JPH11149301A - Automatic controller provided with duplexed detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller provided with detection parts switching the signals of detectors on a normal-side without passing a manual operation mode shift as much as possible when the abnormality of the detector occurs. SOLUTION: An automatic controller is provided with a first detector, and a second detector 2, first and second output signal lines 11 and 13 respectively connecting the first and second detectors 1 and 2 to a same switch 3, a circuit 31 for holding the signals after being switched of the first and second detection signals, abnormality judgment circuits 5 and 6 respectively provided for the first and second output signal lines 11 and 13, a circuit 7 which are connected to the first and second output signal lines 11 and 13, receive the signals of the first and second detectors 1 and 2 and detect the deviation of the signals and a temporary holding signal generation circuit 32 generating a signal for temporarily holding an automatic control circuit when the deviation is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic control device for performing control operation by measuring a state quantity with a duplicated detector in various plants and apparatuses, and in particular, to a duplicated detection while continuing automatic control. The present invention relates to an automatic control device for switching containers.

[0002]

2. Description of the Related Art In control devices of various plants and the like, automatic control mainly based on feedback control based on a detection signal of a state quantity of an object to be controlled is widely used. Since the control operation is not suitable for automatic control, manual operation by an operator is also used. As shown in FIG. 4, a typical feedback control in a plant and an apparatus includes a detection unit 41 of a detector 45, a control unit 42, an operation unit 43, and a manual setting unit 44.

[0003] The state quantity of the control object detected by the detector 45 is taken into the detection unit 41, and the control unit 42 removes noise, an abnormal signal and the like and sends only the signal of the normal detector 45 as a detection signal to the control unit 42. The control section 42 takes in the detection signal and adjusts the output signal of the controller so as to have a predetermined set value. The output signal of the control unit 42 is sent to the operation unit 43 to move the operation end 47. If the detection unit 41 determines that there is no normal detection signal, the control unit 42 cannot continue the control. Therefore, the output signal to the operation unit 43 is set via the changeover switch 46 to the manual setting unit. Switch to signal from 44. The switched state is generally called a “manual mode”, and the operator directly operates the operating terminal 47.
To control the adjustment.

Therefore, in the above-mentioned feedback control system, when the detector 45 fails, normal automatic control cannot be performed. Therefore, two identical detectors are provided at the same place.
Automatic control is performed until a failure occurs in the detector, and if a failure occurs, the mode is temporarily shifted to the manual mode, and after a manual switch to the detector on the normal side, automatic control is restarted again. .

FIG. 2 shows a control circuit of the detection unit 41 of the conventional duplex system. In FIG. 2, the same detectors 1, 2
Are connected to the signal switch 3 via the output signal lines 11 and 13, respectively, and the signal switch 3 sends the selected detection signal to the control unit 42. First, the detection signals from the detectors 1 and 2 enter the comparative upper and lower limit detector 7 via the output signal lines 11 and 13, respectively, so that even if the detector abnormality signals (B) and (C) are not output, both signals are output. If there is a difference (deviation) greater than or equal to a predetermined value between the detectors 1 and 2, the on-delay timer-1
After the time set at 5, the detector abnormal signal (D) is output.

Further, when the detector abnormality signals (B) and (C) are not output and there is a difference (deviation) between the two detectors 1 and 2 exceeding a predetermined value, the AND gate 62 and the inverting circuit A deviation signal is output by 51 and 52, and a detector abnormality signal (D) is output after the time set by the on-delay timer-15, and the mode shifts to the manual mode.

On the other hand, detection signals from the detectors 1 and 2 enter the upper and lower limit detector 5 and the sudden change detector 6 via output signal lines 11 and 13, respectively.
Is detected. That is, the upper and lower limit detector 5 outputs an output signal when the detection signal is out of the preset range, and outputs an output signal when the sudden change detector 6 also detects a sudden change in the detection signal. These output signals are the detector 1,
When the signal is output every two, detector abnormality signals (B) and (C) are output via the OR gates 61 and 60.

When a detector abnormal signal (B) is issued when the detector 1 is selected by the switch 3, a detector abnormal signal is output when the detector 2 is selected by the switch 3. When (C) is issued and when the detector abnormality signal (D) is issued, it is determined that an abnormality has occurred in the detector, and the automatic control is interrupted to shift to the manual mode. Here, which of the detectors 1 and 2 is selected depends on whether or not the detector 1 selection signal A is established.

That is, in the figure, when the selection signal (A) of the detector 1 is established in the switching unit 3, the AND gate 63 takes the AND of the abnormal signal (B) and the selection signal (A). Move to manual mode. When the selection signal (A) of the detector 1 is not established in the switch 3, in other words, when the detector 2 is selected by the switch 3, the abnormal signal (C) is output by the AND gate 64 and the inverting circuit 53. ) And the inverted selection signal (A) are ANDed to shift to the manual mode.

In manual operation, the detector abnormal signal (B),
(C) is input to the corresponding AND gates 65 and 66 via the inverting circuits 54 and 55, respectively. Therefore, when the detector abnormal signal (B) is not output, the detector 1 is manually operated. When the selection is made, the selection signal (A) of the detector 1 is output via the signal establishment device 17, and when the detector abnormality signal (C) is not output, the detector 2 is selected manually. As a result, the selection signal (A) of the detector 1 is not output via the signal establishment unit 17, in other words, the detector 2 is selected.

Therefore, according to the above-described conventional control method, when an abnormality occurs in any of the detectors 1 and 2, the operation is shifted to the manual operation, and the automatic control is not continued. Therefore, only when there is no difference between the signals of the detectors 1 and 2 before a predetermined time and when it is possible to automatically determine which of the detectors 1 and 2 is abnormal, In a limited manner, a control method has been put to practical use in which a control device can automatically select and switch a detection signal to be sent to a controller without manual operation.

The control method will be described with reference to FIG. 3, the same reference numerals as those in FIG. 2 denote the same functional circuits or members. In the figure, reference numeral 20 denotes an automatic switching permission determination circuit which calculates a difference between the detector 1 and the detector 2 before a predetermined time by a subtracter 21 and a dead time delay element 23, and sets a difference preset by an upper / lower limit detector 25. The automatic switching signal (E) is output only when no error occurs. And the automatic switching signal (E)
Is output, the selection signal (A) of the detector 1 is output via the AND gate 67, the OR gate 69, and the signal generator 17 when the detector abnormality signal (C) is output,
Conversely, when the detector abnormal signal (B) is output, the AND gate 68, the OR gate 70, and the signal generator 1
7, the selection signal (A) of the detector 1 is not output,
In other words, the detector 2 is selected.

[0013] Therefore, such a conventional technique uses the upper and lower limit detector 2.
5 is a method in which an automatic switching signal (E) is output only when a preset difference has not occurred, and switching is performed by the switch 3 while automatic control is continued. However, even when this method is used, the chance of automatically switching the detection signal does not increase dramatically.

[0014]

As described above, when two detectors 1 and 2 are used in a duplex system, it is rare that these two detectors become abnormal at the same time. If one detector 1 becomes abnormal and the other detector 2 is normal, automatic control can be continued by selecting and using the signal of the normal detector 2 and immediately selected by the switch 3 What is necessary is just to switch a signal.

However, this has the following problem.
That is, by the time the detection signal of the abnormal detector 1 is determined to be abnormal, the value may be considerably different from the normal detection signal of the detector 2. Detector 1
Is automatically controlled based on the signal of the detector 1 until it is determined that there is an abnormality. Therefore, there is a possibility that the operating device is considerably away from a normal position. Therefore, when the automatic control is switched to the one based on the detection signal of the detector 2 when the abnormality of the detector 1 is determined, the operation end 47 is forcibly pulled back to the position based on the normal detection signal, Disturbances are continuously applied to the control system, which greatly impairs the stability of the control system. Therefore, as described above, even if the detector is duplicated, if the detector becomes abnormal, it is a general method to temporarily shift to the manual mode as shown in FIG. Alternatively, as shown in FIG. 3, automatic switching is performed without manual operation only when there is no difference between the detection signals of both detectors until a predetermined time ago.
The chance of automatically switching the detection signal does not increase dramatically.

However, in the above-mentioned conventional control method, it is extremely burdensome for an operator to perform an appropriate manual operation at the time of occurrence of an abnormality whose occurrence is unknown. Therefore, the present invention, when a detector abnormality occurs, without going through the manual mode as much as possible,
It is an object of the present invention to provide a control device including a detection unit that switches to a signal of a normal detector.

[0017]

In order to solve the above problems, the present invention provides a first detector 1 and a second detector 2, as shown in FIG. A first and second output signal lines 11 and 13 for connecting the detectors 1 and 2 to the same switch 3, respectively; a circuit 31 for holding a signal after switching the first and second detection signals; , The abnormality determination circuits 5 and 6 provided on the first and second output signal lines 11 and 13, respectively, and the first and second detection circuits connected to the first and second output signal lines 11 and 13 respectively. And a temporary holding signal generating circuit 32 for generating a signal for temporarily holding the automatic control circuit when a deviation occurs. Be composed.

According to this invention, the state of various plants and devices is measured by the duplicated detector, and the controller calculates the control amount so that the control amount measured by one of the detectors becomes the target set value. In the automatic control device that adjusts the operating device with its output, if one of the duplicated detectors fails, the operating device fluctuates even if switching to the other detector with automatic control continued. Thus, it is possible to obtain a switching control method that does not cause disturbance in various plants and devices.

Some recent detectors have a so-called self-diagnosis function in which the detector itself detects that the detector has failed. When the detector determines a failure (abnormality) by self-diagnosis, a signal out of a predetermined signal range is output to the automatic control device, so that the automatic control device detects the signal based on the detector abnormality signal described above. You can know the abnormality of the vessel. By incorporating such advances on the detector side, the scope of the present invention is further expanded. or,
The first and second output signal lines are required when performing a wired connection. However, when the detector has an abnormality determination function in self-diagnosis or when transmitting and receiving signals wirelessly, the first and second output signal lines are required. No second output signal line is required.

Therefore, according to the first aspect of the present invention, the state of various plants and equipment is measured by the duplicated first and second detectors, and the control amount measured by one of the detectors is set as a target. An automatic control device that performs an operation with a controller so as to be a value and adjusts an operation device with an output thereof, a switch that switches an output signal of the first and second detectors,
A signal holding circuit for holding a signal after switching between the first and second detection signals, an abnormality determination circuit for determining abnormality of each of the first and second detectors, A deviation detecting circuit for detecting a deviation between output signals of the detector, and a temporary holding signal generating circuit for generating a signal for temporarily holding the automatic control circuit when the deviation is present. Features.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. However, the types of components and circuits described in this embodiment and the relative arrangement thereof are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. . FIG. 1 shows a control system according to an embodiment of the present invention.
FIG. 5 is a circuit diagram of a part particularly corresponding to the detection unit in FIG. 4. In the following description, the same functional parts shown in FIGS.
The same symbols are used for understanding the present invention. In FIG. 1, detectors 1 and 2 are connected to a switch 3 via output signal lines 11 and 13, respectively. Switch 3
The control unit 4 selects one of the detection signals output from the detectors 1 and 2 in a form to be described later, and performs a control operation on this.
2 (see FIG. 4). The upper and lower limit detector 5 and the sudden change detector 6 are connected to the output signal lines 11 and 13, respectively.

The range of the controlled variables to be detected by the detectors 1 and 2 can be reasonably predicted depending on the operating conditions of the plant and the equipment. Therefore, the range of the value of the detection signal corresponding to the fluctuation range is set as the signal range, and the detection signal outside the signal range can be determined as abnormal by the upper and lower limit detector 5. Further, the speed of the change of the control amount can be predicted within a predetermined range. Therefore, the sudden change detector 6 compares the degree of change of the detection signal, for example, its differential value with the set value, and can judge that it is abnormal if it is larger. These abnormality detection circuits 5 and 6 are determined in consideration of characteristics of a control amount of a plant and an apparatus in which the detectors 1 and 2 are used.

The upper and lower limit detector 5, the sudden change detector 6
The output signal of the OR gate 6 is divided for each of the detectors 1 and 2.
Detector abnormality signals (B) and (C) are transmitted through 1 and 60. Then, the abnormality of any of the detectors 1 and 2 can be determined based on the output of the detector abnormality signals (B) and (C).

On the other hand, the comparison upper and lower limit detector 7 includes the detector 1,
2 are constantly compared via the output signal lines 11 and 13. If the deviation between the two detection signals exceeds a predetermined set value, the detector abnormality signal (B),
Inverting circuit 5 even when (C) is not output
1 and 52, and a deviation signal is output via the AND gate 62. If the deviation signal continues to be output even after the time set by the on-delay timer 15 has elapsed, one of the detections is performed. And outputs an abnormal signal (D) indicating that the units 1 and 2 are abnormal. At this point, (B),
Since the detector abnormality signal of (C) is not output, abnormality of any of the detectors 1 and 2 is not determined.

That is, it is not possible to immediately judge which of the detectors 1 and 2 is abnormal only when a deviation occurs between the detectors 1 and 2. Therefore, when a deviation occurs between the detectors 1 and 2 by the comparison upper / lower limit detector 7, the control output fixing command (F) is sent to the switch 31 via the one-shot timer 32, and is sent to the control unit 42. The detection signal to be sent is fixed and held. That is, the detection signal is held by passing the signal after switching to the switch 31, and by holding the signal, control is performed using the signals of the detectors 1 and 2 on the abnormal side, and the operating device is moved to the normal position. You will never leave.

However, since the detection signal sent to the control unit 42 is held, the automatic control is continued during that time, but the operating device is not controlled to be adjusted according to the control amount. Therefore, the time of the one-shot timer 32 that can hold the signal sent to the control unit 42 is appropriately determined depending on the plant and the control target of the apparatus. If the detector abnormality signals of (B) and (C) are not output during the holdable time and the abnormal detector cannot be determined, the detector abnormality signal (D) is established as described above, and the control is performed. The system goes into manual mode. This case is conventional and cannot be switched automatically with current technology.

Next, an abnormal detector can be determined, and the switch 3
A circuit for avoiding disturbance to the operation device even when the detection signal is switched in the following will be described. Since the time of the on-delay timer 15 is much shorter than the predetermined holding time by the one-shot timer 32, the detector abnormality signal (D) is established almost simultaneously after the control output fixing command (F) is established in the control unit 42. . In response to the control output fixing command (F), the control unit 42 outputs an output signal to the operation unit 43 to the one-shot timer 3.
2 for a predetermined holding time.

The upper / lower limit detector 5 or the sudden change detector 6 is set within the holding time of the detection signal of the one-shot timer 32 described above.
In the case where an abnormality in any of the detectors 1 and 2 is determined by the circuits 5 and 6, the switch 3 selects a normal signal. At the same time, when the detector abnormality signal (B) or (C) is established, the AND gate 62 becomes (D)
(B) and (C) by the inverting circuits 51 and 52 together with the signal.
, The detector abnormality signal (D) becomes unsatisfied, and immediately thereafter, the output of the one-shot timer 32 also becomes unsatisfied, and the signal of the switch 31 changes the signal of the switch 3 A normal detector signal is sent to the control unit 42 by passing through. Further, immediately after the switching unit 31 passes the signal of the switching unit 3, the control output fixing command (F) is not satisfied, and the control output of the control unit 42 is released and the holding of the operating device is released.

By performing the above-described switching in series, it is possible to prevent the operation device from being unnecessarily fluctuated in the process of switching the detection signal to the normal side, thereby preventing disturbance to the plant and the apparatus. Of course, these operations
Since the operation is performed without the intervention of the operator, the burden on the operator is reduced.

[0030]

As described above, according to the control method of the present invention, when an abnormality occurs in one of the two detectors, the detection to the control unit is performed until the abnormal side detector can be specified. By temporarily holding the signal and the signal to the operation device, disturbance to the control target such as the plant and equipment can be reduced, and automatic control can be continued without switching the operation device to the manual mode. Therefore, the reliability and safety of a control target such as a plant can be improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a control system according to an embodiment of the present invention, particularly a portion corresponding to a detection unit in FIG.

FIG. 2 is a conventional circuit diagram of a portion corresponding to a detection unit in FIG. 4;

FIG. 3 is another conventional circuit diagram of a portion corresponding to the detection unit of FIG. 4;

FIG. 4 is a block diagram showing a typical feedback control system.

[Explanation of symbols]

 1, 2 detector 3 switch 5 upper / lower limit detector 6 sudden change detector 7 comparison upper / lower limit detector 11, 13 output signal line 15 on-delay timer 17 signal fulfillment unit 31 switch 32 one-shot timer 41 detection unit 42 control Section 43 Operation section 44 Manual setting section A Detector 1 selection signal B, C, D Detector abnormal signal E Automatic switching permission signal F Control output fixed command

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Katsumi Kishimoto 2-1367 Soga-cho, Chuo-ku, Chiba-shi, Chiba Chiba Thermal Power Plant (72) Inventor Yoshiyuki Kita 2-chome, Arai-machi, Takarai City, Hyogo Prefecture No. 1-1 Inside Takasago Works, Mitsubishi Heavy Industries, Ltd. (72) Inventor Hiroya Kumeyama 3-3-1 Minato Mirai, Nishi-ku, Yokohama-shi MDS Co., Ltd.

Claims (1)

[Claims] 1. The state of various plants and equipment is measured by duplexed first and second detectors, and the controller is controlled so that the control amount measured by one of the detectors becomes a target set value. An automatic control device for performing an arithmetic operation and adjusting an operating device with an output thereof, comprising: a switch for switching output signals of the first and second detectors; and a signal after switching of the first and second detection signals. Signal holding circuit for holding an error, an abnormality determination circuit for determining an abnormality of each of the first and second detectors, and a deviation detection for detecting a deviation between output signals of the first and second detectors Circuit and
And a temporary holding signal generating circuit for generating a signal for temporarily holding the automatic control circuit when the deviation occurs. An automatic control device having a duplicated detector.