CN213276360U

CN213276360U - Multi-channel analog input module with HART protocol conversion

Info

Publication number: CN213276360U
Application number: CN202022653560.0U
Authority: CN
Inventors: 梁超宇; 蒋杰; 王维建
Original assignee: SHANGHAI XINHUA CONTROL TECHNOLOGY (GROUP) CO LTD
Current assignee: SHANGHAI XINHUA CONTROL TECHNOLOGY (GROUP) CO LTD
Priority date: 2020-11-16
Filing date: 2020-11-16
Publication date: 2021-05-25
Anticipated expiration: 2030-11-16

Abstract

The utility model discloses a multichannel analog input module with HART protocol conversion, keep apart unit, first multi-way switch unit and second multi-way switch unit including microcontroller, programmable logic device, HART modem, analog-to-digital converter, first isolation unit, second, microcontroller, programmable logic device communication connection, the input of first multi-way switch unit and second multi-way switch unit is connected to multichannel on-the-spot equipment after parallelly connected, and its control end is connected to the programmable logic device, first multi-way switch unit output warp HART modem, first isolation unit are connected to microcontroller, second multi-way switch unit output is connected to through analog-to-digital converter, second isolation unit the programmable logic device. The utility model discloses a realize the transmission of multichannel HART signal when analog input sampling.

Description

Multi-channel analog input module with HART protocol conversion

Technical Field

The utility model relates to an analog input module technical field especially relates to a multichannel analog input module with HART protocol conversion.

Background

At present, a Distributed Control System (DCS) has been widely used in the field of automation Control of power, petroleum, chemical industry, steel, paper making, cement, desulfurization, dust removal, water treatment, etc., and is a multi-level Computer System composed of a process Control level and a process monitoring level and using a Communication network as a link, and integrates 4C technologies such as a Computer (Computer), Communication (Communication), display (CRT), Control (Control), etc., and the basic idea is to perform Distributed Control, centralized operation, hierarchical management, flexible configuration, and convenient configuration.

The open communication protocol for Highway Addressable Remote Transducer (HART) is a communication protocol between field intelligent instruments and control room equipment introduced by rosemont in 1985. The HART protocol has become the industry standard for global smart meters at present.

In the prior art, an analog input module in the DCS system is only responsible for inputting an analog signal of 4-20mA, and does not unpack HART protocol messages, and cannot meet the functional requirements of information acquisition and device management of instruments and meters with HART protocols in an industrial field.

Accordingly, those skilled in the art have been directed to developing a multi-channel analog input module with HART protocol conversion to overcome the shortcomings of the prior art.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned defect of the prior art, the utility model aims to solve the technical problem that a multichannel analog input module for DCS system is provided, can realize the transmission of HART signal in analog input sampling, let analog input module can be undisturbed a plurality of channel data acquisition of realization and HART instrumentation's information acquisition and management through high-speed, low impedance change over switch to satisfy industrial field's needs.

In order to achieve the above object, the utility model provides a multichannel analog input module with HART protocol conversion, including microcontroller, programmable logic device, HART modem, analog-to-digital converter, first isolation unit, second isolation unit, first multi-way switch unit and second multi-way switch unit, microcontroller, programmable logic device communication connection, the input of first multi-way switch unit and second multi-way switch unit is connected to multichannel on-the-spot HART equipment after connecting in parallel, and its control end is connected to programmable logic device, first multi-way switch unit output warp HART modem, first isolation unit are connected to microcontroller, second multi-way switch unit output is connected to through analog-to-digital converter, second isolation unit programmable logic device.

Further, the microcontroller has a first serial bus interface, the HART modem has a serial port, and the serial port of the HART modem is connected to the first serial bus interface via the first isolation unit.

Further, the programmable logic device is provided with a second serial bus interface, the analog-digital converter is provided with a serial port, and the serial port of the analog-digital converter is connected to the second serial bus interface through the second isolation unit.

Further, the microcontroller is provided with a first local bus interface, the programmable logic device is provided with a second local bus interface, and the first local bus interface and the second local bus interface are connected through local bus communication.

Further, the programmable logic device has a dual-port RAM that is used as a buffer space for receiving data and transmitting data.

Further, the intelligent control system also comprises an RS485 transceiver, wherein the RS485 transceiver is connected to the programmable logic device and is used for exchanging data with an upper controller.

Further, the programmable logic device has a third serial bus interface, which is connected to the RS485 transceiver.

Further, the first isolation unit is a photoelectric coupler.

Further, the second isolation unit is a magnetic isolator.

Further, the programmable logic device is configured to control the first multi-way switch unit and the second multi-way switch unit to perform channel switching in a polling master-slave manner.

The beneficial effects of the utility model are that realized the transmission of multichannel HART signal when analog input sampling.

Drawings

Fig. 1 is a schematic block diagram of a preferred embodiment of the present invention.

Wherein, 1-a microcontroller; 2-programmable logic devices; a 3-HART modem; 4-an analog-to-digital converter; 51-a first isolation unit; 52-a second isolation unit; 61-a first multi-way switch unit; 62-a second multiplexing switching unit; 7-RS485 transceiver; 8-field HART device.

Detailed Description

The preferred embodiments of the present invention will be described below with reference to the accompanying drawings for clarity and understanding of the technical contents. The present invention may be embodied in many different forms of embodiments, and the scope of the invention is not limited to the embodiments described herein.

An embodiment of the utility model provides an analog input module that has HART protocol conversion for DCS system. And the HART protocol signals on a plurality of channels are acquired by switching the multi-way switch, so that the requirement of an industrial field is met. One example of this embodiment provides for the input of a 16 channel analog 4-20mA signal, i.e., 16 different field HART devices may be monitored via one analog input module. And the support to HART protocol is provided, the microcontroller controls the multi-way switch to switch, and HART equipment on each channel can be monitored in turn without disturbance by a polling master-slave mode.

As shown in fig. 1, the analog input module of the present embodiment is composed of a microcontroller 1, a programmable logic device (CPLD)2, a HART modem 3, an analog-to-digital converter 4, a multiplexer unit, and an isolation unit.

The multi-way switching unit includes a first multi-way switching unit 61 and a second multi-way switching unit 62. The isolation unit includes a first isolation unit 51 and a second isolation unit 52.

In this embodiment, the first multi-way switch unit 61 and the second multi-way switch unit 62 are respectively composed of two MUX508 analog multiplexer chips. The first multiplexer unit 61 switches channels of the 16 field HART devices 8 and inputs the channels to the signal input port of the HART modem 3. The second multiplexer unit 62 switches channels of the 16 field HART devices 8 and inputs the signals to the signal input port of the adc 4, so as to implement a single-module multi-channel application.

In this embodiment, the microcontroller 1 is mainly responsible for data processing of HART protocol, and it adopts a Cortex-M0 series chip (M0516LBN) of 32-bit ARM architecture, and is programmed by C language.

The HART modem 3 uses a5191HRT type chip as a HART protocol decoding chip, which can demodulate the signal switched by the field HART device 8 through the first multi-way switch unit 61, so as to realize the preprocessing of HART information. The HART protocol communication can also be accomplished by superimposing the modulated HART signal of 1.2kHz on the analog signal of 4-20mA through the first multiplexer unit 61. Meanwhile, the HART modem 3 also provides a serial port, which can communicate with the microcontroller 1. The microcontroller 1 realizes bidirectional communication with the HART modem 3 through the first isolation unit 51 via the built-in serial bus interface 11, reads HART protocol information on the switched signal channel, and completes data storage.

The first isolation unit 51 uses three photocoupler isolation chips EL357, which are located between the microcontroller 1 and the HART modem 3, to realize the isolation of the two-way communication between the microcontroller 1 and the HART modem 3, and its purpose is to prevent the abnormal external signal from impacting and damaging the internal circuit of the analog input module, and ensure the normal operation of the module.

In this embodiment, the analog-to-digital converter 4 uses the a/D converter ADS8320 chip, and can convert the 4-20mA analog quantity signal into a digital quantity signal, and the conversion result is isolated by the second isolation unit 52 and then transmitted to the programmable logic device 2.

In this embodiment, the second isolation unit 52 is a high-speed magnetic medium isolation chip, which can isolate interference of the field device on the programmable logic device 2 and ensure normal operation thereof. Specifically, the second isolation unit 52 employs two ADuM1200 digital isolator chips, which have the excellent characteristics of low power consumption, small size, high data transmission rate, and high anti-interference performance. In the use process of the embodiment, the function of converting and isolating the external signal and the internal circuit signal is realized.

The programmable logic device 2 in this embodiment is an LCMXO2-2000 chip from the LATTICE MachXO2 family and is programmed using Verilog language. The programmable logic device 2 mainly completes communication with an upper controller, sends analog quantity and state parameters of field HART equipment 8 to an operator station for processing, and in addition, the programmable logic device 2 also controls the switching of the first multi-way switch unit 61 and the second multi-way switch unit 62, so that selected input signal channels are conducted, input signals of 16 channels sequentially enter the analog-digital converter 4 for analog-digital conversion, and data exchange is carried out between the input signals and the microcontroller 1. Because the DCS system has the functional characteristics that the real-time response index of communication with an upper controller is required to be high, and the DCS system is stable and reliable, a double-port RAM 23 is used as a buffer space for receiving data and sending data in the programmable logic device 2, a third serial BUS interface 24(BUS _ A) is realized by hardware, and data exchange is carried out with the upper controller through the RS485 transceiver 7. The RS485 transceiver 7 adopts an ISL81487 chip, has the characteristics of low power consumption and high communication rate, and meets the high-speed real-time data communication requirement between field IO and a controller under a DCS system.

The programmable logic device 2 is also designed with a second serial bus interface 21 for a/D sampling logic inside to realize the acquisition of analog quantity.

A 16-bit second local BUS interface 22(BUS _ C) is also implemented in the programmable logic device 2 in hardware. The microcontroller 1 and the programmable logic device 2 are in communication connection through a local BUS (local BUS) between a first local BUS interface 12(BUS _ C) in the microcontroller 1 and a second local BUS interface 22(BUS _ C) in the programmable logic device 2, and bidirectional interactive communication is performed to realize data exchange.

The foregoing has described in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the teachings of this invention without undue experimentation. Therefore, the technical solutions that can be obtained by a person skilled in the art through logic analysis, reasoning or limited experiments based on the prior art according to the concepts of the present invention should be within the scope of protection defined by the claims.

Claims

1. The utility model provides a multichannel analog input module with HART protocol conversion which characterized in that, includes microcontroller, programmable logic device, HART modem, analog-to-digital converter, first isolation unit, second isolation unit, first multi-way switch unit and second multi-way switch unit, microcontroller, programmable logic device communication connection, the input of first multi-way switch unit and second multi-way switch unit is connected to multichannel field HART equipment after parallelly connected, and its control end is connected to programmable logic device, first multi-way switch unit output warp HART modem, first isolation unit are connected to microcontroller, second multi-way switch unit output is connected to through analog-to-digital converter, second isolation unit the programmable logic device.

2. The multi-channel analog input module with HART protocol conversion of claim 1, wherein the microcontroller has a first serial bus interface, the HART modem has a serial port, and the serial port of the HART modem is connected to the first serial bus interface via the first isolation unit.

3. The multi-channel analog input module with HART protocol conversion of claim 1, wherein the programmable logic device has a second serial bus interface, the analog-to-digital converter has a serial port, and the serial port of the analog-to-digital converter is connected to the second serial bus interface via the second isolation unit.

4. The multi-channel analog input module with HART protocol conversion of claim 1, wherein the microcontroller has a first local bus interface, the programmable logic device has a second local bus interface, and the first local bus interface and the second local bus interface are communicatively coupled via a local bus.

5. The multi-channel analog input module with HART protocol conversion of claim 1, wherein the programmable logic device has a dual port RAM used as a buffer space for receiving and transmitting data.

6. The multi-channel analog input module with HART protocol conversion of claim 1, further comprising an RS485 transceiver, wherein the RS485 transceiver is connected to the programmable logic device for data exchange with a host controller.

7. The multi-channel analog input module with HART protocol conversion of claim 6, wherein the programmable logic device has a third serial bus interface, the third serial bus interface being connected to the RS485 transceiver.

8. The multi-channel analog input module with HART protocol conversion of claim 1, wherein the first isolation unit is an optocoupler.

9. The multi-channel analog input module with HART protocol conversion of claim 1, wherein the second isolation unit is a magnetic isolator.

10. The multi-channel analog input module with HART protocol conversion of claim 1, wherein the programmable logic device is configured to control the first multiplexer unit and the second multiplexer unit to switch channels in a polling master-slave manner.