JP5199746B2 - 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.

  The valve control device is normally remotely controlled based on a control command from a remotely installed main control device. However, when a problem occurs in the main control device during maintenance such as inspection. May require local control independent of control commands from the main controller.

As such a valve control device, Patent Document 1 discloses a local control by a control device that integrates a drive device that drives a valve and a control device that controls the opening of a valve based on a detection signal such as a flow rate of fluid. A valve control device having a control mode switching unit that switches between a mode and a remote control mode by a central control device has been proposed.
Japanese Unexamined Patent Publication No. 63-135679

  In the valve control device described in Patent Document 1, the valve opening is controlled to be a control command value during remote control, and the valve opening is set by the setting unit during local control when the mode switching unit is switched to the manual side. And the valve opening degree is controlled based on the flow rate value thereafter.

  However, when switching from the remote control mode to the local control mode, for example, if a value that is significantly different from the control command value at that time is set via the setting unit, abnormal fluctuations are given to the plant. There was a concern that it could lead to a serious accident.

  The present invention has been made in view of the above-described conventional problems, and when the control mode switching operation unit is switched to either the remote control mode or the local control mode, an appropriate operation state of the plant is obtained. An object of the present invention is to provide a valve control device for a petrochemical plant that can be maintained.

In order to achieve the above-mentioned object, the first characteristic configuration of the valve control apparatus of the petrochemical plant according to the present invention is the valve opening input from the opening sensor as described in claim 1 of the claims. A control unit that drives and controls the valve based on the control value for the degree value and the valve, a remote control mode that controls the driving of the valve based on a control command value input from the main controller, and an input from the manual operation unit A petrochemical plant valve control device comprising a control mode switching operation unit capable of switching the control unit to any one of the local control modes for driving and controlling the valve based on a control command value. , whether the control command value input from the previous SL manual operating unit, based on a deviation between a control command value input from the main control unit, switches the control mode Provided before Symbol controller the control mode switching control section for determining, when the control mode switching control section of the control mode switching operation unit is switched operation, the deviation is the long converged within a predetermined range The control mode is switched, and the control mode is maintained if the deviation does not converge within a predetermined range .

  According to the above-described configuration, even when the control mode switching operation unit is switched, the control mode switching control unit controls the control command value input from the manual operation unit and the control input from the main control unit. Based on the deviation from the command value, it is determined whether or not to switch the control mode. For example, the initial value set in the manual operation unit is an abnormal value. In such a case, it is possible to avoid the occurrence of an inconvenient situation where the control mode is immediately switched.

  In the second feature configuration, as described in claim 2, in addition to the first feature configuration described above, the control mode switching control unit includes a control command value input from the manual operation unit, and the main control unit. The control mode is switched when the deviation from the control command value input from the control device converges to a predetermined range and the state is maintained for a certain time (for example, 5 seconds).

  According to the above configuration, the control mode is switched on condition that the deviation between the control command value input from the manual operation unit and the control command value input from the main control device converges to a predetermined range. The operator can operate the manual operation unit to set the control command value to a value close to the control command value input from the main control device, and then shift to the local control mode. The operating state of the plant can be maintained.

  In the third feature configuration, in addition to the first feature configuration described above, a control command value input from the manual operation unit and a control input from the main control device are provided. A guidance display unit is provided for guiding the manual operation unit to operate so that a deviation from the command value converges within a predetermined range.

  According to the above configuration, when the control mode switching unit is switched, even when the control command value input from the manual operation unit is significantly different from the control command value input from the main control device, Since the guidance display unit guides the operator so that it can be appropriately operated, the control mode can be quickly switched.

  In the fourth feature configuration, as described in claim 4, in addition to the second feature configuration described above, a control command value input from the manual operation unit and a control command input from the main control unit are provided. The control command value input from the manual operation unit is corrected so that the deviation from the value converges to a predetermined range.

  According to the above configuration, when the control mode switching unit is switched, even when the control command value input from the manual operation unit is significantly different from the control command value input from the main control device, Since the control command value input from the manual operation unit is corrected by the control mode switching control unit so as to approach the valve opening value input to the main controller, the control mode can be switched quickly. .

  In the fifth feature configuration, as described in claim 5, in addition to any of the first to fourth feature configurations described above, the control unit is housed in an explosion-proof structure, and control mode switching is performed. The operation unit and the manual operation unit are located outside the explosion-proof structure.

  According to the above-described configuration, even a valve control device incorporated in a plant having a risk of explosion or the like can be shifted to the local control mode and operated in a safe environment.

  As described above, according to the present invention, when the control mode switching unit is switched to either the remote control mode or the local control mode, a petrochemical plant that can maintain an appropriate operation state of the plant. A valve control device can be provided.

  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.

  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, 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 CU net (registered trademark of Step Technica Co., Ltd.). 30, control information, control parameters, display data, and the like are shared through the shared memory CM.

  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 mounted with a battery-backed SRAM 44, and is configured so that control information obtained by the control units 20 and 30 obtained via the shared memory CM is stored in a ring buffer format. A removable SD memory 46 for backup storage is mounted.

  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 an external personal computer via an explosion-proof casing C is provided.

  The infrared interface 43 communicates with the control unit 1 without opening the door of the casing C constituting the explosion-proof structure, sets various control parameters for initial setting, and includes control information and display data including abnormality information. It is provided to connect to a personal computer PC for maintenance that reads out the data and the like.

  Control parameters input from the maintenance personal computer PC are written to the shared memory CM via the microcomputer 41 of the display unit 40, and are similar to the shared memory CM mounted on another control unit board via the local network. Is written to.

  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.

  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 PC 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.

  More specifically, as shown in FIG. 8, when each control unit 20, 30 detects an operation input from the control mode switching operation unit SW2 (S1), the control command value input from the manual operation unit SW3 at that time And a control command value input from the main control unit CT, and when it is determined that the deviation is larger than a predetermined range (S2), the control mode is switched to its own shared memory CM while maintaining the control mode. The request message display request data is written (S3).

  When the display unit 40 detects the display request data of the guidance message copied to its own shared memory CM, the display unit 40 displays a guidance message for prompting the operation of the manual operation unit SW3 on the display screen of the color liquid crystal display unit 45 (S4). The guidance message includes an operation direction instruction of the manual operation unit SW3 indicating whether to increase or decrease the opening of the valve.

  The screen is input from the control mode display unit for identifying whether the current control mode is the local control mode or the remote control mode, the control command value input from the manual operation unit SW3, and the main control unit CT. The deviation from the control command value is displayed together with the guidance message.

  When the manual operation unit SW3 is operated by an operator who visually confirms the guidance message and the deviation and the deviation converges within a predetermined range, the display request data of the guidance message is deleted by the control units 20 and 30 (S2). At that time, the remote control mode is switched to the local control mode (S5, S6), or the local control mode is switched to the remote control mode (S5, S7).

  In the above flow, 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 larger than a predetermined range, the deviation is caused by the operation of the manual operation unit SW3. Although an example of convergence to the predetermined range has been described, the deviation may converge to the predetermined range due to a change in the control command value input from the main controller CT. In particular, when switching from the local control mode to the remote control mode is performed, the main control unit CT is configured to actively change the control command value by transmitting information to that effect to the main control unit CT. Is also possible. The main controller CT may be configured to output a control command value corresponding to the opening information of the valve 1 when the mode switching operation information is received.

  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.

  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.

  In the above-described embodiment, the case where the control unit that controls the valve V is redundantly controlled by the two control units has been described. However, the control unit may be configured to be redundantly controlled by three or more control units. In this case, a priority order can be set for each control unit, and a control right can be transferred from a control unit with a higher priority to a lower control unit.

  In the embodiment described above, an example in which two opening degree sensors S for detecting the opening degree of the valve V are provided has been described. However, three or more opening degree sensors S are provided, and each output is input to each control unit. You may comprise.

  In the embodiment described above, when 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 converges to a predetermined range, the control mode switching is performed. Although the example in which the control mode is switched by the control unit has been described, the deviation between the control command value input from the manual operation unit SW3 and the control command value input from the main control unit CT when the control mode is switched is within a predetermined range. The control mode switching control unit may be configured to correct the control command value input from the manual operation unit SW3 so as to converge.

  That is, when a switching operation is performed from the remote control mode to the local control mode, a positive or negative offset value is added to the control command value input from the manual operation unit SW3, and the control command input from the main controller CT. You may correct | amend so that it may become equal to a value.

  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 Flow chart showing control mode switching operation

1: control device 20, 30: control unit 21a, 31a: control mode switching control unit 40: display unit 41a: guidance display unit CT: main control device 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 (5)

A control unit for driving and controlling the valve based on a valve opening value input from an opening sensor and a control command value for the valve, and a remote for driving and controlling the valve based on a control command value input from a main controller Petroleum having a control mode switching operation unit capable of switching the control unit to any one of a control mode and a local control mode for driving and controlling the valve based on a control command value input from a manual operation unit A valve controller for a chemical plant,
A control command value input from the previous SL manual operating unit, based on a deviation between a control command value input from the main control device, the control mode switching control section for determining whether to switch the control mode before The control mode switching control unit switches the control mode if the deviation converges within a predetermined range when the control mode switching operation unit is switched, and the deviation is within the predetermined range. A valve control device for a petrochemical plant that maintains the control mode if it does not converge within .   The control mode switching control unit switches the control mode when a deviation between a control command value input from the manual operation unit and a control command value input from the main control device converges within a predetermined range. The valve control apparatus of a petrochemical plant according to 1.   A guidance display unit that guides the user to operate the manual operation unit so that a deviation between a control command value input from the manual operation unit and a control command value input from the main controller converges to a predetermined range. The valve control device for a petrochemical plant according to claim 2.   The control mode switching control unit is input from the manual operation unit so that a deviation between a control command value input from the manual operation unit and a control command value input from the main control device converges within a predetermined range. The valve control device for a petrochemical plant according to claim 2, wherein the control command value to be corrected is corrected. The petrochemical plant valve according to any one of claims 1 to 4, wherein the control unit is housed in an explosion-proof structure, and a control mode switching operation unit and a manual operation unit are installed outside the explosion-proof structure. Control device.

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