Control device and control method thereof

Abstract

The invention provides a control device and a control method thereof. The control device is characterized in that an HART instrument is connected with an input module of a DCSPLC system through an HART signal filter; the HART instrument is used for transmitting the HART signal to the HART signal filter; the HART signal filter is used for filtering interference signals in the HART signals and transmitting the filtered HART signals to the input module of the DCSPLC system. According to the control device, the HART signal filter is additionally arranged on the basis of an original control device, interference signals in the HART signals transmitted by the HART instrument are filtered through the HART signal filter, the filtered HART signals are transmitted to the input module of the DCSPLC system, interference of the interference signals on the input module of the DCSPLC system is avoided, and errors of the DCSPLC system are avoided.

Description

Technical Field

[0001] The present disclosure relates to the technical field of control systems, and in particular to a control device and a control method thereof. Background Art

[0002] HART (Highway Addressable Remote Transducer), an addressable remote transmitter high-speed communication protocol, is a two-way, open communication protocol widely used in the field of automation control technology. It has been widely used in the communication between field intelligent instruments and control room equipment. More and more field instruments, such as temperature and humidity transmitters, pressure sensors, flow meters, liquid level meters, etc., are gradually beginning to support the HART protocol. The HART signal is transmitted through the original analog loop, and two-way digital communication is achieved by superimposing a 1.2K / 2.2K Hz frequency shift keying (FSK) signal on the original 4-20mA DC signal. Advanced control functions including remote process variable query, parameter setting, and diagnostic information query can be transmitted. However, at the control end of the DCS\PLC system, there are still many old devices that do not support the HART protocol. If these devices are only equipped with HART instruments, the high-frequency communication signals emitted by the instruments may interfere with the control module of the DCS\PLC, causing system errors. Summary of the invention

[0003] The technical problem to be solved by the present disclosure is to overcome the defect in the prior art that the high-frequency communication signal emitted by the HART instrument will interfere with the control module in the DCS / PLC system, causing errors in the DCS / PLC system, and provide a control device and a control method thereof.

[0004] The present invention solves the above technical problems through the following technical solutions:

[0005] A first aspect of the present disclosure provides a control device, including a HART signal filter, a HART instrument, and an input module of a DCS\PLC system;

[0006] The HART instrument is connected to the input module of the DCS\PLC system through the HART signal filter;

[0007] The HART instrument is used to transmit the HART signal to the HART signal filter;

[0008] The HART signal filter is used to filter the interference signal in the HART signal and transmit the filtered HART signal to the input module of the DCS\PLC system.

[0009] Preferably, the input module of the DCS\PLC system is used to transmit the analog signal to the HART signal filter;

[0010] The HART signal filter is also used to filter the received analog signal and transmit it to the HART instrument;

[0011] The HART instrument is used to switch to a corresponding function according to the received filtered analog signal.

[0012] Preferably, the HART signal filter comprises a PCB board, a housing upper cover, a housing base, a panel, wiring terminals and fastening screws;

[0013] The PCB board, the housing upper cover, and the housing base are connected by fastening screws, the panel is mounted on the housing upper cover, and the connection terminals are mounted on the PCB board.

[0014] Preferably, the panel is mounted on the upper cover of the housing by gluing.

[0015] Preferably, the housing upper cover and the housing base are both made of metal or plastic.

[0016] Preferably, the HART signal filter includes a fuse, an inductor, a first resistor, a second resistor, a first capacitor, a second capacitor, a third capacitor, an FLD+ terminal, an FLD- terminal, a SYS+ terminal, a SYS- terminal, a COM+ terminal and a COM- terminal;

[0017] One end of the fuse is electrically connected to the SYS+ terminal, the other end of the fuse is electrically connected to one end of the inductor, the other end of the inductor is respectively electrically connected to one end of the second resistor and one end of the first capacitor, the other end of the second resistor is electrically connected to the FLD+ terminal, the other end of the first capacitor is electrically connected to the COM+ terminal, one end of the third capacitor is respectively electrically connected to the other end of the fuse and one end of the inductor, the other end of the third capacitor is respectively electrically connected to the SYS- terminal, the FLD- terminal and one end of the first resistor, the other end of the first resistor is electrically connected to one end of the second capacitor, and the other end of the second capacitor is electrically connected to the COM- terminal.

[0018] Preferably, the fuse is used to prevent the HART signal filter from short-circuiting;

[0019] The first resistor and the second resistor are used to limit the current of the HART signal filter;

[0020] The inductor is used to block high-frequency signals and pass low-frequency signals;

[0021] The first capacitor, the second capacitor and the third capacitor are all used to block low-frequency signals and pass high-frequency signals.

[0022] Preferably, the control device further comprises a HART communication monitoring network, and the HART signal filter comprises a COM+ terminal and a COM- terminal;

[0023] The HART signal filter is connected to the HART communication monitoring network through the COM+ terminal and the COM- terminal.

[0024] Preferably, the HART signal filter includes an FLD+ terminal, an FLD- terminal, a SYS+ terminal, and a SYS- terminal, and the input module of the DCS\PLC system includes a CH+ terminal and a CH- terminal;

[0025] The HART instrument is connected to the HART signal filter through the FLD+ terminal and the FLD- terminal, and the HART signal filter is connected to the input module of the DCS\PLC system through the SYS+ terminal and the SYS- terminal.

[0026] A second aspect of the present disclosure provides a control method, which is applicable to the control device according to the first aspect, and is applied to the HART signal filter, and includes:

[0027] Receive HART signals transmitted by HART instruments;

[0028] The interference signal in the HART signal is filtered, and the filtered HART signal is transmitted to the input module of the DCS\PLC system.

[0029] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present disclosure.

[0030] The positive and progressive effects of this disclosure are:

[0031] The present invention adds a HART signal filter on the basis of the original control device, filters the interference signal in the HART signal transmitted by the HART instrument through the HART signal filter, and transmits the filtered HART signal to the input module of the DCS\PLC system, thereby avoiding interference with the input module of the DCS\PLC system caused by the interference signal, thereby avoiding errors in the DCS\PLC system. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the structure of a control device provided in Example 1 of the present disclosure.

[0033] Figure 2 This is a schematic diagram of the structure of the HART signal filter provided in Example 1 of the present disclosure.

[0034] Figure 3 This is a circuit schematic diagram of the HART signal filter provided in Example 1 of the present disclosure.

[0035] Figure 4 A flow chart of a control method provided in Example 2 of the present disclosure. DETAILED DESCRIPTION

[0036] The present disclosure is further described below by way of examples, but the present disclosure is not limited to the scope of the examples.

[0037] Prefixes such as "first" and "second" are used in the embodiments of the present disclosure only to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers to distinguish description objects in the embodiments of the present disclosure does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and no unnecessary limitation should be constituted due to the use of such prefixes. In addition, in the description of the present embodiment, unless otherwise specified, the meaning of "plurality" is two or more.

[0038] In the embodiments of the present disclosure, the collection, storage, use, processing, transmission, provision and disclosure of user personal information involved are in compliance with the provisions of relevant laws and regulations and do not violate public order and good morals.

[0039] Example 1

[0040] Figure 1 A control device is provided in Embodiment 1 of the present disclosure, such as Figure 1 As shown, taking the number of HART signal filters and the number of HART instruments as two as an example, the control device includes a HART signal filter, a HART instrument and an input module of a DCS\PLC system;

[0041] The HART instrument is connected to the input module of the DCS\PLC system through the HART signal filter;

[0042] A HART instrument for transmitting a HART signal to a HART signal filter;

[0043] The HART signal filter is used to filter interference signals in the HART signal and transmit the filtered HART signal to the input module of the DCS\PLC system.

[0044] In this embodiment, the input module of the DCS\PLC system is an analog input module of the DCS\PLC system.

[0045] It should be noted that the HART signal filter disclosed in the present invention uses a fuse in the main circuit. This design can effectively disconnect the HART instrument and the DCS\PLC system when a short circuit is caused by a HART instrument failure, ensuring that the failure will not spread to other instruments.

[0046] In addition, the HART signal filter disclosed in the present invention adopts a pluggable terminal block. This design does not require unplugging of the wires when replacing the filter, thus meeting the need for rapid maintenance.

[0047] The purpose of this disclosure is to design a HART signal filter, which is installed between the HART instrument and the input module of the DCS\PLC system, which can achieve the penetration of 4-20mA analog control signals and the filtering of HART signals, thereby avoiding the input module of the DCS\PLC system from being disturbed and making errors. It also allows input modules that do not support HART to adapt to HART instruments.

[0048] In an optional embodiment, the input module of the DCS\PLC system is used to transmit the analog signal to the HART signal filter;

[0049] In this embodiment, the analog signal is a DC signal.

[0050] The HART signal filter is also used to filter the received analog signal and transmit it to the HART instrument;

[0051] The HART instrument is used to switch to a corresponding function according to the received filtered analog signal.

[0052] In an optional embodiment, if Figure 2 As shown, the HART signal filter includes a PCB board 1, a housing cover 2, a housing base 3, a panel 4, a wiring terminal 5 and a fastening screw 6;

[0053] The PCB board 1 , the housing upper cover 2 , and the housing base 3 are connected by fastening screws 6 , the panel 4 is mounted on the housing upper cover 2 , and the wiring terminal 5 is mounted on the PCB board 1 .

[0054] In an optional embodiment, the panel is mounted on the upper cover of the housing by gluing.

[0055] In an optional embodiment, the housing cover and the housing base are both made of metal or plastic.

[0056] In an optional embodiment, if Figure 3As shown, the HART signal filter includes a fuse F1, an inductor L1, a first resistor R1, a second resistor R2, a first capacitor C1, a second capacitor C2, a third capacitor C3, an FLD+ terminal, an FLD- terminal, a SYS+ terminal, a SYS- terminal, a COM+ terminal and a COM- terminal;

[0057] One end of the fuse F1 is electrically connected to the SYS+ terminal, the other end of the fuse F1 is electrically connected to one end of the inductor L1, the other end of the inductor L1 is respectively electrically connected to one end of the second resistor R2 and one end of the first capacitor C1, the other end of the second resistor R2 is electrically connected to the FLD+ terminal, the other end of the first capacitor C1 is electrically connected to the COM+ terminal, one end of the third capacitor C3 is respectively electrically connected to the other end of the fuse F1 and one end of the inductor L1, the other end of the third capacitor C3 is respectively electrically connected to the SYS- terminal, the FLD- terminal and one end of the first resistor R1, the other end of the first resistor R1 is electrically connected to one end of the second capacitor C2, and the other end of the second capacitor C2 is electrically connected to the COM- terminal.

[0058] It should be noted that the HART signal filter disclosed in the present invention uses current limiting resistors in both the main loop and the communication monitoring loop. When any component in the loop fails and causes a surge current, or the loop is subject to strong interference, the current amplitude is effectively reduced, thereby protecting the safety of the communication chip in the HART instrument and the DCS\PLC input module.

[0059] In an optional embodiment, a fuse is used to prevent the HART signal filter from short-circuiting;

[0060] The first resistor and the second resistor are used to limit the current of the HART signal filter;

[0061] Inductors are used to block high-frequency signals and pass low-frequency signals;

[0062] The first capacitor, the second capacitor and the third capacitor are all used to block low-frequency signals and pass high-frequency signals.

[0063] In an optional embodiment, if Figure 1 As shown, the control device also includes a HART communication monitoring network, and the HART signal filter includes a COM+ terminal and a COM- terminal;

[0064] The HART signal filter is connected to the HART communication monitoring network through the COM+ terminal and the COM- terminal.

[0065] It should be noted that the HART signal filter disclosed in the present invention is designed with a communication port and a capacitor isolator between the 4-20mA line and the HART monitoring network, thereby achieving safe isolation between the 4-20mA line and the HART communication monitoring network.

[0066] In an optional embodiment, the HART signal filter includes an FLD+ terminal, an FLD- terminal, a SYS+ terminal, and a SYS- terminal, and the input module of the DCS\PLC system includes a CH+ terminal and a CH- terminal;

[0067] The HART instrument is connected to the HART signal filter through the FLD+ terminal and the FLD- terminal, and the HART signal filter is connected to the input module of the DCS\PLC system through the SYS+ terminal and the SYS- terminal.

[0068] In the specific implementation process, Figure 1 As shown, the HART instrument is connected to the FLD+ terminal and the FLD- terminal, the SYS+ terminal and the SYS- terminal are connected to the channel CH+ terminal and the CH- terminal of the analog input module (AI) of the DCS\PLC system, and the COM+ terminal and the COM- terminal can be connected to the HART communication monitoring network.

[0069] The 4-20mA analog signal (i.e., DC signal) is sent from the channel CH+ terminal and CH- terminal of the analog input module (AI) of the DCS\PLC system, and is connected to the HART instrument through the fuse F1, the inductor L1, and the second resistor R2. Since the inductor L1 has a low impedance characteristic for DC signals, the 4-20mA analog signal can reach the HART instrument smoothly without being blocked; the high-frequency interference communication signal in the loop (it should be noted that the high-frequency interference communication signal may be generated by the HART signal or by other input interference) is released through the third capacitor C3 and will not affect the HART instrument; since the first capacitor C1 and the second capacitor C2 have high impedance for DC signals, the 4-20mA analog signal cannot reach the COM+ terminal and the COM- terminal, thereby realizing the isolation of the DCS\PLC system and the HART communication monitoring network;

[0070] The 1.2K\2.2K FSK HART signal emitted by the HART instrument, when passing through the inductor L1, is blocked by the inductor L1 and cannot reach the SYS+ terminal and the SYS- terminal because the inductor L1 presents high impedance to high-frequency signals, thereby avoiding the interference of the HART signal on the analog input module (AI) of the DCS\PLC system; when passing through the first capacitor C1 and the second capacitor C2, the first capacitor C1 and the second capacitor C2 present low impedance to high-frequency signals, so the signal can smoothly reach the COM+ terminal and the COM- terminal, thereby realizing the monitoring of the HART network signal;

[0071] It should be noted that the HART signal filter disclosed in the present invention is specially designed for the adaptation problem between instruments with HART function and DCS\PLC IO modules that do not support HART function. It uses filter inductors and filter capacitors, and has the function of perfectly filtering out 1.2K\2.2K FSK HART signals, while ensuring the smooth passage of 4~20mA analog signals.

[0072] In addition, if Figure 1 Each HART signal filter is respectively provided with a set of FLD+ terminal and FLD- terminal, a set of SYS+ terminal and SYS- terminal, and a set of COM+ terminal and COM- terminal. Two HART signal filters are respectively connected to two HART instruments, that is, the number of HART signal filters is the same as the number of HART instruments.

[0073] Furthermore, in addition to Figure 1 In addition to the case where the two HART signal filters shown are respectively connected to two HART instruments, multiple HART instruments can also be connected through one HART signal filter. Specifically, multiple groups of FLD+ terminals and FLD- terminals, multiple groups of SYS+ terminals and SYS- terminals, and multiple groups of COM+ terminals and COM- terminals are set in the HART signal filter. The number of groups of FLD+ terminals and FLD- terminals, the number of groups of SYS+ terminals and SYS- terminals, and the number of groups of COM+ terminals and COM- terminals are consistent with the number of HART instruments.

[0074] The present invention adds a HART signal filter on the basis of the original control device, filters the interference signal in the HART signal transmitted by the HART instrument through the HART signal filter, and transmits the filtered HART signal to the input module of the DCS\PLC system, thereby avoiding interference with the input module of the DCS\PLC system caused by the interference signal, thereby avoiding errors in the DCS\PLC system.

[0075] Example 2

[0076] Corresponding to the aforementioned control device embodiment, the present disclosure also provides an embodiment of a control method.

[0077] Figure 4 This is a flow chart of a control method provided in Example 2 of the present disclosure. The control method is applicable to the control device described in Example 1. The control method is applied to a HART signal filter, such as Figure 4 As shown, the control method includes:

[0078] S1, receiving the HART signal transmitted by the HART instrument;

[0079] S2. Filter the interference signal in the HART signal and transmit the filtered HART signal to the input module of the DCS\PLC system.

[0080] In this embodiment, the input module of the DCS\PLC system is an analog input module of the DCS\PLC system.

[0081] It should be noted that the HART signal filter disclosed in the present invention uses a fuse in the main circuit. This design can effectively disconnect the HART instrument and the DCS\PLC system when a short circuit is caused by a HART instrument failure, ensuring that the failure will not spread to other instruments.

[0082] In addition, the HART signal filter disclosed in the present invention adopts a pluggable terminal block. This design does not require unplugging of the wires when replacing the filter, thus meeting the need for rapid maintenance.

[0083] The control method in this embodiment is applicable to the control device described in Example 1, and the specific implementation method is the same as the control device in Example 1, which will not be described again here.

[0084] The present invention adds a HART signal filter on the basis of the original control device, filters the interference signal in the HART signal transmitted by the HART instrument through the HART signal filter, and transmits the filtered HART signal to the input module of the DCS\PLC system, thereby avoiding interference with the input module of the DCS\PLC system caused by the interference signal, thereby avoiding errors in the DCS\PLC system.

[0085] Although the specific embodiments of the present disclosure are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present disclosure is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, but these changes and modifications all fall within the protection scope of the present disclosure.

Claims

1. A control device, characterized in that: Including HART signal filter, HART instrument and input module of DCS\PLC system; The HART instrument is connected to the input module of the DCS\PLC system through the HART signal filter; The HART instrument is used to transmit the HART signal to the HART signal filter; The HART signal filter is used to filter the interference signal in the HART signal and transmit the filtered HART signal to the input module of the DCS\PLC system.

2. The control device according to claim 1, characterized in that The input module of the DCS\PLC system is used to transmit the analog signal to the HART signal filter; The HART signal filter is also used to filter the received analog signal and transmit it to the HART instrument; The HART instrument is used to switch to a corresponding function according to the received filtered analog signal.

3. The control device according to claim 1, characterized in that: The HART signal filter comprises a PCB board, a housing cover, a housing base, a panel, wiring terminals and fastening screws; The PCB board, the housing upper cover, and the housing base are connected by fastening screws, the panel is mounted on the housing upper cover, and the connection terminals are mounted on the PCB board.

4. The control device according to claim 3, characterized in that: The panel is installed on the upper cover of the shell by gluing.

5. The control device according to claim 3, characterized in that: The housing upper cover and the housing base are both made of metal or plastic.

6. The control device according to claim 1, characterized in that: The HART signal filter includes a fuse, an inductor, a first resistor, a second resistor, a first capacitor, a second capacitor, a third capacitor, an FLD+ terminal, an FLD- terminal, a SYS+ terminal, a SYS- terminal, a COM+ terminal and a COM- terminal; One end of the fuse is electrically connected to the SYS+ terminal, the other end of the fuse is electrically connected to one end of the inductor, the other end of the inductor is respectively electrically connected to one end of the second resistor and one end of the first capacitor, the other end of the second resistor is electrically connected to the FLD+ terminal, the other end of the first capacitor is electrically connected to the COM+ terminal, one end of the third capacitor is respectively electrically connected to the other end of the fuse and one end of the inductor, the other end of the third capacitor is respectively electrically connected to the SYS- terminal, the FLD- terminal and one end of the first resistor, the other end of the first resistor is electrically connected to one end of the second capacitor, and the other end of the second capacitor is electrically connected to the COM- terminal.

7. The control device according to claim 6, characterized in that The fuse is used to prevent the HART signal filter from short-circuiting; The first resistor and the second resistor are used to limit the current of the HART signal filter; The inductor is used to block high-frequency signals and pass low-frequency signals; The first capacitor, the second capacitor and the third capacitor are all used to block low-frequency signals and pass high-frequency signals.

8. The control device according to claim 1, characterized in that: The control device also includes a HART communication monitoring network, and the HART signal filter includes a COM+ terminal and a COM- terminal; The HART signal filter is connected to the HART communication monitoring network through the COM+ terminal and the COM- terminal.

9. The control device according to claim 1, characterized in that: The HART signal filter includes an FLD+ terminal, an FLD- terminal, a SYS+ terminal, and a SYS- terminal, and the input module of the DCS\PLC system includes a CH+ terminal and a CH- terminal; The HART instrument is connected to the HART signal filter through the FLD+ terminal and the FLD- terminal, and the HART signal filter is connected to the input module of the DCS\PLC system through the SYS+ terminal and the SYS- terminal.

10. A control method, characterized in that: The control method is applicable to the control device according to claims 1 to 9, and the control method is applied to the HART signal filter. The control method includes: Receive HART signals transmitted by HART instruments; The interference signal in the HART signal is filtered, and the filtered HART signal is transmitted to the input module of the DCS\PLC system.

Images