Diagnostic Systems

Abstract

To facilitate investigation of the HART communication status.SOLUTION: A HART modem 3 includes: a HART / host communication conversion unit 31 that relays communication between a HART device 1 and a HART host apparatus 5 or diagnostic apparatus 2; and a communication interface unit 33 that transmits HART communication commands transmitted to the HART device 1 and responses received from the HART device 1 to the diagnostic apparatus 2. The diagnostic apparatus 2 includes: a communication interface unit 20 that receives the commands and responses transmitted from the HART modem 3; a communication protocol analysis unit 22 that converts the received commands and responses into character strings indicating their contents; and a display unit 21 that displays the character string obtained by the communication protocol analysis unit 22.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a diagnostic system capable of investigating the status of HART communications. [Background technology]

[0002] HART (Highway Addressable Remote Transducer) communication is a communication method that superimposes a digital signal on a 4 to 20 mA direct current signal (analog signal) used in a control system. HART communication is used to configure devices by replacing the field equipment (devices) of an existing control system with HART-compatible products and connecting a HART-compatible configurator (setting device) to the analog signal line. HART communication is also used to send and receive measurement data from devices for monitoring and control, and to send and receive self-diagnosis results from devices to determine the soundness of measurement values ​​and the timing of device replacement in an equipment management system connected in parallel to the control system (see Patent Document 1).

[0003] Although the product lifespan of control systems is long, at 30 years or more, the advantage of HART communication for users is that they can continue to use their existing control systems as is, and exchange data simply by replacing devices with HART-compatible ones and adding (connecting in parallel) a configurator or device management system (collectively called a HART host) to the control system.

[0004] However, depending on the wiring conditions of the analog signal lines, there may be a shortage of the load resistance required for HART communication, or the analog signal lines may be installed in a noisy environment that interferes with HART communication, which can make the HART communication desired by the user impossible or unstable.

[0005] After installing the HART device and HART host, if an error occurs in reading or writing in HART communication, the cause will be investigated by measuring the voltage with a multimeter (tester), investigating the noise level with an oscilloscope, investigating the digital communication waveform of the command issued by the HART host, and investigating the digital communication waveform of the response issued by the HART device to the command. If necessary, the cause of the communication error will be identified by using various equipment, such as checking the contents of the communication data with a protocol analyzer.

[0006] In field service work that handles HART devices, there are times when it is necessary to investigate the communication status due to instability of HART communication. However, since investigation equipment is not usually carried around, there is a problem that even when encountering a situation where it is necessary to investigate a problem on-site, the necessary equipment may not be on hand. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2015-64766 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made to solve the above-mentioned problems, and has an object to provide a diagnostic system that can easily investigate the status of HART communication. [Means for solving the problem]

[0009] The diagnostic system of the present invention comprises a diagnostic device and a HART modem relaying communication between a field device and a higher-level host device or the diagnostic device, the HART modem comprising a communication conversion unit configured to relay communication between the field device and the host device or the diagnostic device, and a first communication interface unit configured to transmit a HART communication command transmitted to the field device and a response received from the field device to the diagnostic device, and the diagnostic device comprises a second communication interface unit configured to receive the command and response transmitted from the HART modem, a communication protocol analysis unit configured to convert the received command and response into character strings indicating their contents, and a display unit configured to display the character string obtained by the communication protocol analysis unit.

[0010] Further, a diagnostic system of the present invention comprises a diagnostic device and a HART modem relaying communication between a field device and a higher-level host device or the diagnostic device, the HART modem comprising a communication conversion unit configured to relay communication between the field device and the host device or the diagnostic device, a first communication interface unit configured to transmit a HART communication command transmitted to the field device and a response received from the field device to the diagnostic device and to receive a character string transmitted from the diagnostic device, and a record management unit configured to record the received character string in a storage medium attached to the HART modem, and the diagnostic device comprises a communication protocol analysis unit configured to convert the command and response transmitted from the HART modem into the character string indicating the contents of the command and response, and a second communication interface unit configured to receive the command and response transmitted from the HART modem and to transmit the character string obtained by the communication protocol analysis unit to the HART modem. Effect of the Invention

[0011] Furthermore, in the present invention, by transmitting HART communication commands and responses to a diagnostic device and converting the commands and responses into character strings in the diagnostic device, it is possible to display character strings indicating the contents of the commands and responses in the diagnostic device.

[0012] Furthermore, in the present invention, a command and a response of HART communication are transmitted to a diagnostic device, the diagnostic device converts the command and the response into character strings and transmits them to the HART modem, and the character string received by the HART modem is recorded in a storage medium, so that the character string recorded in the storage medium can be confirmed by an external device. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a block diagram showing a configuration of a diagnostic system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a flow chart illustrating the communication function of the HART modem according to the embodiment of the present invention. [Diagram 3] FIG. 3 is a flowchart illustrating the signal waveform display function of the HART modem according to the embodiment of the present invention. [Figure 4] FIG. 4 is a flowchart illustrating the signal waveform display function of the diagnostic device according to the embodiment of the present invention. [Diagram 5] FIG. 5 is a flowchart illustrating the communication protocol analysis function of the HART modem according to the embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart illustrating a communication protocol analysis function of the diagnostic device according to the embodiment of the present invention. [Figure 7] FIG. 7 is a flowchart illustrating the communication recording function of the HART modem according to the embodiment of the present invention. [Figure 8] FIG. 8 is a flow chart illustrating the communication recording function of the diagnostic device according to the embodiment of the present invention. [Figure 9] FIG. 9 is a flowchart illustrating the wave height measurement function of the HART modem according to the embodiment of the present invention. [Figure 10]FIG. 10 is a flowchart illustrating the wave height measurement function of the diagnostic device according to the embodiment of the present invention. [Figure 11] FIG. 11 is a flowchart illustrating the communication status diagnosis function of the HART modem according to the embodiment of the present invention. [Figure 12] FIG. 12 is a flowchart illustrating the communication status diagnostic function of the diagnostic device according to the embodiment of the present invention. [Figure 13] FIG. 13 is a flowchart illustrating the power supply status diagnosis function of the HART modem according to the embodiment of the present invention. [Figure 14] FIG. 14 is a flowchart illustrating the power supply status diagnosis function of the diagnosis device according to the embodiment of the present invention. [Figure 15] FIG. 15 is a flowchart illustrating the determination function of the HART modem according to an embodiment of the present invention. [Figure 16] FIG. 16 is a flowchart illustrating the determination function of the diagnostic device according to the embodiment of the present invention. [Figure 17] FIG. 17 is a block diagram showing an example of the configuration of a computer that realizes a HART modem according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a block diagram showing the configuration of a diagnostic system according to an embodiment of the present invention. The diagnostic system is composed of a HART device 1, which is a field device such as a pressure transmitter or a positioner, a diagnostic device 2, and a HART modem 3, which is a communication device that relays communication between the HART device 1 and the diagnostic device 2 or a host device 5.

[0015] The diagnostic device 2 includes a communication interface unit 20 that controls communication with the HART modem 3, a display unit 21 that displays images and measurement results by the HART modem 3, a communication protocol analysis unit 22 that converts commands and responses sent from the HART modem 3 into character strings indicating their contents, a designation unit 23 that designates communications to be permitted for the HART modem 3 or devices to be connected, an operation unit 24 that allows the user to give instructions to the diagnostic device 2, and a communication waveform generation unit 25 that generates an image for displaying the signal waveform indicated by the received data when data sent from the HART modem 3 is received.

[0016] The HART modem 3 includes a HART communication unit 30 that controls communication with the HART device 1, a HART / host communication conversion unit 31 that performs conversion processing between frequency signals (HART signals) and digital signals, a data management unit 32 that manages data within the HART modem 3 and measures the communication status, a communication interface unit 33 that controls communication with the diagnostic device 2 or the host device 5, a communication waveform detection unit 34 that generates data by sampling frequency signals transmitted and received between the HART device 1, a power supply status confirmation unit 36 ​​that measures the DC voltage of the analog signal lines 10 and 11 that connect the HART device 1 and the HART modem 3, a status display unit 37 that displays the measurement results by the HART modem 3, and a communication interface unit 38 that receives a designation of a device to be connected from the diagnostic device 2 and outputs a status to the HART modem 3. The device is equipped with a connection target management unit 38 that decides whether to allow processing, a record management unit 39 that records the data generated by the communication waveform detection unit 34, the command and response, and character strings indicating the contents of the command and response in a storage medium 40 attached to the slot 41, a knowledge database 42 that stores the HART protocol specifications and knowledge of past HART communication diagnosis, a judgment unit 43 that refers to the knowledge database 42 and judges whether the measurement results comply with the HART protocol specifications and whether the measurement results are consistent with the knowledge of past HART communication diagnosis, and an instruction unit 44 that obtains from the knowledge database 42 a method of dealing with the measurement results when they do not comply with the HART protocol specifications or are inconsistent with the knowledge of past HART communication diagnosis.

[0017] Reference numeral 4 in FIG. 1 denotes a power supply or an I / O module that supplies a power supply voltage to the HART device 1 via analog signal lines 10 and 11 .

[0018] Fig. 2 is a flowchart explaining the communication function of the HART modem 3. The communication interface unit 33 of the HART modem 3 receives a digital signal (command) transmitted from the host device 5 constituting the device management system via the communication interface unit 20 (Fig. 2, step S100). The HART / host communication conversion unit 31 of the HART modem 3 converts the command passed from the communication interface unit 33 via the data management unit 32 into a frequency signal (step S101 in FIG. 2).

[0019] The HART communication unit 30 of the HART modem 3 superimposes the frequency signal obtained by the HART / host communication conversion unit 31 onto a 4 to 20 mA current signal, and sends it out to the analog signal lines 10 and 11 (Step S102 in FIG. 2). In this way, commands can be sent to the HART device 1.

[0020] Next, the HART communication unit 30 extracts the frequency signal superimposed on the 4 to 20 mA current signal sent from the HART device 1 (Step S103 in FIG. 2). The HART / host communication conversion unit 31 regenerates a digital signal (response) from the frequency signal extracted by the HART communication unit 30 (step S104 in FIG. 2).

[0021] The communication interface unit 33 transmits the response passed from the HART / host communication conversion unit 31 via the data management unit 32 to the host device 5 (Step S105 in FIG. 2). In this way, a response returned from the HART device 1 to the command can be transmitted to the host device 5.

[0022] 2, the operation of the HART modem 3 relaying communication between the host device 5 and the HART device 1 is described, but in this embodiment, it is also possible for the data management unit 32 to generate a diagnostic command as described later. When a diagnostic command is to be transmitted to the HART device 1, the processes of steps S101 to S104 are carried out. The communication interface unit 33 may perform wired communication with the diagnostic device 2 or the host device 5, or may perform wireless communication.

[0023] Furthermore, when the designation unit 23 of the diagnostic device 2 receives designation of the communication to be permitted to the HART modem 3 from the user, the designation unit 23 may transmit a communication designation signal designating the communication to be permitted to the HART modem 3. The communication designation signal includes information such as, for example, that only a specific command can be transmitted, that only command transmission is not permitted, or that neither command transmission nor command transmission is permitted.

[0024] When the data management unit 32 of the HART modem 3 receives a communication designation signal via the communication interface unit 33, it permits the execution of the process in FIG. 2 only for the types of communication permitted by the communication designation signal.

[0025] Next, the operation of this embodiment other than the communication function will be described. Fig. 3 is a flow chart for explaining the signal waveform display function of the HART modem 3, and Fig. 4 is a flow chart for explaining the signal waveform display function of the diagnostic device 2.

[0026] The communication waveform detection unit 34 of the HART modem 3 extracts the frequency signal superimposed on the 4 to 20 mA current signal on the analog signal lines 10 and 11, and generates digital data by A / D converting the frequency signal at a constant sampling period (FIG. 3, step S200).

[0027] The data management unit 32 passes the digital data generated by the communication waveform detection unit 34 to the communication interface unit 33. The communication interface unit 33 transmits the digital data received from the data management unit 32 to the diagnostic device 2 (Step S201 in FIG. 3). It goes without saying that the digital data generated by the communication waveform detector 34 may be temporarily stored in the storage medium 40 or another storage medium before being transmitted.

[0028] When the communication waveform generating unit 25 of the diagnostic device 2 receives digital data from the HART modem 3 via the communication interface unit 20 (YES in step S300 in FIG. 4), it generates an image for displaying the signal waveform indicated by the received digital data (step S301 in FIG. 4). The display unit 21 of the diagnostic device 2 displays the image generated by the communication waveform generating unit 25 (FIG. 4, step S302).

[0029] In this way, the signal waveform of the HART communication can be displayed on the diagnostic device 2, and the status of the HART communication can be easily investigated using simple equipment such as the HART modem 3 and the diagnostic device 2.

[0030] 3 and 4 are started in response to a waveform display start instruction signal output from the operation unit 24 operated by, for example, a user of the diagnostic device 2. The waveform display start instruction signal is transmitted to the HART modem 3 via the communication interface unit 20.

[0031] 3 and 4 are stopped, for example, in response to a waveform display stop instruction signal output from the operation unit 24 operated by the user of the diagnostic device 2. The waveform display stop instruction signal is transmitted to the HART modem 3 via the communication interface unit 20. Since the processes of steps S200 and S201 are repeatedly executed until stopped in response to the waveform display stop instruction signal (YES in step S202 in FIG. 3), it goes without saying that the signal waveform displayed by the diagnostic device 2 is updated over time.

[0032] In addition, in the above example, the signal waveform of the HART communication is displayed, but it goes without saying that if the processing of Figures 3 and 4 is started when HART communication is not taking place, the waveform of the noise superimposed on the 4 to 20 mA current signal on the analog signal lines 10 and 11 can be displayed.

[0033] Furthermore, when the designation unit 23 of the diagnostic device 2 receives designation of a device to be connected from a user, the designation unit 23 may transmit a device designation signal for designating the device to be connected to the HART modem 3. The designation unit 23 stores in advance identification information of various devices to be connected to the HART modem 3. The device designation signal transmitted by the designation unit 23 includes the identification information of the device designated by the user.

[0034] When the connection target management unit 38 of the HART modem 3 receives the device designation signal via the communication interface unit 33, it permits execution of the processes in Figures 3 and 4 only for the HART device 1 specified in the device designation signal, and does not permit execution for any HART device 1 not specified in the device designation signal. Note that identification information for the HART device 1 can be acquired through HART communication with the HART device 1. This information makes it possible to determine whether the HART device 1 connected to the HART modem 3 is the device specified in the device designation signal.

[0035] FIG. 5 is a flowchart for explaining the communication protocol analysis function of the HART modem 3, and FIG. As described in step S100, when the data management unit 32 of the HART modem 3 receives a command from the host device 5 (YES in step S400 in FIG. 5), the data management unit 32 transmits the received command to the diagnostic device 2 via the communication interface unit 33 (step S401 in FIG. 5).

[0036] When the communication protocol analysis unit 22 of the diagnostic device 2 receives a command from the HART modem 3 via the communication interface unit 20 (YES in step S500 in FIG. 6), it converts the received command into a hexadecimal value, which is a character string that can be understood by humans (step S501 in FIG. 6).

[0037] The display unit 21 of the diagnostic device 2 displays the hexadecimal value obtained by the communication protocol analysis unit 22 (step S502 in FIG. 6). Note that although the command is transmitted from the host device 5, the communication protocol analysis in this embodiment is performed independently of the operation of the host device 5, so the command received by the HART modem 3 is sent to the communication protocol analysis unit 22 of the diagnostic device 2.

[0038] Furthermore, as described in step S104, when the response is reproduced by the HART / host communication conversion unit 31 (YES in step S402 in FIG. 5), the data management unit 32 of the HART modem 3 transmits the response to the diagnostic device 2 via the communication interface unit 33 (step S403 in FIG. 5).

[0039] When the communication protocol analysis unit 22 of the diagnostic device 2 receives a response from the HART modem 3 via the communication interface unit 20 (YES in step S500), it converts the received response into a hexadecimal value (step S501 in FIG. 6). Display unit 21 of diagnostic device 2 displays the hexadecimal value obtained by communication protocol analysis unit 22 (step S502).

[0040] In this way, the commands and responses of HART communication can be converted into human-understandable character strings and displayed on the diagnostic device 2. 5 and 6 are started in response to an analysis start instruction signal output from the operation unit 24 operated by, for example, a user of the diagnostic device 2. The analysis start instruction signal is transmitted to the HART modem 3 via the communication interface unit 20.

[0041] 5 and 6 are stopped in response to an analysis stop instruction signal output from the operation unit 24 operated by the user of the diagnostic device 2. The analysis stop instruction signal is transmitted to the HART modem 3 via the communication interface unit 20.

[0042] In this embodiment, the commands and responses of HART communication are converted into hexadecimal values, but the communication protocol analyzer 22 may convert the commands and responses into decoded character strings that indicate their meanings, making it possible to convert the commands and responses into a format that is easily understandable to humans and display them.

[0043] Similarly to the above, the designation unit 23 of the diagnostic device 2 may transmit a device designation signal to the HART modem 3 when a connection target device is designated by the user.

[0044] When the connection target management unit 38 of the HART modem 3 receives a device designation signal via the communication interface unit 33, it permits execution of the processes in Figures 5 and 6 only for the HART device 1 designated in the device designation signal, and does not permit execution for any HART device 1 not designated in the device designation signal.

[0045] FIG. 7 is a flowchart for explaining the communication recording function of the HART modem 3, and FIG. The process of step S600 in FIG. 7 is the same as steps S200 and S201 in FIG.

[0046] The data management unit 32 of the HART modem 3 passes the digital data generated by the communication waveform detection unit 34 to the record management unit 39. The record management unit 39 records the digital data received from the data management unit 32 in a storage medium 40 (step S601 in FIG. 7). The HART modem 3 is provided with a slot 41 for mounting the storage medium 40. An example of the storage medium 40 is an SD card. The storage medium may be something like an SSD (solid state drive) that is not intended to be removable.

[0047] On the other hand, the processes in steps S604 and S605 in FIG. 7 are the same as those in steps S400 and S401 in FIG. The data management unit 32 of the HART modem 3 passes the received command to the record management unit 39. The record management unit 39 records the command received from the data management unit 32 in the storage medium 40 (step S606 in FIG. 7).

[0048] The processes in steps S607 and S608 in FIG. 7 are the same as those in steps S402 and S403 in FIG. The data management unit 32 of the HART modem 3 passes the response reproduced by the HART / host communication conversion unit 31 to the record management unit 39. The record management unit 39 records the response received from the data management unit 32 in the storage medium 40 (step S609 in FIG. 7).

[0049] On the other hand, when a command or a response is transmitted from the HART modem 3 to the diagnostic device 2, the communication protocol analyzer 22 of the diagnostic device 2 converts the command or the response received from the HART modem 3 via the communication interface unit 20 into a hexadecimal value (steps S700 and S701 in FIG. 8). The communication interface unit 20 of the diagnostic device 2 transmits the hexadecimal value obtained by the communication protocol analysis unit 22 to the HART modem 3 (Step S702 in FIG. 8).

[0050] When the data management unit 32 of the HART modem 3 receives the hexadecimal value from the diagnostic device 2 via the communication interface unit 33 (YES in step S610 in FIG. 7), it passes the received hexadecimal value to the record management unit 39. The record management unit 39 records the hexadecimal value received from the data management unit 32 in the storage medium 40 (step S611 in FIG. 7).

[0051] In this way, the signal waveform data of HART communication, the commands and responses, and the hexadecimal values ​​of the commands and responses can be recorded in storage medium 40. Storage medium 40 can be removed from HART modem 3 and attached to another device, and the information recorded in storage medium 40 can be confirmed on that other device.

[0052] 7 and 8 are started in response to a recording start instruction signal output from operation unit 24 operated by a user of diagnostic device 2. The recording start instruction signal is transmitted to HART modem 3 via communication interface unit 20.

[0053] 7 and 8 are stopped in response to a recording stop instruction signal output from the operation unit 24 operated by the user of the diagnostic device 2. The recording stop instruction signal is transmitted to the HART modem 3 via the communication interface unit 20.

[0054] As with the communication protocol analysis function, the communication protocol analyzer 22 of the diagnostic device 2 may convert the commands and responses into decoded character strings indicating their meanings, in addition to converting the commands and responses into hexadecimal values. This allows the character strings indicating the contents of the commands and responses to be transmitted from the diagnostic device 2 to the HART modem 3 and recorded in the storage medium 40.

[0055] In this embodiment, at least one type of information among (I) signal waveform data, (II) commands and responses, (III) hexadecimal values ​​of the commands and responses, and (IV) character strings indicating the contents of the commands and responses, may be recorded in the storage medium 40.

[0056] Similarly to the above, the designation unit 23 of the diagnostic device 2 may transmit a device designation signal to the HART modem 3 when a connection target device is designated by the user.

[0057] When the connection target management unit 38 of the HART modem 3 receives a device designation signal via the communication interface unit 33, it permits execution of the processes in Figures 7 and 8 only for the HART device 1 designated in the device designation signal, and does not permit execution for any HART device 1 not designated in the device designation signal.

[0058] In addition, in this embodiment, an example is described in which the signal waveform display function described in Figures 3 and 4 and the communication recording function described in Figures 7 and 8 are performed separately, but it is also possible to record the signal waveform data in the storage medium 40 at the same time as the signal waveform is displayed.

[0059] In addition, in this embodiment, an example is described in which the communication protocol analysis function described in Figures 5 and 6 and the communication recording function described in Figures 7 and 8 are performed separately, but at least one type of information among (II) to (IV) may be recorded in the storage medium 40 at the same time as the communication protocol analysis result is displayed.

[0060] Furthermore, the record management unit 39 of the HART modem 3 may record the identification information of the HART device 1 together with at least one of (I) to (IV) in the storage medium 40. The identification information of the HART device 1 can be acquired by HART communication with the HART device 1.

[0061] FIG. 9 is a flowchart for explaining the wave height measurement function of the HART modem 3, and FIG. The communication waveform detector 34 of the HART modem 3 extracts the frequency signal superimposed on the 4 to 20 mA current signal on the analog signal lines 10 and 11, and measures the peak value of the frequency signal (Step S800 in FIG. 9).

[0062] The data management unit 32 passes the measurement result of the peak value by the communication waveform detection unit 34 to the communication interface unit 33. The communication interface unit 33 transmits the measurement result received from the data management unit 32 to the diagnostic device 2 (step S801 in FIG. 9).

[0063] When display unit 21 of diagnostic device 2 receives the measurement result of the peak value from HART modem 3 via communication interface unit 20 (YES in step S900 in FIG. 10), it displays the received measurement result (step S901 in FIG. 10). In this way, the peak value of the signal waveform of the HART communication can be confirmed by the diagnostic device 2, and it can be confirmed whether the load resistance of the analog signal lines 10, 11 is appropriate or not.

[0064] 9 and 10 are started in response to a measurement start instruction signal output from the operation unit 24 operated by, for example, a user of the diagnostic device 2. The measurement start instruction signal is transmitted to the HART modem 3 via the communication interface unit 20.

[0065] 9 and 10 are stopped in response to a measurement stop instruction signal output from the operation unit 24 operated by the user of the diagnostic device 2. The measurement stop instruction signal is transmitted to the HART modem 3 via the communication interface unit 20.

[0066] In this embodiment, the measurement results of the peak value are transmitted to the diagnostic device 2, but this is not limited to this, and the data management unit 32 of the HART modem 3 may be configured to display the measurement results on the status display unit 37.

[0067] FIG. 11 is a flow chart for explaining the communication status diagnostic function of the HART modem 3, and FIG. The data management unit 32 of the HART modem 3 measures the number of no responses, which is the number of times that a response has not been received from the HART device 1 within a specified time from the time a command was transmitted to the HART device 1 (step S1000 in FIG. 11).

[0068] The data management unit 32 passes the measurement result of the number of no responses to the communication interface unit 33. The communication interface unit 33 transmits the measurement result received from the data management unit 32 to the diagnostic device 2 (Step S1001 in FIG. 11).

[0069] When display unit 21 of diagnostic device 2 receives the measurement result of the number of no responses from HART modem 3 via communication interface unit 20 (YES in step S1100 in FIG. 12), it displays the received measurement result (step S1101 in FIG. 12). In this way, the number of no responses can be confirmed by the diagnostic device 2, and the communication state of the HART communication can be diagnosed.

[0070] 11 and 12 are started in response to a communication status diagnosis start instruction signal output from, for example, the operation unit 24 operated by a user of the diagnostic device 2. The communication status diagnosis start instruction signal is transmitted to the HART modem 3 via the communication interface unit 20.

[0071] 11 and 12 are stopped, for example, in response to a communication status diagnosis stop instruction signal output from the operation unit 24 operated by the user of the diagnostic device 2. The communication status diagnosis stop instruction signal is transmitted to the HART modem 3 via the communication interface unit 20. Since the processes of steps S1000 and S1001 are repeatedly executed until the process is stopped in response to the communication status diagnosis stop instruction signal (YES in step S1002 in FIG. 11), it goes without saying that the number of no responses is updated over time.

[0072] Instead of the number of no responses, the data management unit 32 may measure the ratio N / M (no response ratio) of the total number N of times a response could not be received within a specified time from the transmission of each command to the total number M of commands transmitted from the HART modem 3 to the HART device 1. This makes it possible to transmit the no response ratio to the diagnostic device 2 and display it.

[0073] Similarly to the above, the designation unit 23 of the diagnostic device 2 may transmit a device designation signal to the HART modem 3 when a connection target device is designated by the user.

[0074] When the connection target management unit 38 of the HART modem 3 receives a device designation signal via the communication interface unit 33, it permits the execution of the processing of Figures 11 and 12 only for the HART device 1 specified in the device designation signal, and does not permit execution for HART devices 1 not specified in the device designation signal (they are not subject to measurement of the number of no responses and the no response ratio).

[0075] In this embodiment, the measurement results of the no-response count or no-response ratio are transmitted to the diagnostic device 2, but this is not limited to this, and the data management unit 32 of the HART modem 3 may be configured to display the measurement results on the status display unit 37.

[0076] FIG. 13 is a flow chart for explaining the power supply status diagnosis function of the HART modem 3, and FIG. The power supply state confirmation unit 36 ​​of the HART modem 3 measures the DC voltage between the analog signal lines 10 and 11 (step S1200 in FIG. 13).

[0077] The data management unit 32 passes the measurement result of the DC voltage by the power supply state confirmation unit 36 ​​to the communication interface unit 33. The communication interface unit 33 transmits the measurement result received from the data management unit 32 to the diagnostic device 2 (Step S1201 in FIG. 12).

[0078] When display unit 21 of diagnostic device 2 receives the measurement result of the DC voltage from HART modem 3 via communication interface unit 20 (YES in step S1300 in FIG. 14), it displays the received measurement result (step S1301 in FIG. 14). In this way, the DC voltage between the analog signal lines 10 and 11 can be confirmed by the diagnostic device 2, and the power supply state of the analog signal lines 10 and 11 can be confirmed.

[0079] 13 and 14 are started in response to a power supply status diagnosis start instruction signal output from operation unit 24 operated by a user of diagnostic device 2. The power supply status diagnosis start instruction signal is transmitted to HART modem 3 via communication interface unit 20.

[0080] 13 and 14 are stopped in response to a power supply status diagnosis stop instruction signal output from the operation unit 24 operated by the user of the diagnostic device 2. The power supply status diagnosis stop instruction signal is transmitted to the HART modem 3 via the communication interface unit 20.

[0081] In this embodiment, the measurement result of the DC voltage between the analog signal lines 10 and 11 is transmitted to the diagnostic device 2, but this is not limited to this, and the data management unit 32 of the HART modem 3 may be configured to display the measurement result on the status display unit 37.

[0082] FIG. 15 is a flow chart for explaining the determination function of the HART modem 3, and FIG. When the measurement results of the peak value, the number of no responses or the no response ratio, and the DC voltage are obtained, the judgment unit 43 of the HART modem 3 refers to the knowledge database 42 to judge whether the measurement results conform to the HART protocol specifications and whether the measurement results are consistent with knowledge of past HART communication diagnosis (FIG. 15, step S1400).

[0083] The knowledge database 42 stores in advance information on the HART protocol specifications, knowledge of past HART communication diagnosis, and information on how to deal with cases where the measurement results do not conform to the HART protocol specifications or are inconsistent with the knowledge of past HART communication diagnosis.

[0084] Data management section 32 passes the determination result of determination section 43 to communication interface section 33. Communication interface section 33 transmits the determination result received from data management section 32 to diagnostic device 2 (step S1401 in FIG. 15).

[0085] When the display unit 21 of the diagnostic device 2 receives the determination result from the HART modem 3 via the communication interface unit 20 (YES in step S1500 in FIG. 16), it displays the received determination result (step S1501 in FIG. 16). In this way, the diagnostic device 2 can check whether the measurement results comply with the HART protocol specifications and whether they are consistent with past knowledge of HART communication diagnostics.

[0086] In addition, when the measurement results do not comply with the HART protocol specifications or are inconsistent with knowledge of past HART communication diagnosis (YES in step S1402 of FIG. 15), the instruction unit 44 of the HART modem 3 refers to the knowledge database 42 and obtains information on how to deal with the inconsistency with the HART protocol specifications or the inconsistency with past knowledge from the knowledge database 42 (step S1403 of FIG. 15).

[0087] The data management unit 32 passes the information on the countermeasure acquired by the instruction unit 44 to the communication interface unit 33. The communication interface unit 33 transmits the information on the countermeasure received from the data management unit 32 to the diagnostic device 2 (Step S1404 in FIG. 15).

[0088] When the display unit 21 of the diagnostic device 2 receives the information on the countermeasure from the HART modem 3 via the communication interface unit 20 (YES in step S1502 in FIG. 16), it displays the received information on the countermeasure (step S1503 in FIG. 16).

[0089] In this way, when the measurement results do not comply with the HART protocol specifications or when the measurement results are not consistent with knowledge of past HART communication diagnosis, the diagnostic device 2 can confirm how to deal with the situation.

[0090] 15 and 16 are started in response to a judgment start instruction signal output from the operation unit 24 operated by the user of the diagnostic device 2. The judgment start instruction signal is transmitted to the HART modem 3 via the communication interface unit 20.

[0091] 15 and 16 are stopped in response to a determination stop instruction signal output from the operation unit 24 operated by the user of the diagnostic device 2. The determination stop instruction signal is transmitted to the HART modem 3 via the communication interface unit 20.

[0092] 2 illustrates the operation of the HART modem 3 relaying communication between the host device 5 and the HART device 1, but the data management unit 32 of this embodiment can also generate diagnostic commands. For example, when the data management unit 32 receives a waveform display start instruction signal, an analysis start instruction signal, a recording start instruction signal, a measurement start instruction signal, a communication status diagnosis start instruction signal, or a power supply status diagnosis start instruction signal from the diagnostic device 2, the data management unit 32 may generate a diagnostic command and pass it to the HART / host communication conversion unit 31. This diagnostic command is transmitted to the HART device 1 and the diagnostic device 2 in the same way as the command from the host device 5.

[0093] Of the configuration of the HART modem 3 described in this embodiment, the software functions of the HART communication unit 30, the HART / host communication conversion unit 31, the data management unit 32, the communication interface unit 33, the communication waveform detection unit 34, the power supply status confirmation unit 36, the connection target management unit 38, and the record management unit 39 can be realized by a computer equipped with a CPU (Central Processing Unit), a storage device, and an interface, and a program that controls these hardware resources. An example of the configuration of this computer is shown in Fig. 17.

[0094] The computer includes a CPU 200, a storage device 201, and an interface device (hereinafter abbreviated as I / F) 202. The I / F 202 is connected to the hardware of the HART communication unit 30, the hardware of the communication interface unit 33, the hardware of the communication waveform detection unit 34, the hardware of the power supply status confirmation unit 36, the status display unit 37, the hardware of the record management unit 39, and the like. In such a computer, a program for realizing the diagnostic method of the present invention is stored in the storage device 201. The CPU 200 executes the processing described in this embodiment in accordance with the program stored in the storage device 201.

[0095] Similarly, among the components of the diagnostic device 2, the software functions of the communication interface unit 20, the display unit 21, the communication protocol analysis unit 22, the designation unit 23, the operation unit 24, and the communication waveform generation unit 25 can be realized by a computer. The hardware of the communication interface unit 20, the display, etc. are connected to the I / F 202 of this computer. The CPU 200 of the diagnostic device 2 executes the processes described in this embodiment according to the programs stored in the storage device 201. [Industrial Applicability]

[0096] The present invention can be applied to HART communication. [Explanation of symbols]

[0097] 1...HART device, 2...diagnostic device, 3...HART modem, 5...host device, 20, 33...communication interface section, 21...display section, 22...communication protocol analysis section, 23...designation section, 24...operation section, 25...communication waveform generation section, 30...HART communication section, 31...HART / host communication conversion section, 32...data management section, 34...communication waveform detection section, 36...power supply status confirmation section, 37...status display section, 38...connection target management section, 39...record management section, 40...storage medium, 41...slot, 42...knowledge database, 43...determination section, 44...instruction section.

Claims

1. A diagnostic device; a HART modem for relaying communication between the field device and a host device or the diagnostic device; The HART modem includes: a communication converter configured to relay communication between the field device and the host device or the diagnostic device; a first communication interface configured to transmit a HART communication command transmitted to the field device and a response received from the field device to the diagnostic device; The diagnostic device comprises: a second communication interface configured to receive commands and responses transmitted from the HART modem; a communication protocol analyzer configured to convert received commands and responses into character strings representing the contents of the commands and responses; a display unit configured to display the character string obtained by the communication protocol analysis unit.

2. A diagnostic device; a HART modem for relaying communication between the field device and a host device or the diagnostic device; The HART modem includes: a communication converter configured to relay communication between the field device and the host device or the diagnostic device; a first communication interface configured to transmit a HART communication command transmitted to the field device and a response received from the field device to the diagnostic device, and to receive a character string transmitted from the diagnostic device; a record management unit configured to record the received character string in a storage medium attached to the HART modem; The diagnostic device comprises: a communication protocol analyzer configured to convert commands and responses transmitted from the HART modem into the character strings indicating the contents of the commands and responses; and a second communication interface unit configured to receive commands and responses sent from the HART modem and to send a character string obtained by the communication protocol analysis unit to the HART modem.

Images