JPS59212901A - Automatic/manual switching circuit - Google Patents

Abstract

PURPOSE:To perform the automatic/manual switching operation in a balanceless and bumpless way by making use of the time constant of a parallel circuit consisting of a capacitor and a resistance. CONSTITUTION:In a manual operation output mode the difference voltage between an automatic input signal (ei) and a manual operation signal (em) is charged to a capacitor C of a parallel circuit consisting of said capacitor C and a resistance R to have a waiting mode. An operational amplifier 1 is added to use the signal (ei) as an input only in an automatic mode, and therefore the amplifier 1 is connected to said parallel cirlcuit in the form of a feedback circuit of the amplifier 1. The charging voltage of the capacitor C is utilized at an instant when a manual mode is switched to an automatic mode, and hereafter the difference voltage is discharged with the time constant decided by the value of the C and the R respectively. In such a way, the automatic/manual switching operation is possible in a balanceless and bumpless way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an automatic/manual switching circuit that is suitable for application to a manual operating device and is capable of switching the automatic/manual switching to a balanced and bumpless switch in both directions. [Background of the Invention] In a gross control device, automatic operation is normally performed, but manual operation is performed to ensure safety when starting and stopping a process. In such cases, a manual operator having an automatic/manual switching function is used. What is important here is that when switching from manual to automatic and from automatic to manual, it is necessary to switch smoothly without sudden changes in the operating output (hereinafter referred to as bumpless switching).

For this reason, an automatic/manual switching circuit shown in FIG. 1 has conventionally been used as a manual operation device.

In FIG. 1, SW is a changeover switch, e- is a manual operation signal, PS is a push button switch, and BM is a balance meter.

In FIG. 1, for example, the switching 2-inch SW is VI
If it is on the A" side, the automatic input signal el is the changeover switch SW.
The output signal directly becomes the automatic operation output signal e0 through the output signal e0, and automatic operation is performed. To switch to manual operation in this state,
First, the pushbutton switch PS is pressed to instruct the balance meter BM to indicate the difference signal between the automatic input signal el and the manual operation signal e□, and the manual operation signals are adjusted so that the deviation becomes zero.

This balanced J・■ product has an automatic input signal e and a manual operation signal e. , and then turn the selector switch SW.
By switching to //, the operation output e6 is bumplessly switched to the manual operation signal e□, and manual operation can be performed thereafter.

In the conventional automatic/manual switching circuit shown in Fig. 1,
If the automatic input el is the manual output of the PID controller,
Bumpless switching from manual operation to automatic operation is also possible by performing the reverse operation as described above, but since it is essentially impossible to change the value of the automatic signal manually, it is not possible to switch from manual to automatic operation. Press switching is not possible. Further, even when switching, a balancing operation is required as described above, which is very troublesome for the operator in case of reeds or emergencies.

For this reason, conventional automatic/manual switching requires no balance operation in both directions (hereinafter referred to as "balanceless").
In addition, there was a need for a manual operating device that can perform bumpless switching without causing sudden changes in operating output.

In addition, in PID controllers that have proportional, integral, and differential elements, controllers that can switch automatic/manual switching in both directions balanceless and bumpless by using integral elements have been put into practical use. However, intervening an integral element in the automatic input signal would override the function of a manual operating device and cannot be put to practical use.

[Purpose of the invention]

The purpose of the present invention is to convert automatic to manual operation suitable for manual operating devices.
Another object of the present invention is to provide an automatic/manual switching circuit capable of switching from manual to automatic in both directions without balance or bumpless. Another object is to realize an automatic/manual switching circuit that can switch from manual to automatic independently and in a balanceless/bumpless manner without intervening an integral element in the automatic input.

[Summary of the invention]

One drawback of the present invention is that when the operation output is manual, the voltage difference between the automatic human input signal and the manual operation signal is charged across the capacitor in the parallel circuit of the capacitor and the resistor to standby.
Automatic humanization only when automatic.

- An operational Ir amplifier with an input of Sina is interposed, and the parallel circuit is connected as a feedback circuit of the operational amplifier Rlj, so that the charging at both ends of the capacitor is carried out at the moment of switching from manual to automatic mode. Using the voltage, 111, which is the same as the manual operation output immediately before automatic switching as the output of the operational amplifier, is sent as operation No. 16, and then the above is performed using the time constant added by the values of the capacitor and resistor of the parallel circuit. The differential voltage charged across the capacitor is discharged, and finally the operational amplifier functions as a simple buffer amplifier, and the automatic input signal is outputted via the buffer amplifier. This makes it possible to switch from manual to automatic without balance or bumpless.

[Embodiments of the invention]

Below, a second embodiment of the automatic/manual switching circuit according to the present invention will be described.
The principle will be explained in detail using the diagram shown in Fig. 2. In Fig. 2, 81-84 are interlocking automatic/manual changeover switches, and when % A //, automatic mode, ' MI
′ indicates manual mode.

In automatic mode A, an automatic input signal el is connected to the positive phase input terminal of the operational amplifier 1, and a parallel circuit consisting of a capacitor C and a resistor is connected between the negative phase input terminal and the output terminal. , the output end is configured to provide an operation output signal, eo. In addition, the operation output signal e0 and the output e1 of the D/A converter 6
are input to the comparator 2, and the output of the comparator 2 is input to the D/A converter 60 via the gate circuit 3 and the UP/DOWN counter 5. When in automatic mode A,
The changeover switches 81 to S4 are configured to be connected in this manner.

When in manual mode M, the UP/DOWN switch is configured with a pushbutton switch or a rebound switch with a neutral point.
The UP/DOWN contact signal from the manual operation circuit 7 is sent to D/Af via the gate circuit 3 and Ul)/DOWN counter 5.
At the same time as being input to the converter 6, the output e of the D/A converter 6,
fl (manual operation signal) is configured to directly become the operation output signal e0.

Further, an automatic input signal el is connected to one end of the parallel circuit of the capacitor C and the resistor, and an operation output signal e is connected to the other end.
0 is connected, and the difference voltage (em-e,) between both signals is charged across the capacitor C. In manual mode M, the changeover switches 81-84 are configured to be connected as described above.

Here, a clock pulse generation circuit 4 is connected to the gate circuit 3, and when the automatic mode is set, the voltage output of the comparator 3 is in the positive direction or the negative direction, and when the manual mode M is set, the clock pulse generating circuit 4 is connected to the clock pulse generating circuit 4. /DOWN The opening/closing of the gate circuit 3 is controlled by the UP/DOWN contact signal of the manual operation circuit 7, and the UP/DOW
N clock pulses are sent from the gate circuit 3 to the UP/DOWN counter 5.

The operation will be explained with reference to FIG. 2 configured in this way.

1) First, when the automatic/manual changeover switches 81 to S4 are in automatic mode 1A, the operational amplifier 1 operates as a simple buffer amplifier with a parallel circuit of capacitor C and resistor as a feedback circuit. The same operation output signal e0 as the automatic input signal el inputted to the device 1 is obtained.

e,=el ・・・・・・・・・・・・
...(1) On the other hand, the operation output signal e, is compared with the D/A converter output e, a by the comparator 2, and the contents of the KUP/DOWN counter 5 are rewritten so that the two are equal, so the D The output e, of the /A converter 6 is always on standby and changes following the trap operation output signal e.

As a result, the automatic mode can also be switched from A to manual mode 'M' without any harassment or bumpless switching.

2) Next, when the automatic/manual WD changeover switches 81 to s4 are in manual mode M, the contents of the UP/DOWN counter 5 are rewritten by manually operating the UP/DOWN hand MJ operation circuit 7. Therefore, the output em of the D/A converter 6, that is, the operation output signal e0 can be changed manually.

(e,=eゎ)-power, and at this time, both ends of the capacitor C are the output e of the A/D converter 6. The differential voltage (em-ei) between the manual operation signal (manual operation signal) and the automatic input signal ei is photoelectronized with the polarity shown and is on standby.

Operation output signal e at the moment when switching from manual mode 1M to automatic mode A. is e, = e, −[
−(e, ei))=e m”””(2), and it is possible to switch to balanceless/bumpless.

From now on, the charging voltage (e, field) across the capacitor C is determined by the time constant T (T=C-
R), and (e--el)= in equation (2).

Finally, the operation output signal e is expressed by equation (1).

It should be noted that the changeover switches 81-82 in FIG. 2 can of course be constructed of mechanical switches, semiconductor switches, or a combination of both. In addition, the changeover switch 83.8
4, the gate circuit 3, and the clock pulse generation circuit 4 are not limited to the example shown in FIG. UP/DOWN when in mode
By the UP/DOWN contact output of manual operation circuit 7, U
The configuration may be such that it can send out a pulse signal that can rewrite the contents of the P/DOWN data 5 in an increasing direction and a decreasing direction.

[Effects of the Invention] As described above, according to the present invention, automatic/manual switching can be made balanceless and bumpless in both directions. i
In addition, it is effective when applied to manual actuators because it can switch from manual to automatic in a balanceless and bumpless manner, and in the automatic state, there is no integral element involved, achieving all the initial objectives. It's large.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a conventional automatic/manual switching circuit, and FIG. 2 is a diagram showing the principle configuration of an automatic/manual switching circuit according to an embodiment of the present invention.

Claims (1)

[Claims] 1. At least a plurality of automatic/manual changeover switches, an operational amplifier and a comparator, a parallel circuit of a capacitor and a resistor, an amplifier down manual operation circuit, an up/down counter,
and a D/A converter, and when the changeover switch is in manual mode, the contents of the counter are rewritten according to the signal from the manual operation circuit as a manual operation output signal via the D/A converter, and The capacitor of the parallel circuit is charged with a voltage difference between the manual operation output signal and the automatic input signal and stands by, and when the changeover switch is set to automatic,
The automatic input signal is connected to the positive phase input terminal of the operational amplifier, and the parallel circuit is connected between the negative phase input terminal and the output terminal, and the output of the output terminal is used as the automatic operation output signal, and
The automatic operation output signal and the output signal of the D/A converter are compared by the comparator, and the contents of the counter are rewritten based on the output of the comparator and sent to the D/A converter. /
The automatic control device is characterized in that the output of the A converter is kept on standby as a value that changes in accordance with the automatic operation output signal, thereby enabling balanceless and bumpless switching between automatic and manual switching in both directions. /Manual switching circuit.