JP2013186709A - Diagnostic device and diagnostic method of multi-cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To confirm presence or absence of a cross talk between channels in a multi-cable.SOLUTION: In a non-communication state between an input/output unit and a plurality of devices, a diagnostic method comprises: a process for transmitting a signal to a device connected to a first cable through the first cable forming multi-cable; a process for diagnosing that the signal transmitted to the first cable is interfering in a second cable when a signal is received through the second cable different from the first cable.

Description

  One embodiment of the present invention relates to a technique for diagnosing the presence or absence of signal interference in a multi-cable in which a plurality of cables are grouped.

  At the site where production processes are managed, various field devices (for example, sensors and valves) having a transmission function are installed in the plant, and various production processes are managed by incorporating signals transmitted from the field devices into the system. ing. As a system for managing a production process, for example, there is a system that controls the opening degree of a valve or the like based on a flow rate, temperature, pressure, or the like acquired from a sensor.

  In recent years, field devices and input / output (IO) units connected to such a process management system have been equipped with a HART (Highway Addressable Remote Transducer) (registered trademark) communication function. Some I / O modules support a plurality of channels (for example, 16 channels) and can simultaneously communicate with a plurality of field devices. For connection between the I / O module and a plurality of field devices, a multi-cable in which a plurality of cables are collected may be used.

JP 2003-186503 A Japanese Patent No. 4129715

  When a multi-cable is used to connect an I / O module and a plurality of field devices, there is a possibility that signal interference (crosstalk) occurs between a plurality of cables in the multi-cable (in other words, between channels). is there.

  One of the causes of occurrence of crosstalk is a capacitance component determined by, for example, the capacitance (pF / m) per cable unit length (m), the cable length, and the dielectric constant of the insulation coating of individual cables in a multi-cable. For example, since the dielectric constant of vinyl chloride is higher than that of polyethylene, the use of vinyl chloride for the insulation coating of the individual cable results in a larger capacity component than when polyethylene is used. Therefore, crosstalk between channels is likely to occur. When crosstalk occurs, the normality of communication may be hindered.

  In the case of a new facility, crosstalk can be prevented or minimized by limiting the cable length of the multi-cable to be used or by selecting a cable using an insulation coating with a lower dielectric constant. However, when adding or expanding the HART communication function to the existing equipment, the existing multi-cable may be used as it is. In that case, the presence or absence of crosstalk cannot be confirmed without actually using (communication).

  One of the objects of the present invention is to enable easy confirmation of the presence or absence of inter-channel crosstalk in a multi-cable.

  In addition, the present invention is not limited to the above-described object, and other effects of the present invention can be achieved by the functions and effects derived from the respective configurations shown in the embodiments for carrying out the invention which will be described later. It can be positioned as one of

  One aspect of the multi-cable diagnostic apparatus of the present invention is a multi-cable in which a plurality of devices, an input / output unit, and a plurality of cables that connect each of the plurality of devices to the input / output unit are connected. In the non-communication state between the plurality of devices and the input / output unit, the multi-cable diagnostic device is used in a system including: the first cable through the first cable that forms the multi-cable. When a signal is received through a transmission unit that transmits a signal to a device connected to the cable and a second cable different from the first cable, the signal transmitted to the first cable is transmitted to the second cable. A diagnosis control unit that diagnoses that the cable is interfering with the cable.

  Here, the transmission unit repeats the transmission in a predetermined order with a predetermined period for all of the cables constituting the multi-cable, the diagnosis control unit monitors the presence or absence of the reception in each of the predetermined period, It is good as well.

  The input / output unit includes a signal demodulator corresponding to each of the plurality of cables, and the diagnosis controller determines whether the demodulator corresponding to the second cable is operating. The presence / absence of the reception may be monitored by monitoring.

  For example, the diagnosis control unit may determine that the demodulation unit is operating when a carrier detection signal of the demodulation unit is received.

  In addition, when the diagnosis control unit diagnoses that interference with the second cable has occurred, (1) control for reducing the reception sensitivity of the carrier detection signal of the demodulation unit corresponding to the second cable, (2) at least control for increasing the number of transmissions of the signal addressed to the device corresponding to the second cable, and (3) control for extending the transmission period of the signal addressed to the device corresponding to the second cable. Either one may be implemented.

  Further, the input / output unit may be a unit capable of HART communication with the device in parallel through the multi-cable.

  The system further includes a device monitoring unit that is communicably connected to the input / output unit and that monitors the state of the device through the input / output unit, and the transmission unit is provided in the input / output unit. The unit may autonomously execute the repetition of the transmission in response to a request from the device monitoring unit.

  Next, according to one aspect of the multi-cable diagnosis method of the present invention, a plurality of devices, an input / output unit, and a plurality of cables that connect each of the plurality of devices to the input / output unit are integrated. A multi-cable diagnosis method used in a system comprising: a multi-cable, wherein the plurality of devices and the input / output unit are in a non-communication state through the first cable forming the multi-cable. When the signal transmitted to the device connected to the first cable is received through a second cable different from the first cable, the signal transmitted to the first cable is transmitted to the first cable. A process of diagnosing interference with the two cables.

It is a figure which shows an example of the process management system which concerns on one Embodiment. FIG. 2 is a block diagram illustrating a configuration example of an input / output unit compatible with HART communication illustrated in FIG. 1. FIG. 3 is a block diagram illustrating a configuration example of a smart communication (HART communication) processing unit illustrated in FIG. 2. It is a figure explaining the communication sequence at the time of the normal in the multi-cable which concerns on one Embodiment. It is a figure explaining the communication sequence at the time of abnormality in the multi-cable which concerns on one Embodiment. It is a figure explaining the communication sequence at the time of abnormality in the multi-cable which concerns on one Embodiment. It is a figure which illustrates the communication signal waveform at the time of normal in a multi-cable. It is a figure which illustrates a mode that the interference (crosstalk) between channels generate | occur | produced in the multi-cable. It is a figure for demonstrating one of the generation | occurrence | production factors of the crosstalk between channels.

  Embodiments of the present invention will be described below with reference to the drawings. However, the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described below. In other words, the present invention can be implemented with various modifications (combining the embodiments, etc.) without departing from the spirit of the present invention. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. The drawings are schematic and do not necessarily match actual dimensions and ratios. In some cases, the dimensional relationships and ratios may be different between the drawings.

[1] Description of one embodiment (System configuration)
FIG. 1 is a diagram illustrating an example of a process management system according to an embodiment. The process management system 1 illustrated in FIG. 1 exemplarily includes one or a plurality of field devices 10 that support smart communication, or one or a plurality of fields that do not support smart communication but support other types of communication. A device 12 is provided. “Field device” is an example of “device”.

  An example of “smart communication” is HART communication conforming to the HART (registered trademark) communication protocol or fieldbus communication conforming to the fieldbus communication protocol. An example of “other types of communication” is communication of a proprietary standard such as Xbus described later. HART communication, fieldbus communication, and proprietary communication are all examples of digital communication.

  Examples of the field devices 10 and 12 include a transmitter and a positioner (actuator). An example of the transmitter is various sensors such as a flow rate sensor, a pressure sensor, and a temperature sensor. An example of a positioner converts an electrical signal into a signal corresponding to, for example, an air pressure for control purposes, and performs position control of valves such as a flow rate control valve and a pressure control valve according to the signal.

  The process management system 1 also includes one or more input / output (IO) units (hereinafter referred to as “HART-IO”) 11 that are compatible with HART communication, and one or more inputs that are not compatible with HART communication. An output (IO) unit 13, a device monitoring unit 15, a link module 15A, a controller 17, a driving operation unit 19, and the like can be provided.

  In general, the driving operation unit 19 can communicate with the field devices 10 and 12 via the controller 17 and the IO units 11 and 13, respectively. Through the communication, the driving operation unit 19 can acquire the measured values of the field devices 10 and 12, and can give the setting values and the control values to the field devices 10 and 12 based on the measured values. In other words, the controller 17 and the driving operation unit 19 form an example of a control system that controls the process through the first communication path that passes through the IO units 11 and 13.

  On the other hand, the device monitoring unit 15 can communicate with the field device 10 compatible with HART communication, for example, via the HART-IO 11. Through the communication, the device monitoring unit 15 can obtain information (for example, process information, failure information, etc.) indicating the state of the field device 10, for example. In other words, the device monitoring unit 15 indicates the state of the field device 10 that supports HART communication (hereinafter may be referred to as “HART communication-compatible device”) 10 through the second communication path via the HART-IO 11. An example of a monitoring system to be monitored.

  The device monitoring unit 15 communicates with the field device 10 through the TCP / UDP communication path 16 and the HART-IO 11, and diagnoses the presence or absence of inter-channel crosstalk in the connection between the HART-IO 11 and the field device 10. It has a function as a “talk diagnosis control unit” 151. The inter-channel crosstalk diagnosis control unit (hereinafter, also simply referred to as “diagnosis control unit”) 151 may be provided in the link module 15A or in the IO unit 11 (for example, a first control unit 21 described later with reference to FIG. 3). ).

  The HART-IO 11, the device monitoring unit 15, the link module 15 </ b> A, the controller 17, and the driving operation unit 19 can be connected to a predetermined communication path 16. An example of the communication path 16 is a TCP / UDP communication path capable of digital communication compliant with TCP (Transmission Control Protocol) or UDP (User Datagram Protocol).

  An example of the TCP / UDP communication path (digital communication path) 16 is an Ethernet (registered trademark) communication path (cable). Therefore, the operation unit 19 can perform TCP / UDP communication with, for example, the device monitoring unit 15 and the controller 17, and the device monitoring unit 15 can communicate with the link module 15 </ b> A, the IO unit 11, and the like with TCP / UDP communication (for example, Ethernet communication) is possible.

  For example, the IO units 11 and 13 can be connected to the controller 17 via a predetermined communication path 18 so as to be able to communicate with each other. An example of the communication path 18 is a proprietary Xbus specializing in the communication functions of the controller 17 and the IO unit 13. Xbus is an example of a digital communication path that enables digital communication between the controller 17 and the IO unit 13.

  A HART communication-compatible device 10 can be connected to the HART-IO 11. A field device 12 not supporting HART communication can be connected to the IO unit 13 not supporting HART communication. For these connections, an analog transmission line for transmitting an analog DC signal (for example, 4 mA to 20 mA) can be used.

  For the analog transmission line, a multi-cable 14 in which a bundle of a plurality of cables (for example, a total of 50 pairs of 25 pairs for transmission and reception) is collected can be used. When the multi-cable 14 is used, construction costs can be reduced and cable management can be facilitated. In the multi-cable 14, for example, one pair of cables can be considered to correspond to one channel in transmission and reception.

  The analog DC signal is an example of a signal representing a variable corresponding to the field device 10 or the field device 12. Examples of the variable include measured values such as flow rate, pressure, and temperature obtained by the field device 10 such as a flow meter, a pressure gauge, and a thermometer, and control values such as valve openings of pumps and valves.

  Therefore, the field devices (hereinafter also referred to as “devices”) 10 and 12 send analog DC signals having current values (4 to 20 mA) corresponding to the measured values to the IO units (hereinafter also referred to as “IO modules”) 11 and 13. Can be transmitted to the controller 17 via the controller 17, and an analog DC signal having a current value (4 to 20 mA) corresponding to the set value, control value, etc. transmitted from the controller 17 via the IO units 11 and 13 is received. can do.

  Here, the HART-IO 11 and the field device 10 can transmit a signal obtained by superimposing a digital signal on the analog DC signal. In other words, the HART-IO 11 and the field device 10 can perform analog transmission using an analog DC signal (4 to 20 mA) and digital communication using a digital signal.

  The digital signal superimposed on the analog DC signal is, for example, a signal representing various data that can be acquired in the HART communication-compatible device 10. Examples of the various data include information indicating the state of the HART communication-compatible device 10 (for example, process information, information indicating the state of the device 10, and the like). In addition, you may include the measured value of HART communication corresponding apparatus 10, a control value, etc. in various data.

  In the HART communication protocol, a digital signal converted (for example, phase modulated) is superimposed on an analog DC signal of 4 to 20 mA so as to represent digital values 0 and 1 with two types of frequency signals (for example, 1200 Hz and 2200 Hz). To do.

  When the HART-IO 11 (or the field device 10) receives the analog DC signal on which the digital signal is superimposed in this way from the field device 10 (or the HART-IO 11), the received signal is separated into an analog DC signal and a digital signal. To do. Thereby, HART-IO11 (or field device 10) can acquire the value and data which each separated signal shows.

  Next, a configuration example of the HART-IO 11 as described above is shown in FIG. The HART-IO 11 illustrated in FIG. 2 exemplarily includes an interface (IF) 110 that provides connection with the Xbus 18, an arithmetic unit 111, an analog-digital converter (ADC) 112, a digital-analog converter (DAC) 113, A memory 114 and a smart communication (HAR communication) processing unit 115 are provided.

  The smart communication (HART communication) processing unit 115 may be an external unit independent of the IO unit 11. By using an external unit, for example, by connecting the external unit to an existing IO unit 13 that does not support HART communication, the IO unit 13 can be easily adapted to HART communication.

  In general, communication between the controller 17 and the field device 10 via the HART-IO 11 is performed via a route via the IF 110, the arithmetic unit 111, the ADC 112 or the DAC 113, and the HART communication processing unit 115.

  Note that the arithmetic unit 111 stores the digital signal input from the ADC 112 and the digital signal supplied to the DAC 113 in the memory 114. In other words, the memory 114 can store information such as a control value given to the field device 10 and a measurement value acquired from the field device 10.

  In contrast to the communication between the controller 17 (driving operation unit 19) and the field device 10, the communication between the device monitoring unit 15 (or the link module 15A) and the field device 10 via the IO unit 11 is HART communication. This is performed by a route passing through the processing unit 115.

  As shown in FIG. 3, for example, the HART communication processing unit 115 includes a first control unit 21 and second control units 22-1 to 22-n (n is an integer of 2 or more representing the number of channels. For example, n = 16), modulation / demodulation units 23-1 to 23-n, demultiplexing and superposition units 24-1 to 24-n, and channel slots (hereinafter also simply referred to as “slots”) 25-1 to 25 corresponding to n channels. 25-n. Note that the second control unit 22-i (i = 1 to n), the modulation / demodulation unit 23-i, the separation / superimposition unit 24-i, and the slot 25-i need not be particularly distinguished. Are simply referred to as a second control unit 22, a modulation / demodulation unit 23, a separation / superposition unit 24, and a slot 25, respectively.

  The second control unit 22, the modulation / demodulation unit 23, and the separation / superimposition unit 24 are provided for each channel, and these constitute a “HART transmission / reception unit”. In other words, n-channel HART transmission / reception units are connected in parallel to the lower side of the first control unit 21. For example, the HART transmission / reception unit extracts a frequency signal from the HART communication signal received via the slot 25 and transmits a digital signal corresponding to the frequency signal to the first control unit 21. Further, the HART transmission / reception unit superimposes a frequency signal corresponding to the digital signal received from the first control unit 21 on the analog DC signal addressed to the field device 10 and transmits the signal to the slot 25.

  Although not shown, the separation and superimposing unit 24 separates the 4 to 20 mA analog signal into a DC signal and a frequency signal, and generates a 4 to 20 mA analog signal by superimposing the frequency signal on the DC signal. And a superimposing unit. The demultiplexing / superimposing unit 24 transmits / receives a frequency signal to / from the modulation / demodulation unit 23, and transmits a DC signal to the controller 17, which is an example of an external device, through the ADC 112, the arithmetic unit 111, and the IF 110 illustrated in FIG. Can do.

  The modem unit 23 may be physically configured with, for example, a HART modem. The modem unit 23 executes a conversion process between the frequency signal and the digital signal. For example, the conversion process corresponds to a process of converting a digital signal represented by 0 and 1 into a frequency signal represented by a 2200 Hz signal and a 1200 Hz signal. Moreover, the process which converts the frequency signal represented by the signal of 2200 Hz and the signal of 1200 Hz into the digital signal represented by 0 and 1 corresponds.

  The second control unit 22 may be physically configured with a CPU and peripheral devices, for example. The second control unit 22 controls signal transmission / reception performed between the HART transmission / reception unit and the first control unit 21. For example, the second control unit 22 and the modem unit 23 may be connected by a plurality of (for example, four) signal lines (see FIG. 3). The second controller 22 and the first controller 21 may be connected by a dedicated bus (for example, 100 kbps).

  The signal line connecting the second control unit 22 and the modem unit 23 includes an output carrier detection (OCD) signal line indicating that the modem unit 23 is performing a modulation / demodulation operation, and a second control unit. 22, a received data (RXD) line for receiving the HART signal (data) demodulated by the modem 23, a request transmission (RTS) signal line for transmitting a request signal from the second controller 22 to the modem 23, and A transmission data (TXD) line for transmitting a HART signal (data) from the second control unit 22 to the modem unit 23 is included. FIG. 3 shows the above four lines as a representative example only between the second control unit 22-1 and the modem unit 23-1.

  When receiving the carrier detection signal through the OCD signal line, the second control unit 22 recognizes that the corresponding modulation / demodulation unit 23 is reacting (operating), and notifies the first control unit 21 (“OCD detection”). Event notification ”).

  The first control unit 21 may be physically configured with a CPU and peripheral devices, for example. The first control unit 21 controls communication performed through the TCP / UDP communication path 16 with the device monitoring unit 15 (and / or the link module 15A) illustrated in FIG. 2, which is an example of a higher-level device. When the reception of the carrier detection signal is notified from any of the second control units 22, the first control unit 21 confirms that the modulation / demodulation unit 23 of the channel corresponding to the second control unit 22 is operating, for example, The diagnosis control unit 151 of the monitoring unit 15 can be notified.

  An amplifier (not shown) that amplifies the transmission signal between them to a predetermined signal level may be provided between the modem unit 23 and the separation / superimposition unit 24. The amplifier may be a variable gain amplifier. If a variable gain amplifier is used, the input signal level to the modem unit 23 can be adjusted for each channel. Accordingly, the carrier detection sensitivity in the modem unit 23 can be indirectly adjusted for each channel. However, a mechanism that can directly adjust the carrier detection sensitivity may be incorporated in the modem unit 23.

  In the HART communication processing unit 115 configured as described above, for example, HART signals transmitted from various field devices 10 are processed by the HART transmission / reception units provided for each channel, and the processed signals are subjected to the first control. It can be transmitted to the device monitoring unit 15, which is an example of a higher-level device, via the unit 21. As a result, it is possible to execute the processing for a plurality of channels in parallel with the processing in the HART transmission / reception unit requiring processing time. Therefore, it is possible to shorten the processing waiting time by HART communication and reduce the processing delay of the system.

  Here, in a multiplexer that selectively transmits signals of a plurality of channels, the influence of crosstalk between channels does not have to be considered. However, as described above, it is better to consider when processing for a plurality of channels can be executed in parallel. In the multi-cable 14 that connects the HART-IO 11 and the HART communication-compatible device 10, if cross-channel crosstalk occurs, normal communication may be hindered (for example, communication periodicity in a specific channel may be disrupted). It is.

  Examples of cases where normal communication is hindered (when communication is abnormal) include the following two cases.

  (1) One is when the channel affected by the interference is in a communication state, and the interference waveform is superimposed on one or both of the original request and response, and the waveform of the signal collapses to cause frame destruction. It is.

  (2) The other is when the channel affected by the interference is in a non-communication state, and when the carrier detection occurs due to the interference waveform, the modem unit 23 malfunctions, and the original timing (period) in the channel that is the interference source ) Would interfere with signal transmission.

  One of the factors that cause crosstalk between channels is, for example, a capacitance component determined by the capacitance (pF / m) per cable unit length (m), the cable length, and the dielectric constant of the insulation coating of the individual cables forming the multi-cable 14 is there. The capacitance component may include a capacitance between the grounds of the field device 10 (see FIG. 9). That is, if the ground of the field device 10 is common (for example, connected to the same pipe or the like for surge countermeasures, etc.), the signal may sneak to other channels through the common ground.

  FIG. 7 shows an example of a channel signal (voltage) waveform during normal communication, and FIG. 8 schematically illustrates a state in which inter-channel crosstalk has occurred. 7 and 8 illustrate signal (voltage) waveforms for the first channel (ch1) and the second channel (ch2).

  The signal waveform illustrated in FIG. 7 illustrates a state in which communication is performed at a predetermined cycle (for example, 1 second cycle) (a request signal and a response signal are repeatedly transmitted at a predetermined timing, respectively).

  On the other hand, in FIG. 8, the signal of the second channel interferes with the first channel, and the signal of the first channel interferes with the signal of the second channel. As can be seen from FIG. 8, when crosstalk between channels occurs, the original periodicity of communication illustrated in FIG. 7 (for example, communication with a period of 1 second) is disrupted as illustrated in FIG. As a result, the predetermined cycle cannot be maintained, and normal communication may be hindered.

  Note that the example of FIG. 8 is an example in which interference occurs between both channels and the periodicity of communication for both channels is disrupted, but only the periodicity of communication for one channel is disrupted. There is also a case.

  7 and 8, there is a difference in signal waveform amplitude (maximum amplitude) between the first channel (ch1) and the second channel (ch2). This is because different devices 10 are connected to each channel. This is because the reception impedance is different. Therefore, for example, if the same field device 10 is connected to each channel, the amplitude difference of the signal waveform of each channel can be minimized (ideally zero).

  In view of the occurrence of inter-channel crosstalk in the multi-cable 14 as described above, the inter-channel crosstalk diagnostic control unit 151 is used in the present embodiment. That is, the diagnosis control unit 151 is used to diagnose whether or not inter-channel crosstalk occurs in the multi-cable 14 that connects the HART-IO 11 and the HART communication-compatible device 10.

  Hereinafter, a diagnosis procedure by the diagnosis control unit 151 will be described.

  FIG. 4 shows an example of a command (request and response) transmission / reception state at the normal time. Each horizontal axis in FIG. 4 indicates time. FIG. 4A is a chart showing a communication state between the device monitoring unit 15 (or the link module 15A) and the first control unit 21. FIG. 4B is a chart showing the state of Ethernet communication through the TCP / UDP communication path 16.

  FIG. 4C is a chart showing a processing state in the first control unit 21. FIG. 4D is a chart showing a state of communication (interchip communication) between the first control unit 21 and the second control unit 22. FIG. 4E is a chart showing a processing state in the second control unit 22 (for example, the second control unit 22-1). FIG. 4F is a chart showing the HART communication / processing state of “ch1”, for example.

  In FIG. 4, “1” schematically indicates processing for “ch1” (for example, transmission of a request, transmission of a response to the request, etc.). That is, in FIG. 4, the request signal of “ch1” transmitted from the device monitoring unit 15 (or the link module 15A) is the Ethernet communication, the first control unit 21, the inter-chip communication, the second control unit 22-1, A state in which the response signals for the request signals are transmitted to the device monitoring unit 15 (or the link module 15A) in the reverse order is illustrated. Note that the error determination may be performed by the first control unit 21 or the second control unit 22, and only the event and status may be transmitted to the device monitoring unit 15 (or the link module 15A).

  On the other hand, FIGS. 5 and 6 show examples of command transmission / reception states at the time of abnormality. Each horizontal axis of FIG.5 and FIG.6 shows time. FIG. 5A and FIG. 6A are charts showing a communication state between the device monitoring unit 15 (or link module 15A) and the first control unit 21. FIG. FIGS. 5B and 6B are charts showing the state of Ethernet communication through the TCP / UDP communication path 16.

  FIG. 5C and FIG. 6C are charts showing processing states in the first control unit 21. FIGS. 5D and 6D are charts showing a state of communication (interchip communication) between the first control unit 21 and the second control unit 22. FIGS. 5E and 6E are charts showing processing states in the second control unit 22 (for example, the second control unit 22-1 corresponding to “ch1”). FIG. FIG. 6F is a chart showing a processing state in the second control unit 22 corresponding to another channel (for example, the second control unit 22-2 corresponding to “ch2”). FIGS. 5G and 6G are charts showing the HART communication / processing state of “ch1”, for example. FIGS. 5H and 6H are HART communication / processes of “ch2”, for example. It is a chart which shows a processing state.

  Here, “at the time of abnormality” means, for example, a case where a delay or the like occurs in periodic communication as illustrated in FIG. 4. As described above, a channel that receives interference from a certain channel communicates. It can occur when there is no state and when it exists.

  That is, (1) when a channel affected by interference is in a communication state, the interference waveform is superimposed on one or both of the original request and response, and the waveform of the signal collapses to cause frame destruction; (2) When the channel affected by the interference is in a non-communication state, when the carrier detection occurs due to the interference waveform, the modem unit 23 malfunctions, and the signal transmission at the original timing (period) is prevented. There is.

  An example of a communication sequence in the case of (1) is illustrated in FIG. 6, and an example of a communication sequence in the case of (2) is illustrated in FIG.

  First, FIG. 5 will be described. When the second channel is in a non-communication state, as illustrated in FIG. 5 (h), the interference signals 401 and 402 resulting from the request signal and the response signal of the first channel (ch1) are the second channel (ch2). In the HART communication.

  Then, carrier misdetection occurs for each of the interference signals 401 and 402 in the modem unit 23-2 corresponding to the second channel. As a result, a signal (indicated by “2 ′” and “2 ″” in FIG. 5) addressed to the device monitoring unit 15 (or the link module 15A) is erroneously generated and transmitted in the second control unit 22-2. .

  As a result, as illustrated in FIG. 5F to FIG. 5A, a signal erroneously generated for the second channel erroneously generated before the response signal of the first channel is interrupted. Therefore, a delay occurs in the original periodic communication of the first channel, and the predetermined periodicity cannot be maintained (normal communication is hindered).

  On the other hand, for example, as indicated by reference numeral 403 in FIG. 6H, it is assumed that the signal waveform of one or both of the request signal and the response signal of the first channel interferes with the response signal of the second channel in the communication state.

  Then, part or all of the response signal of the second channel (the latter half in the example of FIG. 6H) is destroyed (waveform deformation) (frame destruction). Therefore, for example, as shown in FIG. 6F, a checksum (CS) error or the like (error detection) occurs in the second controller 22-2 corresponding to the second channel, and the response signal (frame) is Judged as an invalid frame.

  As a result of the determination, a retry signal is generated, and the retry signal is addressed to the device monitoring unit 15 (or link module 15A) as illustrated by “2 ′” in FIGS. 6 (f) to 6 (a). Is transmitted. Due to the transmission (interrupt) of the retry signal, a delay occurs in the original periodic communication of the first channel, and the predetermined periodicity cannot be maintained (normal communication is prevented).

In order to confirm the presence / absence of crosstalk between channels that causes a communication abnormality as described above, the following procedure is exemplarily performed in the present embodiment.
(1) First, the HART-IO 11 and the field device 10 are connected by the multi-cable 14.

  (2) The HART-IO 11 (HART communication processing unit 115) is set to the multi-cable diagnosis mode. That is, all HART communication between the HART-IO 11 and each field device 10 is set to a non-communication state.

  (2-1) The diagnosis control unit 151 of the device monitoring unit 15 (or the link module 15A) transmits a diagnosis request command to the HART-IO 11 by, for example, Ethernet communication.

  (2-2) The diagnosis request command is received by the HART communication processing unit 115 (first control unit 21) of the HART-IO 11. When the first control unit 21 receives the diagnosis request command, for example, one of the second control units 22-i for 16 channels (ch1-ch16) (for example, the first control unit 22-1 corresponding to ch1). ) To output a HART signal (request signal) to the field device 10. The first control unit 21 requests the second control unit 22 to stop the HART communication for the remaining channels (for example, ch2-16ch). Thereby, a HART signal is transmitted to the corresponding field device 10 by the HART transmitting / receiving unit corresponding to the second control unit 22-1 (ch1).

  (2-3) Thereafter, the first control unit 21 monitors whether the request signal for ch1 and the response signal from the field device 10 for the request signal interfere with other channels. In the monitoring, for example, a carrier detection signal is generated in the remaining channels 2-16, and whether any of the modulation / demodulation units 23-2 to 23-16 corresponding to the channel is operating (reactive) in advance is determined. It is implemented by monitoring for a fixed period (fixed time). If any of the modems 23-2 to 23-16 is operating during the monitoring period, for example, the first control unit 21 receives a signal other than ch1 (response signal, OCD detection event notification, etc.). , It is confirmed that the signal of ch1 interferes with the corresponding other channel (for example, ch2 as illustrated in FIG. 5).

  (2-4) Next, when the monitoring period elapses, the first controller 21 -the second controller 22-corresponding to a channel (for example, ch 2) different from the second controller 22-1 corresponding to ch 1. 2 is requested to output a HART signal (request signal) to the field device 10. The first control unit 21 requests the second control unit 22 to stop the HART communication for the remaining channels (for example, ch1 and ch3-ch16). Thereby, a HART signal is transmitted to the corresponding field device 10 by the HART transmission / reception unit corresponding to the second control unit 22-2 (ch2).

  (2-5) Thereafter, the first control unit 21 determines whether the request signal for ch2 and the response signal from the field device 10 for the request signal interfere with other ch1 and ch3-ch16 ( Monitor as in 2-3). If any of the modems 23-1 and 23-3 to 23-16 is operating during the monitoring period, for example, the first control unit 21 receives a signal other than ch2 (response signal, OCD detection event notification, etc.). Therefore, it is diagnosed (confirmed) that the ch2 signal interferes with other channels.

  After (2-6), the first control unit 21 confirms the presence or absence of interference by repeating the processes (2-3) to (2-5) for all channels. The confirmation result data is notified from the first control unit 21 to the diagnosis control unit 151. The notification may be performed for each channel or may be performed for a plurality of channels collectively.

  (2-7) If interference occurs, the interference source channel and the channel receiving the interference are specified. The identification may be performed by the diagnosis control unit 151 in the device monitoring unit 15 (or the link module 15A) or by the first control unit 21 in the HART-IO 11 (HART communication processing unit 115), and the result is diagnosed. You may notify to the control part 151. FIG.

  (2-8) The diagnosis control unit 151 presents countermeasures to the user of the device monitoring unit 15, for example, based on the information of the identified interference source channel and the channel receiving the interference.

  In the above-described example, the HART-IO 11 (the first control unit 21 of the HART communication processing unit 115) that has received the diagnosis request command from the device monitoring unit 15 (or the link module 15A) autonomously diagnoses all channels. Have been implemented.

  Therefore, the device monitoring unit 15 (or link module 15A) needs to send a diagnosis request command to the HART-IO 11 only once, so that the processing load of the device monitoring unit 15 (or link module 15A) and TCP / UDP communication The communication load (traffic amount) on the path 16 can be reduced.

  However, this does not exclude sending a diagnosis request command from the device monitoring unit 15 (or the link module 15A) to the HART-IO 11 for each channel.

  As an example of measures when it is diagnosed that interference occurs between any of the channels in the multi-cable 14, the following may be mentioned.

  (A) Replace the cable with a multi-cable that does not cause interference.

  (B) The interference source channel is connected by another twisted cable without using a multi-cable.

  (C) Change the routing in the multi-cable 14 for each channel to find a combination that does not cause interference.

  (D) If a field device that does not use HART communication is included in the system, the device is connected to a channel (slot 25) that is affected by interference. In other words, the HART communication-compatible device is not connected to the channel (slot 25) (connection is limited).

  (E) The probability of occurrence of inter-channel interference is reduced by increasing the number of request signal transmissions (retry times) for a channel affected by interference or by increasing the transmission cycle.

  (F) For example, by mounting a mechanism capable of adjusting (for example, lowering) the carrier detection sensitivity / amplifier gain for each channel as described above, the modulation / demodulation unit 23 operates due to interchannel interference, and the original signal is obtained. Prevents non-conformities in advance.

  (G) In order to prevent interference between channels, an insulator (isolator) or the like is connected to the channel that is the source of interference or the channel that is affected by the interference to cut the coupling between the channels.

  The above measures may be combined appropriately. In addition, measures (e) and (f) are mounted in the HART-IO 11 (for example, the first control unit 21 of the HART communication processing unit 115), and the setting is automatically changed to prevent the interference between channels. You may enable it to select the system configuration which does not produce influence autonomously.

  As described above, according to this embodiment, since the presence or absence of crosstalk between channels in a multi-cable can be easily confirmed, for example, when a HART communication function is added or expanded to an existing facility, a plant is fully operational. Before, the soundness of communication using the multi-cable 14 can be determined.

  In the field (plant), it is difficult to change or reroute the multi-cable 14, and there are cases in which only the person in charge knows how the cables are actually wired. There are many cases that cannot be understood unless they are implemented.

  Even in such a case, the soundness of communication using the multi-cable 14 can be easily confirmed by using the above-described embodiment, so that the work efficiency and cost of facility update at the site can be greatly reduced. There is expected.

DESCRIPTION OF SYMBOLS 1 ... Process management system, 10 ... Field device (HART communication correspondence), 11 ... Input / output (IO) unit (HART-IO), 12 ... Field device (non-HART communication correspondence), 13 ... Input / output (IO) unit ( 14 ... multi-cable, 15 ... device monitoring unit, 15A ... link module, 16 ... TCP / UDP communication path (Ethernet etc.), 17 ... controller, 18 ... communication path (Xbus etc.), 19 ... running Operation unit, 21-1 to 21-n ... first control unit, 22-1 to 22-n ... second control unit, 23-1 to 23-n ... modulation / demodulation unit, 24-1 to 24-n ... separation and superposition , 25-1 to 25-n ... channel slot, 110 ... interface (IF) 110, 111 ... arithmetic unit, 112 ... analog-digital converter (ADC) 113 ... digital - analog converter (DAC), 114 ... memory, 115 ... smart communication (HART communication) processing unit, between 151 ... channel crosstalk diagnosis control unit, 401, 402 ... interference signal

Claims (8)

The multi-cable used in a system comprising a plurality of devices, an input / output unit, and a multi-cable in which a plurality of cables that connect each of the plurality of devices to the input / output unit are connected together. A diagnostic device,
In a non-communication state between the input / output unit and the plurality of devices, a transmission unit that transmits a signal to a device connected to the first cable through the first cable forming the multi-cable;
A diagnostic control unit that diagnoses that a signal transmitted to the first cable is interfering with the second cable when a signal is received through a second cable different from the first cable;
Multi-cable diagnostic device with The transmission unit repeats the transmission in a predetermined order with a predetermined period for all the cables constituting the multi-cable,
The multi-cable diagnosis apparatus according to claim 1, wherein the diagnosis control unit monitors the presence / absence of the reception in each of the predetermined periods. The input / output unit includes a signal demodulator corresponding to each of the plurality of cables,
3. The multi-cable diagnostic apparatus according to claim 1, wherein the diagnosis control unit monitors the presence / absence of reception by monitoring whether the demodulation unit corresponding to the second cable is operating. 4. .   The multi-cable diagnostic apparatus according to claim 3, wherein the diagnosis control unit determines that the demodulation unit is operating when a carrier detection signal of the demodulation unit is received. When the diagnosis control unit diagnoses that interference with the second cable has occurred,
(1) Control for reducing the reception sensitivity of the carrier detection signal of the demodulator corresponding to the second cable;
(2) control to increase the number of transmissions of signals addressed to the device corresponding to the second cable; and
(3) The multi-cable diagnostic apparatus according to claim 4, wherein at least one of control for extending a transmission cycle of a signal addressed to the device corresponding to the second cable is performed.   The multi-cable diagnostic apparatus according to claim 1, wherein the input / output unit is a unit capable of performing HART communication with the device in parallel through the multi-cable. The system further includes a device monitoring unit that is communicably connected to the input / output unit and that monitors the state of the device through the input / output unit.
The transmitter is provided in the input / output unit;
The multi-cable diagnostic apparatus according to claim 2, wherein the transmission unit autonomously executes the repetition of the transmission in response to a request from the device monitoring unit. The multi-cable used in a system comprising a plurality of devices, an input / output unit, and a multi-cable in which a plurality of cables that connect each of the plurality of devices to the input / output unit are connected together. A diagnostic method of
A process of transmitting a signal to a device connected to the first cable through the first cable forming the multi-cable in a non-communication state between the input / output unit and the plurality of devices;
When a signal is received through a second cable different from the first cable, a process of diagnosing that the signal transmitted to the first cable is interfering with the second cable;
A multi-cable diagnostic method.