JPS5977502A - Automatic/manual switching circuit - Google Patents

Abstract

PURPOSE:To execute balancelessly and bumplessly automatic/manual switching in both directions by using an automatic input signal as an automatic operating output at the time of an automatic operation, and making an output signal of an amplifier follow a value of a manual operating output at the time of a manual operation. CONSTITUTION:By an operation of automatic/manual changeover switches SW1-SW3, a negative feedback amplifier of a gain 1 is formed by an amplifier 1 and a feedback circuit 2 at the time of an automatic operation, and an automatic input signal is used as an automatic operating output through the negative feedback amplifier and a holding amplifier 3. On the contrary, at the time of a manual operation, as an input of the amplifier 3, an automatic operating output value (holding outut value) immediately before switching is made a reference, and from this value, an increase and decrease signal is added as a manual operating signal and is used as a manual operating output, and also an output signal of a negative feedback circuit which inputs a difference signal between an output of the amplifier 1 which inputs the automatic input signal, and the manual operating output is used as a negative feedback signal, so that an output signal of the amplifier 1 follows a value of the manual operating output.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is an automatic/
The present invention relates to an automatic/manual switching circuit that can switch from manual switching to dual-directional valve balanceless/bumpless switching.

[Prior art]

In automatic process control devices, automatic operation is normally performed, but manual operation is performed to ensure safety when starting and stopping a process.

What is important here is that when switching from manual to automatic or 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, conventionally, an automatic/manual switching circuit as shown in FIG. 1 has been used. In Fig. 1, SW is a changeover switch, V-to-manual operation signal, P
S is a push button switch, and 13M is a balance meter. For example, if the changeover switch SW is switched to the A'' side, the automatic input signal V+ becomes the operation output V0 and automatic operation is performed.In this state, to switch to manual operation, first press the 1st push button Ps. Press to automatically input signal V
Connect balance meter 13M between + and manual operation signal 7m. As a result, the balance meter BM indicates the difference voltage between the automatic input signal V and the manual operation signal v7, so the manual operation signal is adjusted so that the indication from the balance meter BM becomes zero. By this balance operation, the automatic input signal V+
Since it is possible to match the values of the manual operation signal V and the value of the manual operation signal V, if the selector switch SW is then set to M'', the operation output ■
. ■ Manual operation signal to bumpless. K can be switched and manual operation can be changed to 8-j. Further, switching from manual operation to self-fIh operation can be similarly performed bumplessly by performing the operation opposite to the above. However, the conventional automatic/manual switching circuit shown in FIG. 1 requires a balancing operation in both directions, which is disadvantageous in that it is extremely troublesome for the operator.

[Purpose of the invention]

The purpose of the present invention is to eliminate the need for balance operation during switching (hereinafter referred to as balanceless) and to enable smooth switching without causing sudden changes in the operation f1 output.
C-, which provides a manual switching circuit. Another object of the present invention is to provide an automatic/manual switching circuit capable of performing balanceless/bumpless automatic/manual switching in both directions.

[Summary of the invention]

The present invention is provided with a plurality of moving automatic/manual changeover switches, an amplifier, a feedback circuit of the amplifier, and a hold amplifier (holding amplifier), and when the changeover switch is operated, the amplifier and the feedback circuit forming a negative feedback amplifier with a gain of 1, and outputting the automatic input signal via the negative feedback amplifier and the hold amplifier,
Conversely, in the manual mode, the automatic operation output value (hold output value) immediately before switching is input to the hold amplifier.
Using this value as a reference, an increase/decrease signal from this value is added as a manual operation signal to obtain a manual operation output, and the feedback input is a difference signal between the output of the amplifier that receives the automatic input signal as an input and the manual operation output. The output signal of the circuit is used as a negative feedback signal of the amplifier, and the output signal of the amplifier is configured to follow the value of the manual operation output.

[Embodiments of the invention]

Below, the automatic/manual switching circuit according to the present invention will be explained in the second section.
This will be explained in detail using the principle configuration diagram shown in the figure. In Figure 2, 1 is an amplifier for gain, 2 is a feedback circuit with gain B,
3 is a hold amplifier which sends out analog output V0 corresponding to the analog input from input terminal 31;
■ Hold output of a certain value for the input signal from.

Based on the value of , output from that value only while the signal is being input. It operates in such a way that it increases or decreases. 4 is a manual operation signal generation circuit, which is composed of an increase/decrease switch, an increase/decrease signal source, and an integrator (not shown), and is a circuit that generates a ramp signal that gradually increases or decreases from zero by operating the increase/decrease switch. be. Further, SW1 to SW3 are interlocked with each other to automatically/manually turn off (in case of emergency switch A'', the mode is set to manual mode. Ci is a capacitor, and a is a resistor.

First, let's talk about the case where the changeover switches SWI to SW3 are connected to the automatic mode on the LI Atp side as shown by the dotted lines. 31 and the output signal of the feedback circuit 2 via the resistor R and the changeover switch 5Vv2.
I) Curved n'';'A'1 Input to circuit 2.

Here, if the gain B of the feedback circuit 2 is B>1, then V+2■
, becomes. Furthermore, a difference (V+Vr) is taken between the output signal Vt of the feedback circuit 2 and the automatic input signal 'V+, and the result is input to the amplifier 1.

Here, if the gain of amplifier 1 is AΣ1, then Vt = V as described above, so V, = V+.

Of course, the amplifier 1, the feedback circuit 2, and the resistor R1 constitute a negative feedback amplifier with a gain of l. Therefore, the automatic operation output of hold amplifier 3■. has a value equal to the automatic input signal VI.

Next, a case will be described in which the switches SW1 to SW are switched to the manual mode on the ttMtt side. switch SW
3, a manual operation signal generation circuit is connected to the input of the input terminal 32 of the hold amplifier 3.

When the switch is changed from ++Ajp to MPI, hold amplifier 3 holds the output V, (=V+) of amplifier 1 immediately before switching, so the output of hold amplifier 3 ■. is also automatically operated immediately before switching. Output V. (=V
+) holds a value equal to In other words, it is possible to switch from automatic to manual to balanceless/bumpless. Thereafter, by operating the increase/decrease switch of the manual operation signal generation circuit 4, an increase or decrease ramp input is applied to the input terminal 32 of the hold amplifier 3, increasing or decreasing based on the automatic operation output value immediately before switching. A manual operation output v0 can be obtained. −・force, this manual operation output V
, and the output signal V of the amplifier 1 via the switch SW2. Here, in order to distinguish it from the value when outputting automatic operation, for convenience, the value when outputting manual operation is v, , (
=vn), the difference signal (V, -V,) is input to two feedback circuits. Once, the output signal V of the feedback circuit 2
t is Vr=B (V-V-)...(1)
becomes. A difference (Vi Vt) is taken between this feedback signal Vt and the automatic input signal V+, and the result is input to the amplifier 1. Therefore, the output V of the amplifier 1 is given by equation (2).

V, = A (Vi-Vf) (2) (IJ,
(From the 2J formula, V-=A CVi B (V---V,
(3), V- (V'++ BV-)/ (1/A + B) Here, if the gain A of amplifier 1 is A>1 and - deviation, V, =
(Vi/B) +V m −・−・・
(C is expressed as 4.) Here, the automatic input signal ■
Even if 1 is taken as 100%, if the utilization B of the feedback circuit is taken as 100, then the ratio on the right side of equation (4) is 1 term 1d, V + / B =
100%/100=1%, H= 1000
Since HV+/B=100%/1000=0.1%, it can be ignored. In other words, equation (4) can be expressed as equation (51).

■, 1- (5) Therefore, the output ■1 of the amplifier 1 always follows a value equal to the manual operation output V.

Here, turn the changeover switches SWI to SW3 again to ttM'''
If you change it to the A” side and switch to automatic mode, at that moment the capacitor C connected to switch SW2
Since the value of the manual operation output ■1 has been charged in the amplifier 1, the value of the output signal V of the amplifier 1 is equal to the value of the manual operation output ■1 immediately before switching, as shown in equation (5). Therefore, there is no change in the operation output of the hold amplifier 3, and it is possible to switch to balanceless/bumpless operation. after that,
When the charging voltage of the capacitor C and the resistance value of the resistor R exceed the capacitance of the capacitor C and the resistance value of the resistor R, the charging voltage of the capacitor C is discharged at a constant rate.
The output of the hold amplifier 3 is also the automatic operation signal ■ which is equal to the value of the automatic input signal ■1. becomes.

In this way, switching from automatic to manual and from manual viewing 1 to automatic can be done without balance/bumpless in both directions [7
I can change.

FIG. 3 is a diagram showing a specific embodiment of the automatic/manual switching circuit according to the present invention. In FIG. 3, the same parts as in FIG. 2 are represented by the same symbols. In the embodiment shown in FIG. 3, the amplifier shown in principle configuration I-1 in FIG. Same as Figure 2. The same applies to Moe's first work, so its explanation will be omitted.

Note that this is not limited to the groove of the dispersive circuit 2 or the embodiment shown in FIG. 2; for example, as shown in FIG.
If the configuration is such that the value of the manual operation output V, n when W3 is "M" is charged across the capacitor C, it is also possible to omit the amplifier (JJ' 2).

In addition, in FIG. 2, the manual operation signal generation circuit 4 is configured to generate a ramp input using an increase/decrease switch, a -1 pressure source, and an integrator, but the hold amplifier 3
Depending on the configuration of the input circuit of the input stream 1 child 32, the same effect can be obtained even if the pulse train signal is generated by operating the increase/decrease switch.

〔Effect of the invention〕

As described above, according to the present invention, automatic and manual switching can be performed in both directions without bumping.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a conventional automatic/manual switching circuit, and FIG. 2 is a diagram showing the principle configuration of the automatic/manual switching circuit according to the present invention.
FIGS. 3 and 4 are diagrams showing specific embodiments of the present invention.

Claims (1)

[Claims] 1. It is equipped with a plurality of moving automatic/manual changeover switches, an amplifier and feedback circuit, a hold amplifier, and a manual operation signal generation circuit, and when the changeover switch is operated, the amplifier and the feedback circuit are switched. a negative feedback amplifier that sends out an output proportional to the automatic input signal, and configured to send out an automatic operation output proportional to the automatic input signal as the output of the hold amplifier that receives the output of the amplifier as an input, At the time of manual switching, by adding the manual operation signal of the manual operation signal generation circuit as the input of the hold amplifier, the output of the hold amplifier is increased or decreased using the 1/1 operation output (hold output value) immediately before switching as a reference value. The feedback circuit is configured to obtain a manual operation output, and the output signal of the feedback circuit that receives the difference signal between the output of the amplifier that receives the automatic input signal as input and the manual operation output is used as a negative feedback signal of the amplifier, and The output signal of the amplifier is configured to follow the value of the manual operation output! Easy automatic/manual switching circuit.