion module through a UART bus 1, then the network data is transferred back to the measurement and control equipment for networking data exchange. The CMOS analog switch MAX4646EUK-T realizes the self-adaptive switching of a standard two-wire system HART mode and a four-wire system HART mode, and meets the compatibility of a two-wire system HART instrument and a four-wire system HART instrument.
The transmission path of signals from RS485 to HART to each other is:
RS485 data sent by the measurement and control equipment enters from an A, B interface, after passing through a high-speed protector TBU1 and a TBU2, overvoltage protection is performed on the bus, overcurrent protection is performed on the bus through a parallel transient discharge tube TVS4, driving capability is improved through an up-pull resistor R15 and a down-pull resistor R14, anti-interference capability is increased, the data are converted into a UART bus format through a chip SN65HVD17 1780D, the data are connected with a pin 3 and a pin 4 of a singlechip C8051F340 through a UART bus 1, sent into the singlechip C8051F340, and are subjected to cache, a pin 1 and a pin 2 of the singlechip C8051F340 are respectively connected with a pin 8 and a pin 9 of a low-power consumption HART modem chip YT-HART, forwarded to the HART modem chip YT-HART of a HART communication module through a HART bus 2 according to HART protocol rate, digital signals are converted into analog signals, and are amplified through a rail-to rail amplifier chip AD8541ART, and then transferred to a meter, then the signal parameter read back by the HART instrument passes through the pin 18 of the low-power HART modem chip YT-HART, the analog signal is converted into a digital signal by the low-power HART modem chip YT-HART, and then the digital signal is converted back to the inside of the singlechip C8051F340 by the UART bus 2, and is sent back to the RS485 signal conversion module by the UART bus 1, and then the digital signal is converted back to the measurement and control equipment to perform networking data exchange.
In summary, compared with the prior art, the protocol conversion apparatus based on HART technology provided by the present invention has at least the following advantages:
(1) according to the invention, by analyzing and converting the RS485 and HART signals, the data bidirectional communication between instruments and meters with two different interfaces and communication protocols of HART and RS485 is realized;
(2) the invention solves the defects of low transmission rate of HART protocol and small quantity of networking instruments through the RS485 signal conversion module and the data analysis module, can improve the transmission rate to 10Mbps at most by using the RS485 interface, and increases the networking quantity to 320, so that the instruments with different brands and different protocols in the industrial field form a sensor measurement and control network.
It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. A protocol conversion device based on HART technology is characterized by comprising a measurement and control device and a plurality of RS485 and HART conversion circuits connected with the measurement and control device;
each RS485 and HART conversion circuit comprises a power management module, an RS485 signal conversion module, a data analysis module, a HART communication module and a HART instrument;
the RS485 signal conversion module, the data analysis module, the HART communication module and the HART instrument are sequentially connected;
the power management module provides power for each RS485 and HART conversion circuit;
the RS485 signal conversion module converts the received RS485 format signal and UART serial port data into each other;
the data analysis module analyzes the received UART serial port data according to a protocol;
the HART communication module converts the received UART serial port data and HART format signals mutually;
the signal transmission path from RS485 to HART is as follows:
the RS485 signal conversion module receives an RS485 format signal sent by the test equipment, converts the RS485 format signal into UART serial port data and transmits the UART serial port data to the data analysis module;
the data analysis module analyzes the received UART serial port data according to a protocol and then transmits the data to the HART communication module;
the HART communication module converts the acquired analysis data into HART format signals and transmits the HART format signals to a HART instrument;
otherwise, the HART to RS485 signaling can be accomplished in the reverse path.
2. The HART technology-based protocol conversion device of claim 1, wherein the number of RS485 and HART conversion circuits connected to the instrumentation and control equipment is at most 320.
3. The protocol conversion device according to claim 1, wherein the data analysis module comprises a single chip and a crystal oscillator circuit, the crystal oscillator circuit generates a qualified clock signal for the single chip, the single chip receives UART serial data of the RS485 signal conversion module, performs frame format conversion and then sends the data to the HART communication module, and the single chip receives UART serial data of the HART communication module, performs frame format conversion and then sends the data to the RS485 signal conversion module.
4. The HART technology-based protocol conversion device as claimed in claim 3, wherein the single-chip microcomputer should at least satisfy the following requirements: the device has the functions of power-on reset in system programming, 2 enhanced UART serial ports, 4 universal 16-bit counters/timers and 40I/O ports; the crystal oscillator circuit meets the required serial port standard.
5. The device as claimed in claim 3, wherein the HART communication module comprises a HART modem chip, a rail-to-rail amplifier chip and a CMOS analog switch.
6. The device as claimed in claim 5, wherein the CMOS analog switch is a single-pole single-throw analog switch, and has rail-to-rail output capability and TTL/CMOS logic compatibility, so as to realize adaptive switching of HART modes with different wire systems.
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| CN202010512138.5A CN113839903A (en) | 2020-06-08 | 2020-06-08 | Protocol conversion device based on HART technology |
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| CN202010512138.5A CN113839903A (en) | 2020-06-08 | 2020-06-08 | Protocol conversion device based on HART technology |
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Cited By (2)
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| CN115379023A (en) * | 2022-08-25 | 2022-11-22 | 国核自仪系统工程有限公司 | HART communication device |
| WO2023216362A1 (en) * | 2022-05-11 | 2023-11-16 | 上海辰竹仪表有限公司 | Hart circuit and state determination method for field interface thereof |
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