JP2008283259A - Distributed control system and device controller - Google Patents

Abstract

Disclosed is a distributed control system capable of dealing with differences in performance of optical modules, optical cable wiring lengths, increase / decrease in field devices, etc., by performing correction according to the variation of the received waveform distortion width.
SOLUTION: The communication information is circulated in one direction while passing through a plurality of field devices that exchange communication information with a plurality of field devices that exchange measurement information and control information, and an upper field device that exchanges communication information. In a distributed control system provided with a loop-shaped network control loop having an optical cable transmission path for transmitting, the plurality of field devices include an optical communication interface control circuit for exchanging the communication information with the transmission path. And the optical communication interface control circuit sends out a waveform distortion detection circuit for detecting a waveform distortion width included in the received communication information and a correction corresponding to the waveform distortion width detected by the waveform distortion detection circuit. A waveform distortion correction circuit for supplementing the communication information is included.
[Selection] Figure 1

Description

  The present invention relates to a distributed control system and an apparatus controller using optical communication control.

  In the case of using a device controller that controls on the same board, such as measurement and control, which are a plurality of control objects, a huge number of cables need to be connected between the device controller and the control object.

  The field device is a device that measures a temperature or the like to be controlled and controls a motor or the like.

  A fieldbus refers to a communication system in which a plurality of field devices and a host field device that serves as a master for controlling the entire device system are connected on one type of cable.

  By adopting the field bus, it is possible to reduce the wiring between the field devices, but the method of network connection varies depending on the type and characteristics of the transmission path used for communication.

  Here, as shown in FIG. 1, the network connection using the twisted pair wires is a master field device 1 a and a bus type from a field device 1-b serving as a slave to a field device 1 -n. Interface.

  Since the transmission direction of the optical communication here has directivity, as shown in FIG. 2, a ring shape from the upper field device 2-a and the upper field device 2-a serving as a slave to the upper field device 2-n. Network connection form.

  JP-A-10-261995 (Patent Document 1) will be described as a reference.

  In an optical interface circuit (shown in FIG. 3) using a simple optical module, distortion occurs in the received waveform. In the form of the ring-shaped network connection, distortion of 4 to 8 field devices is accumulated, and the signal level cannot be identified by the receiving circuit of the field device, so the number of connection of field devices is limited. appear.

  As a countermeasure to this, as described in Patent Document 1, the number of connected devices is increased by shortening the reception signal, which is a communication signal of the field device, by a predetermined time and correcting the distortion of the transmission signal, which is the communication signal of the field device. It is possible to make it.

Japanese Patent Publication No. 10-261995

  However, in the device described in Patent Document 1, the performance difference of the simple (cheap model) optical module equipped in the field device, the performance difference in manufacturing the simple (cheap model) optical module, the wiring length of the transmission path of the optical cable Thus, there is a problem that the number of connected devices is limited in a state where distortion occurs in the communication signal.

  In Patent Document 1, when a circuit that corrects distortion by a predetermined time width at the time of network construction is created according to the simple (cheap type) optical module installed in the field device, a plurality of field devices are used. Network construction is possible.

  However, when replacing with field device substitutes due to the life cycle of parts, or adding field devices that occur during device expansion, it is necessary to adjust the circuit to correct the distortion by the predetermined time width again, and some fields It is difficult to replace the device.

  In the form of a ring network connection that employs a simple (cheap type) optical module, if the operating power of one of the field devices is abnormal in the connected field device, the ring network is It cannot be used for parts that are blocked and require reliability.

  In view of the above problems, the present invention can cope with differences in performance of optical modules, wiring lengths of optical cables, increase / decrease in field devices, etc., by performing correction according to the fluctuation amount corresponding to the distortion width of the received waveform. An object is to provide a distributed control system.

  The present invention includes a plurality of field devices that exchange communication information for measurement and control of a control target, an upper field device that exchanges communication information with the plurality of field devices, the plurality of field devices, and the upper field device. In the distributed control system comprising a loop-shaped network control loop having an optical cable transmission path that conveys the communication information so as to circulate in one direction, the plurality of field devices and the upper field device are configured to transmit the transmission information. An optical communication interface control circuit that transfers the communication information to and from the path, and the optical communication interface control circuit includes a waveform distortion detection circuit that detects a waveform distortion width included in the received communication information; The communication information for sending out a correction corresponding to the waveform distortion width detected by the waveform distortion detection circuit Characterized in that it has a waveform distortion correction circuit to compensate.

  The present invention also relates to a device controller included in a field device or a host field device of a distributed control system having a loop-shaped network control loop. The device controller includes a system control MPU, a system control interface circuit, and a main MPU work Storage device including storage memory, non-volatile memory for storing communication abnormality information, interface unit between information processing devices by Ethernet controller, external bus interface unit implemented as interface between control devices, communication control A chip, an optical communication interface control circuit, and a maintenance display having a display function. The optical communication interface control circuit converts an optical signal of an optical signal of received communication information into an electrical signal; The light that converts electrical signals into optical signals A waveform distortion detection circuit that detects distortion included in the received communication information, and a waveform distortion correction circuit that performs correction corresponding to the amount of distortion detected by the waveform distortion detection circuit. It is characterized by.

  According to the present invention, since a correction corresponding to the amount of fluctuation corresponding to the distortion width of the received waveform is performed, a distributed control system that can cope with differences in performance of optical modules, wiring length of optical cables, increase / decrease in field devices, and the like is provided. be able to.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a bus-type control network.

  This control network is a bus type network connection that becomes a master field device 1-a that uses a twisted pair wire and a field device 1-b that becomes a slave to 1-n.

  Since the configuration of the network connection in the optical communication has directivity in the transmission direction of the optical communication signal, as shown in FIG. 2, the master field device 2-a and the slave field devices 2-b to 2 are used. It becomes the structure of the ring-shaped network connection used as -n.

  The host field device 2-a and the field devices 2-b to 2-n are connected by a transmission path of the optical cable 4.

  FIG. 3 shows an example of a device controller.

  The device controller 3 is a controller board incorporated in a master upper field device that manages the entire device and a slave field device.

  The feel device is connected to a control target and controls temperature, a motor, a sensor, and the like. The controller board of the feel device is connected to the control target via the external bus interface 41.

  The system control MPU 39 is connected to the control target to be controlled and the master field device via a ring network, and manages the control target such as the temperature and motor controlled by the slave field device and the configuration of the field device. To do.

  The MPU work main memory 40 is composed of, for example, a plurality of Synchronous DRAMs, and the main memory is mainly used as a program or work storage area for the system control MPU 39 to execute.

  Further, a data correction area at the time of writing to and reading from the MPU work main memory 40 is also included.

  The non-volatile memory 37 is composed of, for example, a plurality of flash memories, and is an area in which a program for the system control MPU 39 to control field devices, a diagnosis function of the device controller, and a communication abnormality history received by the communication control chip 31 are stored. is there.

  The communication abnormality information received by the communication control chip 31 is written to the nonvolatile memory 37 via the system control interface circuit 38, and the history of communication abnormality information is stored.

  The maintenance indicator 32 is, for example, an LED, and the communication control chip 31 or the system control MPU 39 is turned on via the system control interface circuit 38 based on the history of the communication abnormality information stored in the nonvolatile memory 37, and Indicates that a communication error has occurred in the field device.

  Further, at the time of maintenance, it has a maintenance function for visually showing the physical arrangement position of the field device of the communication abnormality information generation source to a service person from a plurality of field devices arranged in the apparatus.

  The communication control chip 31, the optical communication interface control circuit 33, the maintenance display 32, and the battery 34 for power backup are equipped in all field devices connected to the device controller including the slave, and the communication received by the communication control chip. The abnormality information is stored as a history of communication abnormality information in the non-volatile memory 37 of the device controller together with the unique address of the field device serving as a slave via the ring network, and is centrally managed by the device controller.

  The Ethernet controller 36 and the Ethernet driver 35 exchange the history of the communication abnormality information with the information processing device via communication. The information processing device can display the communication abnormality information on the maintenance screen and use the maintenance function via the device controller.

  Note that Ethernet is a registered trademark.

  FIG. 4 shows the configuration of the optical communication interface control circuit 33.

  The optical communication unit of the optical communication interface control circuit 33 includes an optical receiver 334 including an optical module that converts an optical signal into a digital signal and a receiving circuit, and an optical module and a receiving circuit that converts the digital signal into an optical signal. The optical transmitter 332 is provided.

  The optical communication interface control circuit 33 includes a backup circuit 335 that supplies power to the optical communication unit when the power supply of the apparatus controller is cut off, and a waveform distortion detection circuit that detects and holds the distortion width of the received waveform. 333, a waveform distortion correction circuit 331 for correcting the distortion of the transmission waveform by the distortion width received from the waveform distortion detection circuit 333.

  The optical communication interface control circuit 33 shown in FIG. 4 has a function of correcting the distortion of the reception waveform and correcting the transmission waveform as shown in FIG.

  The received waveform causes a delay 51 and a distortion 52 of several tens of nanoseconds due to the influence of a simple (cheap type) optical module.

  Since the transmission path for optical communication is the ring network, the field device converts its own received signal from an optical signal to a digital signal, converts it again into an optical signal and transmits it, excluding its own transmission signal.

  Therefore, the distortion of the simple (inexpensive) optical module is accumulated every time it passes through the field device, and a communication error occurs when the data transition width that can be recognized by the communication chip 31 is exceeded.

  The waveform distortion detection circuit 333 shown in FIG. 4 compares the normal 1-bit waveform width 54 with the actually received 1-bit waveform width 55, and detects the distortion waveform width of the correction 53 shown in FIG.

  The waveform distortion correction circuit 331 has a function of correcting the transmission signal by the amount of distortion received from the waveform distortion detection circuit 333.

  The embodiment of the present invention is equipped with a mechanism for transmitting a waveform in which the waveform distortion of the received signal is corrected to a regular 1-bit waveform width, so that the waveform width can be adjusted regardless of the performance difference of the simple (cheap type) optical module. The structure does not accumulate distortion.

  Conventionally, it has been necessary to create an optical communication interface control circuit for each field device in accordance with the performance of a simple (inexpensive) optical module.

  However, in the embodiment of the present invention, the optical communication interface control circuit 33 can be shared because it is not affected by the performance difference of the simple (cheap) optical module.

  The communication system of the embodiment of the present invention is based on the differential Manchester encoding system, and the H / L state of the communication signal is not maintained more than the normal 1-bit width 54 shown in FIG. This is a communication processing method that does not maintain the level.

  In the embodiment of the present invention, when the bit width is detected by the waveform distortion detection circuit 333 shown in FIG. 4 and a bit width of 2 bits or more of the communication speed is detected, the bit width length abnormality detection 338 is performed.

  This information is stored in the nonvolatile memory 37 as communication abnormality information via the communication control chip shown in FIG.

  The slaves 3-a to 3-n optical communication drivers shown in FIG. 2 have the same function, and the collision detection and transmission path abnormality information obtained from 3-a to 3-n are transmitted via optical communication. Supplied to the master 3.

  Each of the slaves 3-a to 3-n has position information, and the position information, collision detection, and transmission path abnormality information are paired and stored in the nonvolatile memory of the master 3.

  The master 3 performs unified management of communication abnormality information. The transmission identification circuit 336 shown in FIG. 4 prohibits output of the transmission signal from the device controller again on the transmission line when the transmission signal returns around the ring-shaped transmission line. .

  The transmission enable delay circuit 337 has a function of delaying the transmission enable signal controlled by the communication control chip by the time required for the transmission signal to return around the ring-shaped transmission line.

  The backup circuit 335 shown in FIG. 4 has a function of supplying power to the optical communication driver 33 when the power source of the apparatus that is the power supply source is cut off. This function avoids communication failures of field devices connected to the ring-shaped transmission path.

  Since the master field device periodically receives information from the slave field device and does not receive a response from the slave field device, the master field device detects this as an abnormality of the slave device, and executes a device stop procedure.

  As shown in FIG. 6, a simple master / slave configuration between the communication control chip (master) 31 and the communication control chips (slave) 631 to 63n to which the optical communication driver 61 having the same configuration as the optical communication driver 33 is connected. Type repeaters can be created, and if this repeater is used in parts where reliability is required, such as between devices, communication with the device alone can be continued except when the power is turned off. There is also an effect of suppressing reliability and improving reliability.

  Hereinafter, application examples of the present invention will be described as a motor mechanism, an analysis mechanism, and a sample transport mechanism of a medical analyzer as examples.

  In FIG. 7, an apparatus controller and analyzers 761 to 763 are connected by a sample transport line 77, photosensors 721 to 723 for detecting a sample position, motor controllers 731 to 733 for driving a transport system and an analysis system, and analysis data. It comprises analysis controllers 741 to 742 for analysis.

  These field devices are connected by an optical communication cable 77.

  The field device as a master is the device controller 71. The field devices serving as slaves correspond to the photosensors 721 to 723, the motor controllers 731 to 733, and the device controller 71 periodically obtains an abnormal communication state from a plurality of field devices serving as slaves through an optical cable.

  In addition, a repeater 76 is connected between the analysis devices to ensure communication reliability between devices with different power supplies.

  The combinations of the analyzers 761 to 763 are changed depending on the scale of analysis required. In the embodiment of the present invention, even if the configuration is changed, the apparatus controller can cope with a combination of a plurality of analyzers without being conscious of distortion of a communication signal by a ring-shaped transmission line using optical communication.

  The device controller 71 periodically acquires communication abnormality information from the photosensors 712 to 723 and the motor controllers 731 to 733 that are slaves of the field device. The injection mechanism, centrifuge mechanism, reagent temperature management function, etc. can be stopped after they are in a safe state, and an alarm can be displayed on the maintenance screen, ensuring the safety of the specimen, reagent, and mechanism.

  In FIG. 8, the connection between the device controller and the field device will be described.

  A device controller 84, which is a field device master, is connected to field device slaves 85-a to 85-n through an optical cable 83, and a device controller 84 connected to an information processing device 81 through a LAN (Ethernet) is a slave periodically. The field devices 85-a to 85-n have a function of acquiring and storing a communication abnormality state.

  The information processing device 81 acquires communication abnormality state data from the device controller 84 and displays it on the maintenance screen.

  Further, as shown in FIG. 9, the LED 91 indicating the physical positions of the device slaves 85-a to 85-n designated by the service person on the maintenance screen is turned on to improve the maintainability.

  FIG. 10 shows an example of a maintenance screen.

  As shown in FIG. 10, the information processing device is equipped with a maintenance screen.

  It comprises an analysis module selection button 101, field device status displays 103 and 103 mounted in the analysis module, scroll buttons 105 and 106 for the field device, displayed field device history display 107 buttons, and a cancel button 107 for canceling input. Yes.

  The analysis module selection button 101 can select all analysis modules connected to the transport line. The selectable analysis modules are displayed as shown on the screen display 102.

  The status display 103 of the field device mounted on the selected analysis module, the address information of the field device, the control target mechanism, and the date and time when the communication abnormality is detected can be displayed.

  When the history display check button 104 is checked and the history display button is operated, it is possible to switch to the detailed display of the field device.

  As shown in FIG. 11, the detailed display of the field device is switched by the history display button.

  The detailed display 11 includes a date and time history display 111 on which a communication error has occurred, up and down scroll buttons 112 and 113 of the history display 111, a position display 115 of the field device in the apparatus, and a cancel button 118 for returning to the previous state. To do.

  The position display 115 is equipped with field device position information 114 for the device external view 116 and the device external view 116. The position information display button 117 turns on an LED indicating the physical position of the field device arranged in the apparatus.

  In the apparatus, a plurality of field devices are mixed and mounted.

  The service person can easily and reliably recognize the position and abnormal state of the field device by operating this maintenance screen. Further, the remote maintenance can be facilitated by connecting the information processing device to the local network.

The figure which shows the bus-type control network using a twisted anti-gland. A ring-type control network using optical communication. The figure which shows the block circuit of an apparatus controller. The figure which shows an optical communication interface control circuit (optical communication driver). The figure which shows waveform distortion correction. The figure which shows the repeater using optical communication. The figure which shows a medical sample conveyance apparatus. The figure which shows the connection of an apparatus controller and a field apparatus. The figure which shows the structure of a field apparatus. The figure which shows a maintenance screen. The figure which shows the other example of a maintenance screen.

Explanation of symbols

  2-a master field device serving as a master, 2-b field devices serving as slaves, 4 optical cables, 33 optical communication interface control circuits, 333 waveform distortion detection circuits, 331 waveform distortion correction circuits.

Claims (14)

With multiple field devices that exchange control information for measurement and control,
An upper field device that exchanges communication information with the plurality of field devices;
In a distributed control system provided with a loop-shaped control network having a plurality of field devices and an optical cable transmission path that conveys the communication information so as to circulate and move in one direction through the upper field devices,
The plurality of field devices and the upper field device have an optical communication interface control circuit that transfers the communication information to and from the transmission path,
The optical communication interface control circuit includes a waveform distortion detection circuit for detecting a waveform distortion width included in the received communication information, and the communication information for sending out a correction corresponding to the waveform distortion width detected by the waveform distortion detection circuit. A distributed control system comprising a waveform distortion correction circuit for compensating for the above. The distributed control system according to claim 1,
A distributed control system, wherein a communication encoding system of the communication information exchanged via the optical communication interface control circuit is a Manchester encoding system. The distributed control system according to claim 2,
The distributed control system according to the communication processing method, wherein the communication signal of the Manchester encoding method does not maintain the same level for one bit or more. The distributed control system according to claim 1,
The optical communication interface control circuit converts an optical receiver that converts an optical signal of the communication information coming from the transmission path on the front side into an electrical signal, and converts the information sent to the transmission path on the rear side into an electrical signal. A distributed control system comprising an optical transmitter. The distributed control system according to claim 1,
The plurality of field devices have an identification function for identifying own communication information included in the received communication information, and a prevention function for preventing transmission of communication information identified by the identification function. Distributed control system. In a device controller of a field device or a host field device of a distributed control system provided with a loop-shaped network control loop,
The device controller includes an interface unit between a system control MPU, a system control interface circuit, an MPU work main storage memory, a storage device including a nonvolatile memory for storing communication abnormality information, and an information processing device using an Ethernet controller. And an external bus interface unit implemented as an interface between control devices, a communication control chip, an optical communication interface control circuit, and a maintenance indicator having a display function,
The optical communication interface control circuit includes an optical receiver that converts an optical signal of an optical signal of received communication information, an optical transmitter that converts the communication information to be sent into an optical signal, and distortion included in the received communication information. An apparatus controller comprising: a waveform distortion detection circuit that detects a waveform distortion; and a waveform distortion correction circuit that performs correction on the communication information that sends a correction corresponding to a distortion amount detected by the waveform distortion detection circuit. The device controller of claim 6, wherein
Via the system control interface circuit from the optical communication interface control circuit, to store communication abnormality information in the nonvolatile memory,
The communication abnormality information stored in the nonvolatile memory is read out, and the communication abnormality information is transferred to the information processing device via the system control interface circuit, the Ethernet controller, and the Ethernet driver. Device controller. The device controller of claim 7,
The information processing device has a maintenance screen for displaying the transferred communication abnormality information. The device controller of claim 8,
The apparatus controller, comprising: an output display means for displaying a maintenance screen on which arrangement position information in the apparatus of the field device that has issued the communication abnormality information is displayed. The device controller of claim 9, wherein
An apparatus controller, wherein the maintenance display of the field device displays arrangement position information in the device of the field device that has issued the communication abnormality information. The device controller of claim 6, wherein
An apparatus controller characterized in that measurement of temperatures and the like to be controlled and control of motors and the like are distributed by the plurality of field devices. The device controller of claim 6, wherein
The field device has a waveform distortion detection function for detecting a waveform distortion width by comparing a transmission waveform of the communication information having a normal waveform width to be input with a received waveform after reception, and the communication information for transmission to be sent out The apparatus controller has a waveform distortion correction function for correcting the waveform distortion width to a normal waveform width. The device controller of claim 12,
The plurality of field devices have a communication abnormality detection function that outputs the communication abnormality information when a waveform distortion width by the waveform distortion detection function exceeds a predetermined value, and individual unique address information,
The upper field device device monitors the plurality of field devices based on the communication abnormality information and the unique address information. The device controller of claim 6, wherein
The apparatus controller according to claim 1, wherein the optical communication interface control circuit includes a battery for supplying electricity in place of the power supply when the power supply to the field device is cut off.

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