JP2985424B2 - Controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller used for controlling a process or the like, and more particularly to a controller using a full-dot display on the front side to display various information for control operation. The present invention relates to a highly-reliable controller that takes into account failures in control operation means, a display, and its display control means.

[0002]

2. Description of the Related Art Conventionally, a single-loop controller using a microprocessor has been widely put into practical use. Such a single-loop controller is a distributed control system (DC
Compared with S), there is an advantage that the engineering burden is small and the operability is good. The conventional single-loop controller has an operation panel on the front face thereof which displays information necessary for control (process amount PV and control output MV), as shown in, for example, Japanese Patent Publication No. 57-57721. An operation key for changing the set value and an operation key for changing the adjustment mode (automatic adjustment mode, manual adjustment mode, etc.) are arranged, and various parameters for control calculation and designation of various functions are arranged. , Correction calculation, etc., are provided on the side of the instrument.

[0003]

Such a conventional controller has a feature that it can maintain the same operability as an analog controller, but various parameters can be set by pulling the meter out of the rack and putting it on the side. There was a problem that the provided setting means had to be operated. In addition, the panel on the front of the instrument was only provided with the minimum indicator and operation keys required for control, so it was necessary to pull out the instrument for parameter setting, etc., which was inconvenient to handle. . The present invention has been made in view of these points, and enables various types of operation information necessary for performing a control operation of a process to be displayed on a controller front panel having a limited area. It is an object of the present invention to provide a highly reliable controller capable of performing a backup even when a display system for displaying various information fails.

[0004]

According to the present invention for achieving the above object, there is provided a control operation means for inputting a process amount and performing a predetermined control operation, a display provided on a front surface of a controller, and a process amount. Display control means for inputting a control output value and a control output value for displaying these values on the display, and manually adjusting the control output value while monitoring the control output value displayed on the display. Manual adjusting means, a function of inputting a signal from the control arithmetic means and a signal from the manual adjusting means and holding these signals, an output means having a function of sending a control output to the process side, A manual backup means whose output is adjustable and sends a manual backup signal in a position type output form; a signal from the output means and a manual backup signal from the manual backup means A manual selector switch which selects a signal and sends it to the process side is provided, adjusting a display portion
So that it can swing up in front of the moderator
As well as manual backup
Operation is possible from the front of the controller
This is a controller characterized by being installed behind a display unit .

[0005]

The display displays various operation information necessary for the control operation and its monitoring. The controller cannot perform a normal control operation even if the control operation means fails or the display control system including the display unit fails. When such a state occurs, the manual backup unit sends a manual backup signal to the process side via the manual changeover switch. This makes it possible to maintain high reliability.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration block diagram showing one embodiment of the present invention. In the figure, reference numeral 1 denotes a control operation means for inputting a process amount PV and performing a predetermined control operation, and includes an A / D converter for converting an input analog signal into a digital signal, and a microprocessor for performing a control operation such as a PID operation. It is comprised including. Reference numeral 2 denotes a display provided on the front of the controller and capable of displaying characters, figures, and the like. For example, a full-dot liquid crystal display with a backlight is used. Reference numeral 3 denotes a display control unit for inputting the process amount PV, the control output amount MV, and the like, and displaying these values on the display 2. The display control means 3 is configured to operate independently of the control calculation means 1 and has a process amount PV
A / D converter for converting an analog signal such as a control output amount MV or the like into a digital signal, a function for creating various screens to be displayed on the display unit 2, various functions provided on a front panel of the controller. The microprocessor includes a microprocessor having a function of receiving a signal from the operation key, and transferring the signal to the control operation unit 1 or reflecting the signal on information displayed on the display.

Reference numeral 4 denotes a manual adjusting means for manually operating an operation key (MV operation key) provided on the front panel of the controller while monitoring a control output (MV display) displayed on the display 2. Thus, the control output value MV can be adjusted. 5 is the control output MVa
Output means for sending out to the process side, the result of calculation output from the control calculation means 1 is held, and the hold value can be increased or decreased by a signal from the manual adjustment means 4 (signal from the MV operation key). Digital hold circuit configured, D / A for converting the value into an analog signal
It includes a converter and the like. Here, as the digital hold circuit, for example, an up / down counter having a function of latching a digital operation result from the control operation means 1 and a function of increasing / decreasing a hold value at a constant speed by a signal from the MV operation key is used. Used. Reference numeral 6 denotes a manual changeover switch for selecting one of the control output MVa from the output means 5 and a manual backup signal MVb to be described later and sending it to the process side. The manual changeover switch 6 is normally located at a position for selecting the control output MVa from the output means 5, and is driven to the opposite position by the operator during manual backup. The switch status indicating the switching position of the manual changeover switch 6 is applied to the control calculation means 1. Reference numeral 7 denotes a voltage / current signal conversion circuit for converting a voltage signal passed through the manual change-over switch 6 into a current signal, which is not necessary when outputting as a voltage signal.

Reference numeral 8 denotes a manual backup means for transmitting a manually adjusted backup signal MVb to the process side via the manual changeover switch 6 at the time of manual backup. The manual backup means 8 is provided with a scale 80, for example, in the range of movement of the brush position, and includes a potentiometer 81 capable of changing the value of the manual backup signal MVb using the scale as a guide.
82 is a control output signal MVa output from the output means 5
A coincidence detection circuit for detecting coincidence with the backup signal MVb output from the potentiometer 81. Reference numeral 83 denotes a display lamp which is turned on by an output signal of the coincidence detection circuit 82. The backup signal MVb output from the potentiometer 81 is applied to the control calculation means 1. 9
Is a monitoring means for monitoring the operation of the control operation means 1, and is constituted by, for example, a watchdog timer. When the control operation means 1 is abnormal, it is transmitted to the display control means 3 and the output means 5.

FIG. 2 is a plan view showing the front surface of the instrument of the controller. Here, a case where an operation screen is displayed on the display 2 is shown. In the operation screen displayed on the display 2, the measured value PV is displayed in the vicinity of the center of the screen as a bar graph BG1 which expands and contracts in the vertical direction according to the value, and the control output is displayed on the lower side of the screen. The MV is displayed as a bar graph BG2 so that the MV expands and contracts in the left-right direction according to the value. In the bar graph showing the control output MV, the sign “C” on the left side means that the control output MV becomes small and the valve is closed, for example, and the sign “O” on the right side indicates that the valve is closed. It means that it is opening direction. The set value SV is displayed as a triangular instruction mark MK in association with the same scale SL as the bar graph BG1 indicating the measured value PV. The position of the instruction mark is changed by changing the set value (operation of the operation keys KY4 and KY5).
Together with the scale SL. Such a display form simulates the front panel surface (instrument diagram) of a conventional controller, and is considered so that even an operator who is familiar with the conventional controller can monitor and operate the control operation status without feeling uncomfortable. I have. In the driving screen, P
The V value, SV value and MV value are also displayed as digital numerical values. The tag number (TIC-) assigned to the control loop assigned to this controller is displayed at the top of the screen.
1000) is displayed. According to such an operation screen, when monitoring away from the controller, the main data, ie, the PV value, the SV value, and the MV value, can be recognized in an analog display. Typical numerical values can be recognized on a digital display.

On the keyboard KB, an operation key KY1
To KY3, a function for switching the operation mode is allocated. When the operation key KY1 is pressed, the set value SV is given from the host computer to the host computer operation mode in which the control operation is performed. Pressing KY2 sets the automatic operation mode in which the controller performs the control operation by itself, and pressing the operation key KY3 sets the manual adjustment mode in which the control output MV can be adjusted manually. Functions for setting the set value SV are assigned to the operation keys KY4 and KY5, and the set values can be changed by pressing these operation keys. This set value can be recognized as the position of the set value mark MK on the display 2. The operation keys KY8 to KY10 are assigned with a function for changing the control output MV when switched to the manual adjustment mode. That is, when the mode is switched to the manual adjustment mode, signals from these operation keys are given to the manual adjustment means 4. here,
Pressing the operation key KY8 decreases the control output MV,
The control output MV can be increased by pressing the operation key KY10. Also, the operation key KY8 or K
By simultaneously pressing Y10 and the operation key (speed-up key) KY9, the speed of decrease or increase of the control output MV is increased so that the desired control output value can be quickly changed.

FIG. 3 is a conceptual diagram showing the relationship between the front panel on which the display 2 is provided and the installation position of the manual backup means 8. The instrument front panel provided with the display 2 and the keyboard KB is as shown in FIG. 2 in a normal control operation state, but in a manual backup state, as shown by an arrow a, the front panel surface (display part)
Is configured to be able to swing up. When the front panel surface is swung up, the manual backup means 8 appears at the back (behind the display portion), and the manual switch 6 and the wheel 84 for moving the brush of the potentiometer 81 can be operated from the front. It has become. In addition, communication connectors 91 and 92 that enable connection with external devices are also shown.

The operation of the apparatus constructed as described above is divided into a normal control operation, a control operation unit 1 failure, a display control unit 3 failure and an output unit 5 failure.
Each operation will be described. (During normal control operation) The control calculation means 1 performs a control calculation operation as a controller. That is, the control operation means 1
Performs PID control calculation on the deviation between the process amount PV and the set value SV set by the SV operation keys KY4 and KY5, and outputs the calculation result to the output means 5. The output means 5 holds the calculation result, converts the result into a digital signal, and outputs the result to the process side via the manual changeover switch 6 and the V / I conversion means 7. The display control means 3 receives the display information from the control operation means 1 and displays, for example, PV or M
V is displayed as a bar graph and a digital value. Also, the on / off state of various operation keys is transmitted to the control calculation means 1. Here, when an on / off signal is received from the SV operation keys KY4 and KY5, the mark M indicating the set value SV is received.
K is moved and displayed, and the set value SV indicated by the mark MK is applied to the control calculation means 1.

(At the time of failure of the control operation means 1) The failure of the control operation means 1 is detected by the monitoring means 1, and the abnormality detection signal is given to the output means 5 and the display control means 3. When the output means 5 receives the abnormality detection signal, the output means 5 inhibits the latch input from the control operation means 1 and makes the internal up / down counter (register) accessible by the signal from the manual adjustment means 4. The display control means 3 ignores the access from the control calculation means 1 and converts the process amount PV and the control output MVa into digital signals using its own A / D converter, and converts them into a digital signal. 2 is displayed as a bar graph and a digital value. Therefore, the operator views the MV display bar graph and the MV value displayed on the display device 2 while watching the MV operation keys KY8 to KY8.
By pressing KY10, the value of the up / down counter in the output means 5 can be changed, and the control output MVa can be manually operated. As a result, even if the control calculation means 1 fails, the control output value MVa is automatically held, and can be manually operated using the manual adjustment means 4.

(Failure of display control means 3 or output means 5)
When the display control means 3 fails, the control output value M
Since Va is no longer displayed, manual operation by the manual adjusting means 4 cannot be performed. Similarly, when the output means 5 fails, the manual operation by the manual adjustment means 4 and the control operation by the control calculation means 1 cannot be performed. To cope with such a worst case, the operator will switch to the manual backup state. The switching to the manual backup state is performed by first swinging up the front panel surface as shown by an arrow a in FIG. 3 and activating the manual backup means 8 installed at the back. That is, in this state, when the manual switching switch 6 is turned on (a state in which the output MVb of the manual backup means 8 is selected), the manual backup signal MVb from the manual backup means 8 is output to the process side via the changeover switch 6. Will be done. Then, the value of the manual backup signal MVb can be adjusted by the wheel 84 using the value of the scale 80 as a guide and can be manually operated.

Here, when switching to the manual backup state (when turning on the manual switching switch 6), the output MVb of the manual backup means 8 does not match the control output MVa that has been output until then. However, there is a risk that the output output to the process side may change suddenly. The coincidence detection circuit 82 and the indicator lamp 83 in the manual backup means 8 are provided to eliminate such danger. That is, prior to turning on the manual switching switch 6, turning the wheel 84 and turning on the manual switching switch 6 with the display lamp 83 turned on, the output MVb of the manual backup means 8 will be It matches the output control output MVa (MVb =
MVa), and the switching to the manual backup state can be performed by the press. Note that the coincidence detection circuit 82 may be configured to change the light emission intensity of the display lamp according to the difference between MVb and MVa.

When the manual backup means 8 is in the manual backup state, the switch status of the manual switching switch 6 and the manual backup signal MVb are applied to the control arithmetic means 1, and the operation of the control arithmetic means 1 is normal. In this case, the control operation means 1 outputs the control output M to the output means 5
Va operates so as to follow the value of the manual backup signal MVb. Thus, even if the state is switched from the manual backup state to the normal control operation state (the manual changeover switch 6 is switched from the state where the manual backup signal MVb is selected to the state where the output signal MVa of the output means 5 is selected). ), The operation signal output to the process side does not change suddenly, and the switching can be performed by bumpless.

In the above-described embodiment, the case where the operation screen used for performing the control operation is displayed on the display 2 is shown. Trend graph showing past transition of PV, alarm screen showing alarm information, control operation means 1
It is possible to display a tuning screen for setting various parameters used by the controller, an engineering screen for setting an environmental level such as a type of various signals and a type of communication handled by the controller, and the like. Although a controller that handles one process amount PV is illustrated here, the present invention may be applied to a controller that performs cascade adjustment or selector adjustment by inputting two or more process amounts.

[0018]

As described above in detail, according to the present invention, even if the control operation means fails, the control by the manual adjustment means is possible if the display control means is operating normally. Further, even when the display control means or the output means fails, the manual operation can be performed by the manual backup means, and a highly reliable controller can be provided. Further, various operation information necessary for performing the control operation of the process can be displayed on the front panel of the controller having a limited area, so that a controller with good operability can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing one embodiment of the present invention.

FIG. 2 is a plan view showing an instrument front surface of the controller.

FIG. 3 is a conceptual diagram illustrating a configuration of a front panel on which a display is provided and the installation position of a manual backup unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control calculation means 2 Display 3 Display control means 4 Manual adjustment means 5 Output means 6 Manual changeover switch 8 Manual backup means 9 Monitoring means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-200305 (JP, A) JP-A-60-207903 (JP, A) JP-A-63-58501 (JP, A) 66402 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) G05B 9/02 G05B 7/02

Claims (1)

(57) [Claims] 1. A control operation means for inputting a process amount and performing a predetermined control operation, a display provided on a front surface of a controller, and a process amount and a control output amount are inputted, and these values are displayed on the display. Display control means for displaying on the display, manual adjustment means capable of manually adjusting the control output value while monitoring the control output value displayed on the display, and a signal from the control calculation means. An output means having a function of inputting signals from the manual adjustment means and holding these signals, and a function of sending a control output to the process side; and an output capable of being manually adjusted and having a position type output form. A manual backup means for transmitting a manual backup signal; a signal from the output means and a manual backup signal from the manual backup means selected and transmitted to the process side A dynamic changeover switch is provided, the display section
It is configured to be able to swing up in front of the controller
The manual backup means and switch the display unit.
The controller can be operated from the front with the
A controller that is installed behind a display unit .