JPS6115441B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic/manual switching device for a controller, and is capable of mutually switching between the automatic output of the controller and the manual output from the manual operation section without bumping or balance. The purpose of this invention is to provide an automatic/manual switching device for a controller.

In order to achieve such an objective, the present invention
During manual operation, the difference between the manual output value and the controller's automatic output value is held in a capacitor, and when switching from manual to automatic, discharge starts and the automatic output value (automatic operation Embodiments of the present invention will be described in detail below based on the drawings.

FIG. 1 is a block diagram showing an embodiment of an automatic/manual switching device for a controller according to the present invention. In the figure, OA ₁ corresponds to the automatic operation signal V _A , which is the output signal of the controller that produces the output after performing the desired calculation on the deviation between the measured value from the process and the set value, and the operation amount from the operation unit OP. The first differential amplifier _OA2 amplifies and outputs the difference input from the manual operation signal _VH , which is a feedback signal, and the input is input from the output of the first differential amplifier _OA1 via the switch _SW1 . The second differential amplifier, OA ₃ , which amplifies and outputs the difference input from the output, outputs the automatic operation signal V during manual adjustment.
A third differential amplifier that amplifies and outputs the difference input between _A and a voltage held in a capacitor (described later);
OA ₄ is a fourth differential amplifier that amplifies and outputs the difference input between the output of the third differential amplifier OA ₃ and the manual operation signal V _H . _R1 is a resistor connected between the connection point between the switch _SW1 and the (10) input terminal of the second differential amplifier _OA2 , and _R2 is the resistor connected between the output terminal of the second differential amplifier _OA2 and the The variable resistor SW 2 is connected between the (-) input terminal of the second differential amplifier OA ₃ and the second differential amplifier OA _{2 .}
This switch SW 2 is connected between the output end and the (-) input end of the switch, and this switch SW ₂ , together with the above switch SW ₁ , is configured to be "closed" when in manual mode, and "open" when switching from manual to automatic mode. has been done. C is a hold resistor connected to the output terminal of the second differential amplifier OA ₂ and connected between the connection point between the variable resistor R ₂ and the (-) input terminal of the third differential amplifier OA ₃ and ground. Together with the switch _SW2 , these capacitors constitute a hold circuit that holds the output of the first differential amplifier _OA1 in the capacitor C during manual adjustment.

These receive a controller output signal that generates an output by performing a desired calculation on the deviation between the measured value and the set value from the process, and a feedback signal corresponding to the manipulated variable, and when making manual adjustments, the difference signal is output. The capacitor C is held in the capacitor C, and during automatic adjustment, the capacitor C is discharged a certain amount at a time, and when it is fully discharged, it is maintained in that state, and the above feedback is obtained from the voltage difference between the output signal of the controller and the terminal voltage of the capacitor C. Obtained by subtracting the signal (subtracted)
It constitutes a means for outputting a signal related to the signal.

MO is a manual operation unit that outputs an automatic/manual switching signal H/A and manual operation signals MS ₁ MS ₂ . SW ₃ to _{SW 5} are automatic/manual changeover switches controlled by the automatic/manual changeover signal H/A from the manual operation unit MO, and PD indicates whether the output of the fourth differential amplifier _OP4 is positive or negative. A polarity discrimination circuit that outputs an up (UP) signal or a down (DOWN) signal and outputs the absolute value of the fourth differential amplifier _OA4 . A voltage/frequency converter that generates a frequency signal proportional to the input voltage from ₄ , a manual clock generation circuit that generates a clock signal that regulates the time (speed) required for the CLK operation unit OP to equilibrate, and a manual clock generator that generates a frequency signal proportional to the input voltage from CNT. a reversible counter that counts the clock signal CLOCK input through the automatic/manual changeover switch _SW4 based on the up signal UP and down signal DOWN inputted through the manual changeover switches _SW3 and _SW5 ;
D/A is a D/A converter that converts the digital signal from the reversible counter CNT into an analog signal, and V/A converts the digital signal from the reversible counter CNT into an analog signal.
P is an electric/pneumatic converter that converts the voltage from the D/A converter D/A into air pressure, and these convert the output from the above output means and the manual operation signal from the manual operation unit MO.
Automatic/manual switching switch for MS ₁ and MS ₂ SW ₃ to _{SW 5}
It constitutes a means for receiving the manipulated variable via the controller and transmitting the manipulated variable for driving the operating end.

The voltage/frequency converter V/F is configured to apply a pulse frequency signal proportional to the absolute value of the output of the fourth differential amplifier _OA4 to the reversible counter CNT as a clock signal CLOCK. Here, the reason why the clock frequency is not set to a fixed frequency is that the clock frequency in manual and automatic modes generally differs for convenience of operation, and in automatic mode, it is necessary to reduce the frequency of overshoot in the equilibrium state (V _A = V _H ). This is to minimize wear on the operating part OP.

Next, the operation of the embodiment shown in FIG. 1 will be explained with reference to FIG. 2. First, when in “manual operation”,
Automatic/manual changeover switches SW ₃ to _{SW 5} are manual operation parts
It is controlled by the automatic/manual switching signal H/A from MO and is on the manual side H. On the other hand, switches SW ₁ and SW ₂
is “closed” during manual operation. Therefore, the operating section OP is the manual operating section MS ₁ from the manual operating section MO,
It is controlled by a pneumatic signal obtained based on the UP signal UP/DOWN signal _MS2 and the clock signal CLOCK from the manual clock generation circuit CLK, and drives, for example, an operating valve. At this time, an analog signal (manual operation signal V _H ) corresponding to the valve opening degree is input from the operating section OP to the first differential amplifier OA ₁ as a feedback signal.

A first differential amplifier OA ₁ amplifies and outputs the difference input between the automatic operation signal V _A and the manual operation signal V _H.
The output is the difference between the automatic operation signal V _A and the manual operation signal V _H , that is, (V _A −V _H ). Also,
The output of the second differential amplifier OA ₂ is (V _A - V _H )
The capacitor C also stores this (V _A -V _H ) at the same time. On the other hand, the output of the third differential amplifier OA ₃ is the difference between the automatic operation signal V _A and the voltage (V _A - V _H ) stored in the capacitor C,
V _A −(V _A −V _H )=V _H. Therefore, the +input and -input of the fourth differential amplifier _OA4 are each _VH , and are equal to each other, the fourth differential amplifier _OA4
The output becomes zero and is stable.

Next, when switching from "manual operation" to "automatic operation", the switches SW ₁ and SW ₂ are set to "open", and the automatic/manual changeover switches SW ₃ to _{SW 5} are set to the automatic side A. At this moment of switching, the output of the fourth differential amplifier _OA4 is zero, so the polarity discrimination circuit
From PD, UP signal UP and down signal DOWN
Also, since the voltage V is zero from the voltage/frequency converter V/F, no clock pulse is sent out, so the operating unit OP retains the value immediately before switching in "manual mode". Also, since the switches SW ₁ and SW ₂ are open, the (10) input of the second differential amplifier OA ₂ is zero through the resistor R ₁ , and the (-) input is connected to the capacitor C.
The output of the second differential amplifier OA ₂ is near the power supply voltage of the second differential amplifier OA ₂ with _the opposite polarity of ( _{V A -} V _H ). It is fixed at the saturation voltage V _C. As a result, the storage voltage (V _A -V _H ) of the capacitor C is V _C /R ₂ A/sec, where A in A/sec indicates the unit of ampere.

After a time T (sec) expressed by (V _A - V _H )=V _C /R ₂ C·T, the storage voltage of the capacitor C becomes zero, and the capacitor C stops stably. This embodiment is shown in Figure 2a. In Figure 2 a, A is manual →
It shows the automatic switching point, B shows the area during manual operation, and C shows the area of automatic operation.

When the hold capacitor C is automatically adjusted, it is pulled by the output (saturated output) of the second differential amplifier OA _{2 and} discharged, so the amount of discharge is large and is faster and more stable than when discharging simply through a resistor. reach the state.

As a result, the output of the third differential amplifier OA ₃ is V _H
After a time T (see FIG. 2a), it becomes V _A , and thereafter outputs V _A , that is, an automatic operation signal. Then, the fourth differential amplifier OA ₄ receives the automatic operation signal V _A
Outputs the difference between the manual operation signal (opening signal) V _H and
Polarity discrimination circuit PD that discriminates whether the output is positive or negative
The voltage/frequency converter V/F sends an up signal UP or a down signal DOWN and a clock signal CLOCK proportional to the difference between the automatic operation signal V _A and the manual operation signal V _H to the reversible counter CNT, and performs the required counting. After that, the output is converted to an analog signal by the D/A converter D/A, and the output is converted to air pressure by the voltage/air pressure converter V/P to drive the operating part OP. Move the operation signal (opening signal) _VH .

and the fourth differential amplifier OA ₄ at the point V _A =V _H
The output becomes zero, stopping the up signal UP and down signal DOWN and the clock CLOCK from the voltage/frequency converter V/F, and turning on the automatic operation signal V.
The operation unit OP is controlled by _A.

In the manner described above, the change from "manual" to "automatic" is bumpless.

The means for outputting the manipulated variable is configured to provide a clock signal that regulates the time (speed) required for the operating section to equilibrate in response to the magnitude of the difference signal from the output means during automatic adjustment. It is configured.

Also, after switching from “manual” to “automatic”,
If the automatic operation signal V _A fluctuates as shown in Figure 2 b until the operating part OP finally matches the automatic operation signal V _A , that is, within the T section of Figure 2 a, , the operation unit OP operates in response to this variation. In addition, in Figure 2b, A, B,
C corresponds to A, B, and C in Figure 2a.

FIG. 3 is a block diagram showing another embodiment of the invention. In FIG. 3, the same parts as in FIG. 1 are given the same reference numerals, and their explanation will be omitted. The difference from Fig. 1 is that a voltage/current converter V/I is used instead of the voltage/air pressure converter V/P, and a feedback signal corresponding to the manipulated variable is sent to the output side of the D/A converter D/A. The reason is that I tried to take it out from there.

FIG. 4 is an explanatory diagram of the operation of FIG. 3. After switching from "manual" to "automatic", the automatic operation signal is kept within section T until the operating part OP finally matches the automatic operation signal V _A. When V _A fluctuates, the manual operation signal V _H changes as shown in the figure, and the operating section OP operates in accordance with this fluctuation. Note that in FIG. 4, A, B, and C correspond to A, B, and C in FIG. 2A, respectively.

Fig. 5 is a block diagram showing another embodiment of the embodiment shown in Figs. 1 and 3, surrounded by chain lines, and shows a case where only one switch is opened/closed when switching from manual to automatic mode. It shows. In Fig. 5, the same numbers as in Figs. 1 and 3 indicate corresponding parts, and the hold capacitor C is the second and third capacitor.
The variable point of the variable resistor VR connected to the (-) input terminals of the differential amplifiers OA ₂ and OA ₃ and inserted between the output terminal of the second differential amplifier OA ₂ and the ground is connected to the variable point of the variable resistor VR through the resistor R. (-) Connected to the input end.

In the circuit configured as described above, during manual adjustment, the difference signal between the output signal of the controller, that is, the automatic operation signal V _A , and the feedback signal corresponding to the operation amount, that is, the manual operation signal V _H , is held in the capacitor C. During automatic adjustment, capacitor C is discharged by a fixed amount, and when it is completely discharged, it remains in that state, and the automatic operation signal V _A and capacitor C
The operation of outputting a signal related to the operation obtained by subtracting (subtracted) the manual operation signal V _H from the voltage difference between the terminal voltage and the terminal voltage is the same as in Figs. The explanation will be omitted.

As is clear from the above explanation, according to the present invention, even if there is a difference between the operational output for manual operation and the operational output for automatic operation, switching from manual to automatic can be performed bumplessly. Switching from to manual is bumpless, and switching between manual and automatic operation can be bumpless and balanceless in both directions, and mutual switching between automatic output from the controller and manual output from the manual operation section is bumpless.・Since it can be performed without balance, the practical effect is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of an automatic/manual switching device for a controller according to the present invention, FIG. 2 is an explanatory diagram of the operation of FIG. 1, and FIG. 3 is a block diagram showing another embodiment of the present invention. FIG. 4 is an explanatory diagram of the operation of FIG. 3, and FIG. 5 is a configuration diagram extracting and showing another embodiment of the main part of the embodiment shown in FIGS. 1 and 3. OA ₁ to _{OA 4} ... Differential amplifier, MO ... Manual operation section, SW ₁ , SW ₂ ... Switch, SW ₃ , SW ₅ ... Automatic/manual changeover switch, OP ... Operation section, C ......
capacitor.

Claims (1)

[Claims] 1. Amplify and output the difference input between the output signal of a regulator that produces an output obtained by performing a desired calculation on the deviation between the measured value from the process and the set value, and the feedback signal corresponding to the manipulated variable. and an input from the output of the first differential amplifier through a switch that is closed during manual adjustment as the first input, and an input from the output as the second input. a second differential amplifier that amplifies and outputs the difference, a hold circuit that holds the output of the first differential amplifier in a capacitor during the manual adjustment, and a difference between the output of the controller and the output of the hold circuit. a third differential amplifier that amplifies and outputs an input; a fourth differential amplifier that amplifies and outputs a difference input between the output of the third differential amplifier and the feedback signal;
a manual operation section that outputs a manual switching signal and a manual operation signal including an up signal and a down signal; and a manual operation signal that includes a signal from the fourth differential amplifier and an up signal and a down signal from the manual operation section. means for receiving and transmitting the manipulated variable to drive the operating end via an automatic/manual changeover switch, and a means for transmitting the manipulated variable for driving the operating end through an automatic/manual changeover switch, and a means for transmitting the charge of the capacitor of the hold circuit during automatic adjustment through a resistor connected to the output of the second differential amplifier. and a means for maintaining the charge in the capacitor in a zero state by discharging it in a fixed amount at a time, so that the switching signal between manual operation and automatic operation can be made bumpless and balanceless in both directions. Automatic/manual switching device for controllers. 2 The means for receiving the signal from the fourth differential amplifier and the manual operation signal including the UP signal and the DOWN signal from the manual operation unit via the automatic/manual changeover switch and transmitting the operation amount for driving the operation end is the operation unit. a clock generation circuit that generates a clock signal that regulates the time required for the automatic/manual changeover switch to reach equilibrium; a reversible counter that counts the input clock signal from the clock generation circuit; a D/A converter that converts the digital signal from the reversible counter into an analog signal; The automatic/manual switching device according to claim 1, further comprising a converter for converting into current.