JP2013130926A - Controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable instrumentation of a controller without complication of a system configuration.SOLUTION: A controller includes a communication interface 150 that is connected to an input/output unit corresponding to a communication protocol superimposing a digital signal upon an analog current signal, and corresponds to the communication protocol.

Description

  One embodiment of the present invention relates to a controller for controlling a device installed in, for example, a plant.

  At the site where production processes are managed, various production processes are managed by installing various devices (for example, sensors, valves, etc.) having a transmission function in the plant and incorporating signals transmitted from the devices into the system. . 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, as a device connected to such a process management system, there is a device equipped with a HART (Highway Addressable Remote Transducer) communication function (hereinafter referred to as “HART communication compatible device”).

  A HART (registered trademark) communication-compatible device has a frequency signal of 1200 Hz and 2200 Hz to a DC signal (analog current) of 4 to 20 mA indicating a measured value or a control value (hereinafter sometimes collectively referred to as “PV value”). A signal generated by superimposing the digital signal converted into is input and output. That is, the HART communication-compatible device can exchange various information in addition to the measurement value and the control value.

  By collecting device and process information through the HART communication in the process management system, it is possible to inform the system user of device failure, maintenance, and the time required for repair. Thereby, the system user can take measures such as preventing a fatal shutdown of the plant in advance. The following Patent Document 1 and Patent Document 2 describe systems using HART communication-compatible devices.

JP 2003-186503 A Japanese Patent No. 4129715

  On the other hand, the PV value, which means the analog current value, is sent to the controller of the process management system and used for process control and monitoring. While the process monitoring system performs centralized monitoring and control, a separate local controller may be provided to perform local control on a device basis. For example, when the control function of a dedicated manufacturer's device is built in, when you want to implement a control cycle at a high speed, or when you want to use a program specialized for a certain control, monitor and set up the equipment and devices installed in the plant. A local controller is used with a process monitoring system, such as when it is desired to do so.

  As the local controller, a controller is typically used. The local controller itself performs monitoring and control. However, by providing a communication interface as an option, it is possible to perform integrated monitoring with a process monitoring system. For example, integrated monitoring can be performed by a process monitoring system via a protocol converter or PLC (programmable logic controller) (see, for example, FIG. 4).

  However, as illustrated in FIG. 4, it is necessary to go through a plurality of devices such as protocol converters for connection, and the system configuration becomes complicated.

  One object of the present invention is to enable instrumentation of a controller without complicating the system configuration.

  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 controller of the present invention is connected to an input / output unit corresponding to a communication protocol for superimposing a digital signal on an analog current signal, and includes a communication interface corresponding to the communication protocol.

  Here, the communication interface transmits information held by the controller to the input / output unit by a digital signal in response to a request by the digital signal from the input / output unit, and the input / output unit transmits the information by the digital signal. The received information may be transmitted to the device monitoring unit via a monitoring system different from the control system of the device connected to the controller.

  The information may include information on the controller and / or information on the device connected to the controller.

  The communication interface may receive the analog current signal from the input / output unit, and the controller may control a device connected to the controller based on the analog current signal.

It is a figure which shows an example of the process management system which concerns on one Embodiment. It is a figure explaining the operation example of the process management system which paid its attention to the controller which concerns on one Embodiment. FIG. 3 is a functional block diagram of the controller illustrated in FIG. 2. It is a figure which shows the structural example of the conventional process management system equipped with the controller.

  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.

  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 more devices 10 that support smart communication. The process management system 1 may include one or a plurality of devices that are not compatible with smart communication.

  An example of “smart communication” is communication conforming to the HART (Highway Addressable Remote Transducer) communication protocol.

  Examples of the devices 10 and 12 include a transmitter and a positioner. 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 HART communication-compatible device 10 includes a controller (hereinafter referred to as a “controller 10A” for distinction from other devices 10), which is an example of a local controller (for an upper controller 17 described later). You can.

  The controller 10A is, for example, a device that requires fine (high accuracy) control of temperature, humidity, pressure, flow rate, etc., a control cycle (for example, 100 ms or less) shorter than the control cycle by the host controller 17, and the like. Is provided. By way of example, the controller 10A is remotely set (designated) from the controller 17, and thereafter locally controls the devices 14a and 14b connected to the controller 10A as a remote set point (RSP).

  An example of the device 14a connected to the controller 10A is an analog input device (for example, a flow meter) that inputs an analog current signal to the controller 10A, and another example of the device 14b is an analog current signal from the controller 10A. An analog output device (eg, a valve positioner).

  In this case, the controller 10A controls the valve opening by the valve positioner 14b based on the flow rate value measured by the flow meter 14a so that the flow rate in the pipe or the like becomes the specified flow rate value (control target value) ( For example, PID control can be performed. The control target value may be specified from a computer or the like directly connected to the controller 10 </ b> A, or may be set remotely from the driving operation unit 19 through the controller 17.

  The process management system 1 exemplarily includes one or a plurality of input / output (IO) units (hereinafter also referred to as “HART-IO”) 11 compatible with HART communication, and one or a plurality of HART communication non-compatible. An input / 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 device 10 (including the controller 10A, the same applies hereinafter) via the controller 17 and the IO unit 11, respectively. In addition, the driving operation unit 19 can transmit information through the controller 17 and analog transmission between the IO unit 13 and the device 12. Through the communication or transmission, the driving operation unit 19 can acquire the measurement values of the devices 10 and 12, and can give the setting values and control values to the devices 10 and 12 based on the measurement values. In other words, the controller 17 and the driving operation unit 19 form an example of a control system that controls a process through a first communication path (or transmission path) that passes through the IO units 11 and 13.

  On the other hand, the device monitoring unit 15 can communicate with the HART communication compatible device 10 via the HART-IO 11 in cooperation with the link module 15A, for example. By the communication, the device monitoring unit 15 can acquire information (for example, process information, failure information, etc.) indicating the state of the device 10, for example. In other words, the device monitoring unit 15 and the link module 15A form an example of a monitoring system that monitors the state and the like of the HART communication-compatible device 10 through the second communication path that passes through the HART-IO 11.

  More specifically, 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 perform TCP / UDP communication with, for example, the link module 15A and the HART-IO unit 11. 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 X-BUS specialized for the communication functions of the controller 17 and the IO unit 13. X-BUS is an example of a digital communication path that enables digital communication between the controller 17 and the IO unit 13.

  The HART communication-compatible device 10 can be connected to the HART-IO 11. The device 12 can be connected to the IO unit 13. For these connections, an analog transmission line for transmitting an analog DC signal (for example, 4 mA to 20 mA) can be used.

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

  Therefore, the devices 10 and 12 can transmit an analog DC signal having a current value (4 to 20 mA) corresponding to the measured value to the controller 17 via the IO units 11 and 13, and from the controller 17 to the IO unit. It is possible to receive an analog DC signal having a current value (4 to 20 mA) corresponding to a set value, a control value, or the like transmitted via 11 and 13.

  Here, the HART-IO 11 and the HART communication compatible device 10 can transmit each other a signal obtained by superimposing a digital signal on the analog DC signal. In other words, the HART-IO 11 and the HART communication-compatible device 10 can simultaneously 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). Note that various data may include measurement values, control values, and the like of the HART communication-compatible device 10.

  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 HART communication compatible device 10) receives the analog DC signal on which the digital signal is superimposed in this way from the HART communication compatible device 10 (or HART-IO 11), the received signal is converted into the analog DC signal and the digital signal. Separated into signal. Thereby, HART-IO11 (or HART communication corresponding | compatible device 10) can acquire the value and data which each of the isolate | separated signal shows.

  In other words, the analog transmission path between the devices 10 and 12 and the IO units 11 and 13 and the digital communication path 18 between the IO units 11 and 13 and the controller 17 are the first communication path in the control system. (Or a transmission line).

  On the other hand, an analog transmission path between the HART communication-compatible device 10 and the HART-IO 11 and a digital communication path 16 between the HART-IO 11 and the link module 15A and the device monitoring unit 15 are the second communication paths in the monitoring system. An example. In other words, the HART-IO 11 transmits the signal acquired by the HART communication to the upper link module 15 </ b> A and the device monitoring unit 15 on a line different from the line for transmitting the analog current signal to the controller 17.

  With the process management system 1 configured as described above, the following effects or advantages can be obtained.

・ Because the equipment monitoring (management) system, which is an accessory function, is separate from the control system line, it does not affect existing systems. Therefore, it is possible to smoothly shift to device management without impairing control reliability. For example, it is not necessary to replace all the controllers 17 and the like from a communication bus line such as the X-BUS18.

-By simply replacing the existing IO unit 13 with the HART-IO 11, an infrastructure capable of easily realizing device management can be provided.

-Existing wiring and terminals can be used as they are.

-It is sufficient to wire communication lines such as Ethernet for equipment management (monitoring system).

-If the reliability of the monitoring system is ensured in the future, simply replace the peripheral device, and use the monitoring system to transmit signals representing variables according to the devices 10 and 12 to the control system for control. It can be used for process control by the system.

  In the system configuration described above, the HART communication-compatible controller 10A connected to the HART-IO 11 is positioned in the same row as other HART communication-compatible devices 10 (for example, a valve positioner and a flow meter) connected to the HART-IO 11. be able to. That is, the controller 10A includes a HART communication interface 150 (see FIG. 3), and can perform HART communication with the HART-IO 11 in the same manner as other devices 10 that support HART communication.

  For example, the controller 10A recognizes an analog output value received from the HART-IO 11 as an RSP that is a remote setting from the HART-IO 11, and an analog output device (for example, a valve positioner 14b) connected to the controller 10A. (For example, PID control) is performed based on information from an analog input device (for example, the flow meter 14a).

  Further, the controller 10A transmits the internal information (eg, MV: control output value, control parameter) of the controller 10A together with the information of the devices 14a and / or 14b connected to the controller 10A to the HART-IO 11 and the TCP / It can be provided to the device monitoring unit 15 (or the link module 15A) via the UDP communication path 16.

  Hereinafter, the operation of the process management system 1 focusing on the controller 10A will be described with reference to FIG.

  First, the RSP of the controller 10A designated by the host controller 17 is output as an analog value (4 to 20 mA) by the analog output of the HART-IO 11 (processing P1). By receiving the analog value, the controller 10A recognizes that the controller 10A is designated as the RSP, and the valve positioner 14b should be locally controlled using the designated analog value as the control target value.

  For example, the controller 10A designated by the RSP locally controls the opening of the valve positioner 14b based on the analog input (process P2) from the flow meter 14a instead of the (upper) controller 17 (process). P3). When the valve positioner 14b has a function of feeding back the opening information to the controller 10A, the controller 10A can acquire the feedback information (opening information) as an analog value (processing P4). .

  The controller 10A is a HART non-compatible device connected to the controller 10A, and if there is information preset in the controller 10A, the controller 10A holds it as information equivalent to a HART compatible device. Further, internal information (control output value, control parameter, etc.) of the controller 10A is held as information equivalent to a HART compatible device.

  When the controller 10A receives a request for information acquisition from the HART-IO 11 that is the master of HART communication as a digital signal of HART communication (process P5), part or all of the information is used as a slave of HART communication. It transmits to IO11 by the digital signal of HART communication (process P6). The information acquisition request transmission instruction (command) to the HART-IO 11 can be exemplarily transmitted from the device monitoring unit 15 (or the link module 15A).

The HART-IO 11 transmits the information received from the controller 10A by HART communication to the device monitoring unit 15 (or link module 15A) via the TCP / UDP communication path 16 (process P7). As a result, the system user can check information on devices connected to the controller 10A in the device monitoring unit 15, internal information of the controller 10A, and the like.
Note that the device monitoring unit 15 can also change data and settings of the controller 10 </ b> A through the controller 17.

  FIG. 3 illustrates a functional block diagram of the controller 10A described above. The controller 10A shown in FIG. 3 includes, for example, an RSP processing unit 110, a PV processing unit 120, a control unit 130, an analog output processing unit 140, and a HART communication interface 150.

  The RSP processing unit 110 processes the above-described RSP designation (analog value of 4 to 20 mA). The processing result is given to the control unit 130, and is used as a control target value of the valve positioner 14b, for example.

  The PV processing unit 120 illustratively receives and processes the measurement value (PV value) of the flow meter 14a described above. The processing result is given to the control unit 130 and used for opening degree control (for example, PID control) of the valve positioner 14b through the analog output processing unit 140.

  The analog output processing unit 140 outputs the control value (PID control value) for the valve positioner 14b provided from the control unit 130 to the valve positioner 14b as a corresponding analog current value of 4 to 20 mA.

  The HART communication interface 150 is a communication interface for performing HART communication with the HART-IO 11, and digital values 0 and 1 are added to an analog DC signal of 4 to 20 mA with two types of frequency signals (for example, 1200 Hz and 2200 Hz). The function of superimposing a digital signal converted (for example, phase modulation) as shown and the analog DC signal on which the digital signal is superimposed are received from the HART-IO 11, and the received signal is separated into an analog DC signal and a digital signal. It has the function to do.

  When the control unit 130 recognizes the designation of the RSP through the RSP processing unit 110, the control unit 130 performs the above-described local control (for example, PID control) of the valve positioner 14b. The control unit 130 can also control HART communication through the HART communication interface 150. As described above, the control unit 130 receives information acquisition requests (commands) from the controller 10A and responds to the requests (commands). ) Transmission processing can be performed through the HART communication interface 150.

  As described above, according to the controller 10A of the present embodiment, since the HART communication interface 150 is provided, HART communication with the HART-IO 11 is performed in the same manner as other devices 10 connected to the HART-IO 11. Can do.

  Therefore, if the controller 10A is connected to the HART-IO 11, not only can the valve positioner 14b, which is an example of the device, be controlled (eg, PID control), but the controller 10A has no complicated system configuration. Information (for example, information on the controller 10A and / or information on the devices 14a and / or 14b connected to the controller 10A) via a monitoring system different from the control system, the equipment monitoring unit 15 (or link module) 15A).

  DESCRIPTION OF SYMBOLS 1 ... Process management system, 10, 12 ... Device, 10A ... Controller (local controller), 11, 13 ... IO unit, 14a ... Device (flow meter), 14b ... Device (valve positioner), 15 ... Equipment monitoring unit, 15A ... Link module, 16 ... (digital) communication path (TCP / UDP communication path), 17 ... (higher level) controller, 18 ... (digital) communication path (X-BUS), 19 ... driving operation unit, 110 ... RSP processing , 120 ... PV processing unit, 130 ... control unit, 140 ... analog output processing unit, 150 ... HART communication interface

Claims (4)

  A controller connected to an input / output unit corresponding to a communication protocol for superimposing a digital signal on an analog current signal, and comprising a communication interface corresponding to the communication protocol. The communication interface transmits information held by the controller to the input / output unit by a digital signal,
The adjustment according to claim 1, wherein the input / output unit transmits the information received by the digital signal to a device monitoring unit via a monitoring system different from a control system of a device connected to the controller. Total.   The controller according to claim 2, wherein the information includes information on the controller and / or information on the device connected to the controller. The communication interface receives the analog current signal from the input / output unit;
The controller according to claim 1, wherein the controller controls a device connected to the controller based on the analog current signal.

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