JP5122398B2 - Valve controller for petrochemical plant - Google Patents

Description

  The present invention relates to a valve control device for controlling a valve incorporated in a petrochemical plant such as an FCC device or an RFCC device for petroleum refining.

  In a petrochemical plant, there is a risk of an explosion or the like due to an error in the control of the controlled fluid, and once the operation is stopped due to an abnormality in the equipment, it takes time to check the equipment to resume the operation. High reliability is required for the valves and valve control devices used.

  Patent Document 1 discloses a single unit test apparatus in which a test device is connected to a valve control device and the test device is driven by operating the test device in order to verify the control characteristics of the valve when the valve is initially installed. Has been proposed.

According to the above-mentioned prior art, even when a regular maintenance or any abnormality occurs other than during the initial installation of the valve, the control characteristics of the valve are verified by connecting the unit test device to the valve control device. can do.
JP-A-9-292310

  However, there is a problem that it is very complicated to carry a single test device for each valve incorporated in a petrochemical plant and connect it to the valve control device for test drive.

  In addition, although a data storage device for storing test data is incorporated in the unit test device, there is a problem that the test data cannot be analyzed on the spot and cannot be evaluated quickly.

  Normally, a valve control microcomputer is incorporated in the valve control device. When controlling a valve at high speed via a hydraulic servo mechanism in order to control a large valve, the microcomputer controls a plurality of control commands from the main controller, and oil pressure, oil temperature, valve opening, etc. Based on the sensor input, a predetermined control calculation is executed, and as a result, it is detected whether the operating state of each load is appropriate while properly controlling the oil pump, servo valve, etc. A plurality of jobs, such as prompt notification if any, are repeatedly executed at a predetermined control cycle.

  It is conceivable that such a microcomputer incorporates functions similar to those of a unit test apparatus and functions for analyzing and evaluating test data. In such a case, however, the control load of the microcomputer becomes heavy, and jobs are processed within a predetermined control cycle. In order to complete the process, there is a problem that it is necessary to use an expensive high-speed microcomputer.

  The present invention has been made in view of the above-mentioned conventional problems, and without using an expensive microcomputer, a single unit test operation of a valve and evaluation of test data at that time can be performed. An object is to provide a valve control device.

In order to achieve the above-mentioned object, the first characteristic configuration of the valve control device of the petrochemical plant according to the present invention is an opening degree for detecting the opening degree of the valve as described in claim 1 of the claims. Based on the valve opening value input from the sensor and the control command value of the valve input from the main controller of the petrochemical plant, a control unit that controls the hydraulic mechanism to feedback control the opening of the valve; A petrochemical system comprising: a display unit capable of acquiring control information of the valve controlled by the control unit from the control unit and displaying the control state of the valve; and an operation unit for performing a test drive of the valve. a plant valve controller is constituted by operation keys the operation unit is input to the display unit, the operation key is shifted to the test mode is operated, and the fully open state of the valve Control characteristics when driving between a closed state, the step response characteristics with respect to a predetermined opening degree, the frequency corresponding to the test drive that contains the response characteristics, the test driver information set via the operating unit between predetermined opening The display unit is configured to display control information corresponding to the test drive information transmitted from the display unit to the control unit, and the display unit is transmitted from the control unit. The control information at the time of test drive is acquired at predetermined time intervals and displayed as a trend graph, and a removable nonvolatile memory for storing the control information at the time of test drive is provided .

  According to the above configuration, since the function of the valve control device is distributed to the display unit and the control unit, each can be configured at low cost, the total cost can be reduced, and the unit test device can be carried as in the conventional case. This saves time and enables the test results to be obtained quickly.

For valves driven through complex hydraulic mechanisms in petrochemical plants, control characteristics when driving the valve between fully open and fully closed, step response characteristics for a predetermined opening, frequency response between predetermined openings The characteristics are extremely important, and such characteristics are measured on the spot and can be visually evaluated by the operator, so that the inspection can be performed very efficiently. In addition, control information of a valve that is test-driven by the control unit is transmitted to the display unit, and the transmitted control information is read out at predetermined time intervals by the display unit, and its characteristics are displayed on the trend graph. Therefore, the operator can quickly evaluate by visually checking the trend graph displayed on the display unit. Furthermore, control information related to a series of tests can be stored cumulatively in a non-volatile memory, and even if it is necessary to analyze with a dedicated analyzer based on the control information, from the display unit By removing the non-volatile memory, the control information can be ported to the analysis device. Further, if it is a non-volatile memory, it can be carried very easily.

As described in claim 2, the second characteristic configuration includes a valve opening value input from an opening sensor that detects the opening of the valve and a control command value of the valve input from a main controller. A control unit that controls the hydraulic mechanism to feedback-control the opening of the valve, a display unit that can display control information of the valve controlled by the control unit, and a test drive for the valve. A valve control device of a petrochemical plant comprising an operation unit, wherein the valve is driven between a fully open state and a fully closed state, a control characteristic, a step response characteristic with respect to a predetermined opening, and a predetermined opening Corresponding to test drive including frequency response characteristics, test drive information set through the operation unit is transmitted to the control unit, and the display unit corresponds to the test drive information transmitted from the control unit. The control unit is configured to display control information, and the display unit acquires the control information at the time of test driving transmitted from the control unit at a predetermined time interval and displays it as a trend graph, and also displays the control information at the time of test driving. A removable non-volatile memory is provided for storing an abnormality determination value in which predetermined control information is preset during control of the valve mechanism based on the control command value input from the main controller. A signal determination unit that determines that an abnormality has occurred and outputs an abnormality signal when the exceeding state continues for a predetermined time, and the signal determination unit is similarly abnormal during control of the valve mechanism based on the test drive information in the inspection mode. The presence or absence of the occurrence of an abnormality is determined, and when it is determined that an abnormality has occurred, an abnormality signal is output.

Control of the valve mechanism based not only on feedback control of the valve mechanism based on the control command value input from the main controller of the petrochemical plant but also on the basis of the test drive information in the inspection mode by the signal determination unit provided in the controller Similarly, the presence or absence of abnormality is detected and an abnormal signal is output, so that even during test drive, it is possible to prevent the occurrence of a serious situation that damages the valve due to the abnormality of the hydraulic mechanism, Test drive can be performed safely .

In the third feature configuration, as described in claim 3, in addition to the first or second feature configuration described above, a shared memory connected to the control unit and the display unit via a LAN is provided. The display unit includes the operation unit, and the display unit transmits the test drive information set through the operation unit to the control unit through the shared memory, and is acquired through the shared memory. The control information corresponding to the test drive information is displayed.

  The valve control device is functionally separated into a control unit that controls the opening degree of the valve and a display unit that displays a control state of the valve by the control unit, and a shared memory provided in each of the display unit and the control unit is a LAN (for example, , CUnet (real-time distributed processing network)) connection enables data sharing. Test drive information set via the operation unit provided in the display unit is transmitted to the control unit via the shared memory, and the valve opening control function including the test drive is realized by the control unit. Control information acquired by the control unit is transmitted to the display unit via the shared memory, and a control information display function is realized based on the control information. Since the functions of the valve control device are distributed between the display unit and the control unit, each can be configured at low cost, the total cost can be reduced, and the trouble of carrying a unit test device as in the past can be saved. Test results can be obtained quickly.

  As described above, according to the present invention, it is possible to provide a valve control device for a petrochemical plant that can perform a single valve test operation and evaluation of test data at that time without using an expensive microcomputer. I can do it now.

  Below, the valve control apparatus built in the FCC apparatus and RFCC apparatus for petroleum refining which are examples of a petrochemical plant is demonstrated. As shown in FIG. 1, a valve control device 1 is incorporated in a hydraulic unit U arranged in the vicinity of a valve V incorporated in a plant, and is a target opening degree with respect to the valve V inputted from a plant main control device CT. Based on the signal and the opening signal of the valve detected by the opening sensor S, the hydraulic mechanism VD is controlled to adjust the opening of the valve V, and the position signal indicating the opening state of the valve V to the main controller CT Is a control device that outputs.

  As shown in FIG. 2, the hydraulic unit U includes a hydraulic mechanism VD including a hydraulic pump, an accumulator, a servo valve for hydraulic control as an actuator, an explosion-proof casing C in which the control device 1 is accommodated, a casing An air unit AU for press-fitting explosion-proof air into C is provided.

  The control device 1 feedback-controls the opening degree of the valve V by controlling the hydraulic mechanism based on the valve opening degree value inputted from the opening degree sensor S and the control command value of the valve V inputted from the main controller CT. Control units 20 and 30, a storage unit that stores control information from the control units 20 and 30, and a display unit 40 that displays the control state of the valve V on the liquid crystal display panel based on the control information stored in the storage unit. ing.

  A transparent glass is disposed on the door of the casing C, and the screen of the liquid crystal display panel provided in the internal control device 1 is configured to be recognized from the outside. A plurality of explosion-proof switches SW1, SW2, SW3 are attached to the door.

  The switch SW1 is a rotary multi-contact switch or a push button switch, and the display screen of the liquid crystal display panel can be switched by rotating or pressing the switch SW1 while maintaining the explosion-proof state of the casing C. It is possible.

  Further, the switch SW2 is a push button type switch that serves as a control mode switching operation unit according to the present invention. By operating the switch SW2, the control device 1 can operate in the local control mode and the remote control while maintaining the explosion-proof state of the casing C. Switch to mode.

  Further, the switch SW3 is a dial switch with a built-in variable resistor, which is a manual operation unit according to the present invention. By rotating the switch SW3 in the local control mode, the casing C is kept in an explosion-proof state, and the valve V The opening can be manually controlled.

  The control device 1 controls the valve opening value input from the opening sensor S that detects the opening of the valve V, the control command value of the valve V input from the main control device CT or the manual operation unit SW3, that is, the target opening. A control value for a servo valve that drives the valve V is calculated based on the degree signal, and a plurality of control units are provided for feedback control of the opening degree of the valve V based on the calculated control value.

  As shown in FIG. 3, the valve V to be controlled is a slide valve V that adjusts the flow path P to a predetermined opening according to the operation state of the plant, and is driven by pressure oil supplied via a servo valve. The valve body V1 is slid and driven through a valve rod V2 connected to the piston of the hydraulic cylinder SL. A pair of magnetostrictive opening sensors S (S1, S2) are incorporated between the piston and the valve stem V2 via a coupling, and the output of the opening sensor S is input to the control device 1. The valve V to be controlled is not limited to the slide valve V, and the same applies to other valves such as a plug valve and a butterfly valve.

  The magnetostrictive opening sensor S is a position of the magnet, that is, the position of the valve V, by measuring the propagation time of torsional strain generated by the magnet that moves in a non-contact manner on the sensor rod as the piston moves forward and backward. It is a sensor that measures the opening.

  As shown in FIG. 4, the control device 1 includes two control unit substrates 2 and 3, a display unit substrate 4, a terminal substrate 5, and the like, and each is connected by a single or a plurality of connectors. Two control units 20 and 30 according to the present invention are constituted by the two control unit substrates 2 and 3, respectively, and a display unit 40 is constituted by the display unit substrate 4.

  Various signals are inputted to and outputted from the main control device CT and the valve drive mechanism that is a control target in the control unit substrates 2 and 3 and the display unit substrate 4 via the terminal substrate 5.

  Specifically, the control command value of the valve V is input from the main control device CT to the control units 20 and 30 via the terminal board 5, and the position signal of the valve V is transmitted from the control units 20 and 30 to the main control device CT. Is output. Further, the valve opening values from the pair of opening sensors S are input via the terminal board 5, and control signals are output from the control units 20 and 30 to the servo valves.

  Further, the output of the switch SW2 as the control mode switching operation unit and the control command value from the switch SW3 as the manual operation unit are input to the control unit substrates 2 and 3 via the terminal substrate 5, and the output of the switch SW1. Is directly input to the display unit substrate 4.

  As shown in FIG. 6, each of the pair of control units 20 and 30 and the display unit 40 includes a CPU, a ROM that stores a control program executed by the CPU, and a RAM that is used as a working area. A microcomputer and peripheral circuits are mounted, and the control program is executed by the CPU, thereby realizing an intended valve control function and the like.

  Each of the control units 20 and 30 and the display unit 40 is provided with a shared memory CM that functions as a communication bus and is connected via a local network such as CUnet (registered trademark of Step Technica Co., Ltd.). Control information, control parameters, display data, and the like by 30 are shared via the shared memory CM.

  Each shared memory CM is divided into an area where the control information can be read and written by itself and an area where the writing of the control information is prohibited and the control information written by another control unit or the display unit can be read out via the local network. Predetermined cycle, for example, 10 msec. Information written in each shared memory in a cycle is copied to a corresponding area in another shared memory.

  That is, control information written in the writing area of the shared memory CM provided by the CPU of each of the control units 20 and 30 and the display unit 40 is copied to the reading area of each shared memory CM via the local network. Thus, it is configured such that communication of control information and the like can be performed without using the CPU.

  A color liquid crystal display unit 45 is incorporated in the display unit substrate 4, and the control state of the valve as shown in FIG. The monitor screen is displayed.

  The display unit board 4 is equipped with a battery backed-up several Mbytes of SRAM 44 as a first storage element, and control information by the control units 20 and 30 obtained via the shared memory CM is stored in a ring buffer format. It is comprised so that.

  More specifically, the SRAM 44 has a first storage area for storing the control information in a ring buffer format, and when the control information includes alarm information, the SRAM 44 stores the predetermined information immediately before the occurrence of the alarm information stored in the first storage area. A second storage area is provided for storing time control information until it is output to the information collecting apparatus via at least the optical communication interface.

  Furthermore, the memory capacity is larger than that of the SRAM 44, and there are several Gbytes (for example, 2 Gbytes) of SD memories 46 which are detachable nonvolatile memories in which control information stored in the first storage area of the SRAM 44 is cumulatively stored. ing.

  The control information includes a control command value of the valve V input from the main controller CT, a valve opening value input from the opening sensor S, a control value for the servo valve, a thrust pressing pressure for the valve, and a thrust pulling pressure. , Measurement data such as pump pressure, accumulator pressure, oil temperature, oil liquid level, pump motor current, abnormality data detected as a result of self-diagnosis by the control units 20 and 30 based on these measurement data, control described later Abnormal data such as runaway of the sections 20 and 30 and cumulative operating data such as a cumulative working distance or a cumulative working time of a hydraulic cylinder or the like that drives the valve are included.

  In addition, the display unit substrate 4 communicates with a personal computer located at a remote place via a LAN, and transmits a control state displayed on the color liquid crystal display unit 45 to the personal computer. 42, an infrared interface 43 capable of communicating with a personal computer as an information collecting device in a state where the door of the explosion-proof casing C is closed without opening the door.

  When the display unit 40 writes various control parameters for initial setting input from the information collecting device via the infrared interface 43 to its own shared memory CM, the display unit 40 is distributed via the local network, and each control unit 20, The control parameter is copied to 30 shared memories CM.

  In the control parameter, a control right parameter that sets which of the two control units 20 and 30 has an initial control right, and a sensor selection that sets which of the doubled opening sensors S is initially selected Parameter, signal level with respect to the control command value of the valve V input from the main controller CT to the control units 20 and 30 (for example, current specifications that define the opening degree 0% to opening degree 100% from 4 mA to 20 mA, Voltage specification specified from 0V to 10V), signal level of the opening signal input from the opening sensor S, signal level and upper / lower limit values of thrust pressure of the hydraulic cylinder, output signal level to the servo valve, main controller CT The predetermined control parameters required for operating the system, such as the signal level of the position signal output to the control unit, the abnormality determination reference value of the opening sensor C detected by the control units 20 and 30, and the like. Data are included.

  As shown in FIG. 6, a control command value from the main control unit CT is input to the microcomputers 21 and 31 via the input signal processing units 26 and 36 in each of the control units 20 and 30, and the opening signal The output signals of the pair of opening sensors S1 and S2 are input to the microcomputers 21 and 31 via the processing units 22 and 32, respectively.

  The input signal processing units 26 and 36 and the opening degree signal processing units 22 and 32 include an isolation amplifier that electrically separates signals and an A / D converter that converts an analog output signal of the isolation amplifier into a digital signal. ing.

  In addition, the control values for the servo valves SV output from the microcomputers 21 and 31 are output to the control valves 20 and 30 to the servo valves SV via the servo output sections 23 and 33, respectively. The output position of the valve V to the main controller CT that has been output is configured to be output via the position signal output units 24 and 34.

  The servo output units 23 and 33 include a D / A converter that converts digital control value information into an analog signal, and a driver circuit that amplifies the output. The position signal output units 24 and 34 include an isolation circuit that electrically separates digital opening position information, and a D / A converter that converts the output of the isolation circuit into an analog signal.

  Each of the control units 20 and 30 includes a remote control mode for driving and controlling the valve V based on a control command value input from the remotely installed main control device CT by operating a switch SW2 as a control mode switching operation unit, The control mode can be switched to any one of the local control modes for driving and controlling the valve V based on a control command value input from a manual operation unit (switch SW3) installed in the vicinity.

  The control unit (in this case, the control unit 20) to which the control right is set based on the control parameters described above is the valve opening degree input from the opening degree sensors S1 and S2 in any control mode. Based on the valve opening value and the control command value of the opening sensor selected by the sensor selection parameter among the values, a digital PID calculation is performed to calculate a control value for the valve V, and an electromagnetic type is calculated based on the calculated control value. A control signal is output to the servo valve SV.

  Similarly, the standby control unit (in this case, the control unit 30) that does not have the control right also includes a sensor selection parameter of any one of the valve opening values input from the opening sensors S1 and S2. Based on the valve opening value of the opening sensor selected in step 1 and the control command value input from the main controller CT or the switch SW3, a digital PID calculation is performed to calculate a control value for the valve V, and the calculated control value Based on the control signal, a control signal is output to the servo valve SV.

  Then, each control part 20 and 30 selects the valve opening value from any one opening sensor based on the predetermined priority setting conditions set to each opening sensor S1, S2, Calculate the control value.

  Predetermined priority setting conditions include, in addition to the sensor selection parameters described above, whether or not a feedback loss occurs in which the valve opening value does not converge to a predetermined range corresponding to a control signal based on the control command value for a predetermined time. The occurrence of a reverse DEV value in which the state in which the deviation between the control command value and the valve opening value changes in the increasing direction continues for a predetermined time period. The feedback loss is an abnormality due to deterioration of the opening sensor, and the reverse DEV value is an abnormality due to incorrect wiring. These are detected by a signal determination unit 260 (see FIG. 7) described later.

  When each of the control units 20 and 30 determines that a feedback loss or a reverse DEV value has occurred in the opening sensor S selected by the sensor selection parameter, it switches to the other opening sensor S and opens the currently selected opening sensor S. The degree sensor information, the abnormality information of the opening sensor in which an abnormality has occurred, and the like are stored in its own shared memory CM.

  Information stored in each shared memory CM is written to the shared memory of the display unit 40 via the local network, and the display unit 40 monitors the color liquid crystal display unit 45 based on the contents of its own shared memory CM. The information is displayed and stored in the SRAM 44 and the SD memory 46.

  Further, for each opening sensor S, when the deviation of the DEV value, which is the deviation between the control command value and the valve opening value, exceeds the abnormality determination threshold, the opening sensor S is provided in the control device 1 without switching. Activate the alarm to sound.

  Note that various abnormality determination thresholds (signal level threshold, duration, etc.) for the opening sensor S and the like are set in advance by the personal computer 70 for maintenance and stored in each shared memory CM.

  When the control mode switching operation unit SW2 is switched, the control units 20 and 30 have a deviation between the control command value input from the manual operation unit SW3 and the control command value input from the main controller CT. Are provided with control mode switching control units 21a and 31a for determining whether or not to switch the control mode.

  When the control mode switching operation unit SW2 is operated in the remote control mode in which the valve V is controlled based on the control command value input from the main controller CT, the control mode switching control units 21a and 31a are manually operated. When the deviation between the control command value input from the unit SW3 and the control command value input from the main controller CT is within a predetermined range, preferably approximately equal, the control mode by the control units 20 and 30 is controlled locally. Switch to mode.

  When the control mode switching operation unit SW2 is operated in the local control mode in which the valve V is controlled based on the control command value input from the manual operation unit SW3, the control mode switching control units 21a and 31a are When the deviation between the control command value input from the main controller CT and the control command value input from the manual operation unit SW3 is within a predetermined range, preferably approximately equal, the control mode by the control units 20 and 30 is changed. Switch to remote control mode.

  Further, on the display unit 40, the manual operation unit SW3 is operated so that the deviation between the control command value input from the manual operation unit SW3 and the control command value input from the main controller CT converges within a predetermined range. The guidance display part 41a which guides so that it may do is provided.

  The guidance display unit 41a has a predetermined range of deviation between the control command value input from the manual operation unit SW3 and the control command value input from the main controller CT when the control mode switching operation unit SW2 is switched. When it is larger, a message prompting the manual operation is displayed on the display screen of the color liquid crystal display unit 45 so as to change the control command value input from the manual operation unit SW3 so that the deviation converges to a predetermined range. .

  When the control command value input from the manual operation unit SW3 is changed by a manual operation, the control mode switching control units 21a and 31a become substantially the same value as the control command value input from the main controller CT at that time. Alternatively, the control mode is switched when the control command value input from the main controller CT becomes substantially equal to the control command value input from the manual operation unit SW3.

  If the control mode is switched when the deviation between the control command value input from the manual operation unit SW3 and the control command value input from the main controller CT is large, there is a possibility that an appropriate plant operating state cannot be secured. Therefore, the control mode is switched on condition that the deviation converges to a predetermined range.

  For example, the operator operates the manual operation unit SW3 to set the control command value to a value close to the control command value input from the main controller CT, thereby maintaining an appropriate plant operating state. The control mode can be switched. Note that the predetermined range, which is the deviation convergence condition, is a value that is appropriately set depending on the target plant, and is not particularly limited.

  As shown in FIG. 7, the control unit 20 includes a relay circuit for switching whether or not to connect a control signal output to the servo valve to the servo valve SV, and a position signal signal output to the main control unit CT. Is provided with a switch circuit 250 (250a, 250b) that is a relay circuit for switching whether or not to connect the signal line to the signal line to the main control unit CT. The switch circuit 250 (250a, 250b) is turned off when it does not have the control right. The control unit 30 is similarly configured.

  Therefore, the drive current for the servo valve SV is output only from the control unit (20 or 30) having the control right, and the position signal of the valve V is output to the main control unit CT, so that no signal interference occurs. It is configured as follows.

  When an abnormality occurs in the control unit (20 or 30) having the control right, a control right transfer signal is output to the standby control unit (30 or 20), and the standby control unit (30 or 20) When the delivery signal is detected, the switch circuit 250 is turned on to continue the control of the valve.

  Hereinafter, the transfer of the control right will be described in detail by taking the control unit 20 in the remote control mode as an example, but the same applies to the local control mode, and the control unit 30 is also the same. The control unit 20 includes a plurality of abnormality detection units that detect its own abnormality. If the abnormality detection unit detects an abnormality of itself when it has the control right, the switch circuit 250 is turned off so as to cut off its control signal, and the control right is transferred to the other control unit 30 It is configured to output a signal. Further, at that time, the alarm unit provided in the control device 1 is activated to sound.

  As shown in FIG. 7, a hardware watchdog circuit 220 and software watchdog timer 210 are provided as an abnormality detection unit.

  The watchdog circuit 220 is reset by a watchdog pulse (hereinafter referred to as “WD pulse”) input at a predetermined cycle from the microcomputer 21 and outputs an abnormal signal when the counter circuit exceeds a predetermined value. If a malfunction such as runaway occurs in the CPU of the microcomputer 21 for some reason and the state where no WD pulse is input continues for a predetermined time, the counter circuit becomes larger than the predetermined value and an abnormal signal is output. The

  The watchdog timer 210 includes firmware having a counter that is automatically counted by an internal timer of the microcomputer 21 and a program that resets the value of the counter by software, and resetting by a program is performed for a predetermined time due to a runaway of the CPU or the like. If not, an abnormal signal (a signal described as “overflow” in the figure) is output by the firmware.

  When an abnormal signal is input from either the watchdog circuit 220 or the watchdog timer 210, a watchdog error circuit 230 having a latch circuit that retains the state is provided. A control right delivery signal (in the figure, a signal described as “control CPU abnormality / normal”, which is a high level when normal and a low level when abnormality) is output.

  In FIG. 7, a signal described as “other control CPU abnormality / normal” is input to the microcomputer 21, and this signal is a signal from a watchdog error circuit provided in the other control unit 30.

  The switch circuit 250 described above is controlled by an output switching circuit 240 having an AND gate. That is, the switch circuit 250 is turned on when the high-level control switching signal output from the microcomputer 21 having the control right and the high-level control right delivery signal output from the watchdog error circuit 230 are input. When the control signal and the position signal are output and at least one of the control switching signal and the control right delivery signal is at a low level, the switch circuit 250 is turned off. Accordingly, the switch circuit 250 is turned off by the low-level control switching signal output from the waiting microcomputer 21 having no control right.

  Therefore, regardless of the output state of the own control signal, the abnormal signal output from either the watchdog circuit 220 or the watchdog timer 210 blocks the own control signal and the position signal, and the abnormal signal is controlled. It is output to another control unit 30 as a delivery signal.

  Further, as the abnormality detection unit, a signal determination unit 260 that is a functional block for detecting any abnormality of the opening sensor S, the servo valve SV, and the control command value based on a control program executed by the CPU is provided. .

  The signal discriminating unit 260 includes an opening value of the valve V input from the opening sensor S, a control command value input from the main controller CT, a current value for the servo valve SV output based on the result of the PID calculation, For each of the position signals of the valve V output to the main controller CT, it is determined that there is an abnormality when a state exceeding any of the upper and lower limit abnormality determination thresholds stored in the shared memory CM continues for a predetermined time. The result is stored in the shared memory CM. The current value is configured such that the output value from the servo output unit 23 is monitored by the current detection unit shown in FIG.

  When any of the above-described abnormalities is detected by the signal discriminating unit 260, the CPU abnormal signal output at a high level from the microcomputer 21 at the normal time is switched to the low level, and the low-level CPU abnormal signal is changed to the watchdog error circuit 230. The control right delivery signal latched at the low level by the watchdog error circuit 230 is output to the waiting control unit 30. Note that when the CPU abnormality signal is switched to the low level, the operation of the watchdog circuit 220 is stopped.

  That is, when any abnormality is detected by the signal discriminating unit 260, the abnormality signal is output to block the own control signal and the position signal regardless of the output state of the own control signal and the position signal. Is output to another control unit as a control right delivery signal.

  In addition, an excessive difference between the control units 20 and 30 in the valve opening value and the control value based on each valve opening value based on the control information such as the valve opening value and the control value stored in the shared memory CM. When it is determined that there is a possibility that an error has occurred in one of the redundantly designed systems, control is continued, that is, an alarm is issued from the alarm unit without handing over the control right. Output to notify that there is a need for maintenance.

  When the above-described watchdog circuit 220, watchdog timer 210, watchdog error circuit 230 and their input / output signal ports assigned to the microcomputer 21 receive abnormal signals from the control units 20 and 30 having the control right. Control right acquisition circuits 25 and 35 for outputting a control right transfer signal to the other control units 30 and 20 are configured.

  When a low-level control right delivery signal (“other control CPU abnormality / normal” signal in FIG. 7) is input from the control right acquisition circuit 35 of the control unit 30 having the control right to the standby control unit 20, The control right is handed over to the control unit 20. The control unit 20 switches the control switching signal for the output switching circuit 240 from the low level to the high level, turns on the switch circuit 250, and continues the control on the valve V.

  As described above, not only the control unit having the control right but also the backup control unit not having the control right is input from the valve opening value input from the opening degree sensor and the main controller or the switch SW3. The control value of the actuator that drives the valve is calculated based on the control command value, and the control signal is output to the actuator based on the calculated control value. Therefore, even when the control right is switched, there is no response delay immediately. It becomes possible to continue control appropriately.

  Even when the abnormality is detected by the signal determination unit 260 of the control unit 20 having the control right and it is necessary to hand over the control right to the standby control unit 30, the signal determination unit 260 of the standby control unit 30 is required. If it is recognized based on the control information stored in the shared memory CM that the same abnormality is detected by the control signal, the servo current is determined so that the valve V is closed without determining the control right and handing over the control right. Perform a fail-safe operation that sets the value to zero.

  In addition, even when an abnormality is detected by the signal determination unit 260 of the control unit 20 having the control right and it is necessary to transfer the control right to the standby control unit 30, it is input from the standby control unit 30. If the control right delivery signal is at a low level, that is, it can be determined that some abnormality has occurred, it is determined that the control is impossible, and the servo current value is set so that the valve V is closed without handing over the control right. Perform a fail-safe operation that sets to zero.

  Further, the signal determination unit 260 not only detects the abnormality for the above-mentioned control right delivery, but also the pressure of the pump constituting the hydraulic mechanism VD, the pressure of the accumulator, the ESD hydraulic pressure, the hydraulic fluid level, the thrust push of the hydraulic cylinder SL. Whether or not an abnormality has occurred in the pressure or the pulling pressure (detected by the pressure sensor) is determined based on the abnormality determination threshold or the determination time included in the control parameter stored in advance in the shared memory CM. The alarm unit is configured to operate when it is determined.

  Various information such as which control unit has acquired the control right, which opening sensor is selected for control, valve control state, various abnormal states described above, etc. It is displayed on the color liquid crystal display unit 45 provided in the display unit 40 via the shared memory CM, or displayed on the screen of the personal computer PC connected via the communication interface 42.

  Each of the control units 20 and 30 reads a control command value, an opening value from the opening sensor S, a PID control calculation process, and controls a servo valve at a preset control cycle (for example, 10 msec. Cycle). A series of processing such as output processing of signals and position signals, abnormality detection processing, and the like are repeatedly executed, and the result is stored in its own shared memory CM.

  By the local network connecting the shared memories CM, mutual data is read and written in substantially the same cycle as the above-described control cycle, and the data is shared with each other.

  The display unit 40 performs display processing based on the control information stored in the shared memory CM, and further displays preset control information in the SRAM 44 together with time information in a cycle longer than the above-described control cycle (for example, 1 second cycle). In addition to writing, the data is written to the SD memory 46. The SRAM 44 stores control information for about 4 hours in a ring buffer system, and the SD memory 46 stores control information for several years.

  Note that control data at the time of test drive in the inspection mode to be described later is written in the SD memory 46 at substantially the same cycle as the read / write cycle of the shared memory CM via the local network or an allowable cycle required for evaluation. It is.

  The color liquid crystal display unit 45 is constituted by a touch panel type, and the menu keys are scrolled and displayed by operating the scroll keys shown in the upper right part of FIG. An inspection mode key is prepared as one of the menu keys, and the control device is configured to shift to the inspection mode by pressing the inspection mode key. The inspection mode is selected when the valve is initially installed, at regular maintenance, when some abnormality occurs, and the like, and does not interfere with the operation of the plant by the main controller CT.

  When the inspection mode is entered, an operation key that is an operation unit for performing a test drive of the valve is displayed on the color liquid crystal display unit 45. Operation that allows selection of a plurality of inspection items such as control characteristics when the valve is driven between a fully open state and a fully closed state, a step response characteristic with respect to a predetermined opening degree, and a frequency response characteristic between the predetermined opening degrees by the display unit 40 A key is displayed, and when any key is selected, the screen is switched to an operation screen corresponding to the inspection item.

  For example, when inspecting the control characteristics when the valve is driven at full speed between the fully open state and the fully closed state, a screen as shown in FIG. 8A is displayed. When the display unit such as system pressure or charge pressure is pressed, a numerical input key pops up on the screen, the required value is set via the numerical input key, and when the start key is operated, the test drive is activated. Be started.

  The display unit 40 will be described with respect to the control unit 20 (here, the case where it is test-driven by the control unit 20 having the control right via the shared memory CM. However, if the control unit 30 has the control right, the control unit 20 The control information indicating that the inspection mode is in effect and 4 mA data indicating an opening degree of 0% are transmitted as a control command value in place of the control command value from the main controller CT.

  The control unit 20 controls the valve opening to 0% based on the value of the opening sensor, and transmits a position signal indicating that the valve opening is 0% to the display unit 40 via the shared memory CM.

  When the display unit 40 that has confirmed this state transmits 20 mA data indicating an opening degree of 100% as a control command value to the control unit 20 via the shared memory CM, the control unit 20 displays the set system pressure, charge pressure, and the like. Based on the parameters, the valve is driven and controlled to 100% opening at full speed.

  After transmitting the 20 mA data, the display unit 40 starts timer counting and starts drawing a trend graph in the graph drawing area partitioned on the screen. That is, a trend graph is drawn by reading a valve position signal input from the control unit 20 via the shared memory CM at a predetermined interval and plotting the value at a position corresponding to the timer count value. The interval for reading the position signal from the shared memory CM is not particularly limited, and may be any interval that can be appropriately evaluated, and is a value that is appropriately set depending on the inspection item.

  In the trend graph shown in FIG. 8A, the alternate long and short dash line indicates a control command and the solid line indicates a position signal.

  When the valve position signal transmitted from the control unit 20 reaches 100% of the opening degree, the timer value at that time is displayed and the timer count is stopped. When a predetermined time (about 1 second) elapses, measurement (from the shared memory CM) is performed. Reading).

  Next, when the start key is operated, the display unit 40 transmits 4 mA data indicating an opening degree of 0% as a control command value to the control unit 20 via the shared memory CM, and repeats the same processing.

  The operator displays the trend graph displayed on the display screen, the time when the valve is controlled at full speed from fully closed to fully open, and the time when the valve is controlled at full speed from fully open to fully closed. Read and evaluate as.

  Note that the control units 20 and 30 not only detect abnormalities for control right delivery, but also the pressure of the pump constituting the hydraulic mechanism VD, the pressure of the accumulator, the ESD hydraulic pressure, and the oil liquid level when the valve is tested. The abnormality determination threshold value and the determination time included in the control parameter stored in advance in the shared memory CM indicate whether or not an abnormality has occurred in the thrust pushing pressure or the pulling pressure (detected by the pressure sensor) of the hydraulic cylinder SL. The alarm unit is configured to operate when it is determined that the abnormality is detected.

  The display unit 40 also reads control information other than the valve position signal input via the shared memory CM at a predetermined interval, and stores the timer value and control information in a state where the test item at that time can be identified. Write to memory 46.

  When a detailed analysis is required, it is possible to remove the SD memory and port the data to an external evaluation device.

  That is, the display unit 40 transmits the test drive information set through the operation unit to the control unit 20 through the shared memory CM, and displays control information corresponding to the test drive information acquired through the shared memory CM. Is configured to do.

  For example, when inspecting the step response characteristic for a predetermined opening, a screen as shown in FIG. 8B is displayed. The step response characteristics when the valve opening degree is changed by ± 5% for each of 25%, 50% and 75% are inspected.

  First, when the lamp of 25% (the left square mark of the “25%” in the figure) lights up and the start key is operated, the display unit 40 controls the control unit 20 via the shared memory CM. 8 mA data indicating an opening degree of 25% is transmitted as a value, and thereafter, +0.8 mA and -0.8 mA are alternately changed in a predetermined cycle. The controller 20 controls the valve opening stepwise based on parameters such as the set system pressure and accumulator pressure.

  The display unit 40 draws the same trend graph as described above based on the valve position signal transmitted from the control unit 20 via the shared memory CM at this time.

  When the step drive of the setting cycle is completed, the 50% lamp (the left square mark in the place of “50%” in the figure) is turned on, and when the start key is operated, the display unit 40 is connected via the shared memory CM. Then, 12 mA data indicating an opening degree of 50% is transmitted to the control unit 20 as a control command value, and thereafter, +0.8 mA and -0.8 mA are alternately changed in a predetermined cycle. The display unit 40 draws the same trend graph as described above based on the valve position signal transmitted from the control unit 20 via the shared memory CM at this time.

  Further, similarly, when the step driving of the setting cycle is completed, the 75% lamp (the left square mark in the notation of “75%” in the figure) is turned on, and when the start key is operated, the display unit 40 is 16 mA data indicating an opening degree of 75% is transmitted as a control command value to the control unit 20 via the shared memory CM, and thereafter, +0.8 mA and -0.8 mA are alternately changed in a predetermined cycle. The display unit 40 draws the same trend graph as described above based on the valve position signal transmitted from the control unit 20 via the shared memory CM at this time.

  In this way, the operator can evaluate by visually confirming the trend graph of the step response characteristics displayed on the screen.

  For example, when inspecting the frequency response characteristics between predetermined openings, enter each opening in the two opening input fields displayed on the screen, enter the switching frequency in the frequency input field, and press the start key. When operated, the display unit 40 transmits a control command value to the control unit 20 so that the opening degree is switched at the set frequency.

  The display unit 40 draws a trend graph on the screen based on the valve position signal controlled by the control unit 20 via the shared memory CM.

  FIG. 8C is an inspection screen for linearity / hysteresis characteristics. In the figure, when the lower arrow “valve open” and upper arrow “valve open” are set with the numeric input keys, the control command value changes step by step at the set valve opening. A position signal is recorded. In other words, it is calculated whether there is hysteresis in the control characteristics when the valve is changed from fully closed to fully open and when the valve is changed from fully open to fully closed, and whether linearity is ensured. Can be evaluated.

  In the figure, the upper row is an operation section for setting whether or not to record the inspection item at this time in the memory. After the up and down operation is displayed with the scroll key to display a desired item and the item is pressed and selected. Each data is recorded by operating the “record” key.

  As described above, the functions of the control units 20 and 30 that execute the control sequence for the valve V and the display unit 40 that displays the result are distributed via the shared memory CM. Display processing can be smoothly performed without causing a delay in control due to a load for display processing.

  The display unit 40 writes the above-described measurement data and abnormal data from the control units 20 and 30 to the first storage area of the SRAM 44 via the shared memory CM. When abnormal data occurs, the display unit 40 several minutes before the time of occurrence. Are read from the first storage area and written as freeze data in the second storage area.

  Furthermore, when abnormal data occurs, the display unit 40 displays abnormality occurrence information specifying the abnormality type on the color liquid crystal display unit 45 and sounds an alarm as necessary.

  When a maintenance personal computer 70 is connected via the infrared interface 43 when periodic inspection or some abnormality occurs, the display unit 40 is stored in the SRAM 44 in response to a request from the personal computer PC. The measured data and abnormality data read out are output to the personal computer PC.

  It should be noted that the optical communication using other wavelengths is not limited to the infrared interface 43 as long as it is an interface capable of communicating with the personal computer PC with the door closed without opening the casing C of the explosion-proof structure. It may be an interface. For example, an optical fiber may be interposed between the optical communication interface provided in the display unit and the coupler fixed to the door of the casing C so as to be connected to the personal computer PC via the optical fiber.

  The various embodiments described above are examples of the present invention, and specific circuit configurations and the like of each part can be appropriately changed and designed within the scope of the effects of the present invention.

Block diagram of a system incorporating a control device according to the present invention Illustration of hydraulic unit Illustration of valve, hydraulic cylinder, opening sensor Explanatory drawing of the board which constitutes the control device built in the hydraulic unit Illustration of the screen displayed on the color liquid crystal display unit by the display unit Functional block configuration diagram of two control units and display unit constituting the control device Configuration diagram of the main part of the control unit Screen illustration of inspection mode

1: control device 20, 30: control unit 21a, 31a: control mode switching control unit 40: display unit 41a: guidance display unit 43: optical communication interface (infrared interface)
CT: main controller S, S1, S1: opening sensor SV: actuator (servo valve)
SW2: Control mode switching operation unit SW3: Manual operation unit V: Valve VD: Hydraulic mechanism

Claims (3)

Based on the valve opening value input from the opening sensor that detects the valve opening and the control command value of the valve input from the main controller of the petrochemical plant , the hydraulic mechanism is controlled to open the valve. A control unit that feedback-controls the degree, a display unit that can obtain control information of the valve controlled by the control unit from the control unit and display a control state of the valve, and a test drive for the valve A valve control device of a petrochemical plant comprising an operation unit,
The operation part is composed of operation keys that are input to the display part, and when the operation key is operated, the operation mode is shifted to the inspection mode, and the control characteristics when the valve is driven between the fully open state and the fully closed state, Corresponding to test drive including step response characteristics for a predetermined opening and frequency response characteristics between predetermined openings , test drive information set via the operation unit is transmitted from the display unit to the control unit, The display unit is configured to display control information corresponding to the test drive information transmitted from the control unit,
The display unit includes a removable nonvolatile memory for acquiring control information at the time of test driving transmitted from the control unit at a predetermined time interval and displaying the information as a trend graph and storing the control information at the time of test driving. and that the valve control device for a petrochemical plant. Based on the valve opening value input from the opening sensor that detects the valve opening and the control command value of the valve input from the main controller, the hydraulic mechanism is controlled to feedback control the valve opening. A valve control device for a petrochemical plant, comprising: a control unit for performing control, a display unit capable of displaying control information of the valve controlled by the control unit, and an operation unit for performing a test drive of the valve. ,
Corresponding to the test drive that includes the control characteristics when driving the valve between the fully open state and the fully closed state, the step response characteristic with respect to the predetermined opening, and the frequency response characteristic between the predetermined opening, via the operation unit The set test drive information is transmitted to the control unit, and the display unit is configured to display control information corresponding to the test drive information transmitted from the control unit,
The display unit includes a removable nonvolatile memory for acquiring control information at the time of test driving transmitted from the control unit at a predetermined time interval and displaying the information as a trend graph and storing the control information at the time of test driving. ,
When a state in which predetermined control information exceeds a preset abnormality determination value continues for a predetermined time during the control of the valve mechanism based on the control command value input from the main control device to the control unit, an abnormality occurs. A signal determination unit for determining and outputting an abnormal signal, and the signal determination unit similarly determines whether or not an abnormality has occurred during the control of the valve mechanism based on the test drive information in the inspection mode, Valve controller for petrochemical plant that outputs an abnormal signal when judged . Each of the control unit and the display unit is provided with a shared memory connected to the LAN, and the display unit includes the operation unit, and the display unit displays test drive information set via the operation unit. The valve control device of a petrochemical plant according to claim 1 or 2 , wherein control information corresponding to the test drive information transmitted to the control unit via the shared memory and acquired via the shared memory is displayed. .

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