JPS5833561B2 - Manual reset type controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Generally, when a controller switches between automatic operation and manual operation, a sudden change in its output adversely affects the control process.

For this reason, it has conventionally been required for controllers to perform a balanced operation so that the output does not suddenly change when switching between automatic operation and manual operation.

However, balancing both operation outputs requires the operator to perform a complicated balancing operation, or requires a special balancing operation device.

Furthermore, even if controllers have the same external shape, if there are fundamental differences in operation, there is a risk that the operator will feel reluctant to operate the controllers and may make erroneous operations.

This invention has a control system that has a hold circuit that manually creates a manipulated output and electrically holds it, and a manual reset that allows a set value to be manually given, and that performs automatic control according to a deviation signal. To provide a controller which does not require a balancing operation when switching between systems and which prevents sudden changes in output.

First, in order to facilitate understanding of the present invention, a conventional device for switching between a manual control device and a manual reset type controller will be explained with reference to FIG.

Process input signal VPV from signal source 1 is input to operational amplifier 2
is supplied to the non-inverting input terminal of

The reference signal VSP from the power supply 4 is applied to the inverting input terminal of the operational amplifier 2 through the variable resistor 5, and the deviation signal VPV vsp is obtained at the output side of the operational amplifier 2.

A feedback current IA isolated from the amplifier circuit through the feedback circuit of the operational amplifier 2 and a manual reset current IM in the opposite direction.
R is applied to the inverting input of amplifier 2.

A feedback current flows through the resistor 6 with the resistance value RF, and the voltage vA
A manual reset current IMR flows through a resistor 7 having a resistance value RMR, and a voltage VMR is generated.

The output of this operational amplifier 2, that is, the output of automatic adjustment operation ■A
When you calculate.

However, A1 is the gain of the operational amplifier 2, and 1/KP is the division ratio of the variable resistor 5.

In this way, the automatic output vA is the deviation manual power vpv-VSF
with an output proportional to.

It is given as the sum of the manual reset output VMR.

Furthermore, a manual operation section 10 is provided.

This is designed to electronically hold the manual operation output, and a holding capacitor 12 is connected between the input and output terminals of the operational amplifier 11, and the signal from the manual control means 13 is transmitted to the inverting input terminal of the operational amplifier 11. An output vM corresponding to this is obtained at the output side of the amplifier 11, and a corresponding charge is charged to the capacitor 12, and its value is held.

A drift compensation path 14 is connected in parallel with the capacitor 12 to control the output so that it does not deviate by more than a predetermined value from its manually operated position.

The manual operation output vM and the automatic operation output ■A are switched by a changeover switch 16 and provided to the control system.

In this way, whether automatic operation and manual operation can be switched as necessary, or whether automatic output ■
A and 1 manual output vM are respectively indicated by the pointers of the twin needle type indicator, and the manual control means 13 is operated so that they match.
, and the changeover switch 16 is switched in a state where they match.

By performing such a balancing operation, the operation output is prevented from changing suddenly during switching.

It is troublesome to carry out balancing operations each time the switch is made in this way.

Note that automatic reset type controllers, rather than manual reset, operate automatically to prevent sudden changes in output when switching between manual operation and manual operation.

For this reason, when looking at the front panel board of a similar controller, the operator cannot tell whether it is an automatic reset type or a manual reset type, and during manual operation, the operator cannot tell whether the controller is an automatic reset type or a manual reset type. If the output does not follow the manual output, switching from manual to automatic will result in incorrect operation.

As described above, this invention uses a circuit that electronically holds the operating value during manual operation, and also eliminates sudden changes in output without performing a balancing operation when switching with automatic operating means having manual reset. The present invention provides a manual reset type controller that does not change.

In this invention, a manual operation signal is guided to the input side of an operational amplifier connected to a capacitor that holds this operation output value during manual operation, and another impedance is added to this operational amplifier during automatic operation, and a manual reset signal is supplied. and the signal associated with the deviation input signal, so that the sum of the signals associated with the deviation input signal is obtained at the output of the operational amplifier.

FIG. 2 shows the configuration of the first embodiment of this invention.
The analog time keeping circuit 10 during manual operation is an operational amplifier 11. The structure of the capacitor 12, manual operation means 13, and drift compensation circuit 14 is the same as the corresponding part in FIG.

In this embodiment, one end of a switch 23 as a second switch means that is turned off during manual operation is connected to the inverting input terminal of the operational amplifier 11, and a resistor 18 is connected to the output terminal of the operational amplifier 11 and the switch 23 is connected to the inverting input terminal of the operational amplifier 11. Connected between other terminals.

Also during automatic operation. In order to cut off manual operation input, a switch 24 as a first switch means is provided between the connection point of the manual setting control means 13 and the drift prevention circuit 14 and the connection point of the capacitor 12 and the inverting input terminal of the amplifier 11. is connected.

This switch 24 is turned on during manual operation.

In order to supply a deviation input, a set value VSP is inputted from a terminal 30 through a resistor 31 to the non-inverting input terminal of the operational amplifier 32, and a process signal VPV is applied to a terminal 33, which is connected to the inverting input terminal of the operational amplifier 32 through a resistor 34. entered at the end.

This non-inverting input terminal is connected to a reference potential point through a resistor 35.

The output side of the operational amplifier 32 is connected to a reference potential point through a variable resistor 36, and the movable element of the variable resistor 36 is connected to an inverting input terminal through a feedback resistor 37.

In this way, the output side of the amplifier 32 receives a deviation signal, that is, V
A signal proportional to PV vsp is obtained, the output of which is applied via resistor 40 to the inverting input terminal of operational amplifier 41.

A non-inverting input terminal of this operational amplifier 41 is connected to a reference potential point.

A resistor 43 is connected between the inverting input terminal and the output terminal of the operational amplifier 41.

On the other hand, manual reset signal source 26 is connected to the inverting input terminal of operational amplifier 41 via resistor 42 .

The output terminal of the operational amplifier 41 is connected to the resistor 20 and the capacitor 2.
Switch 23 and resistor 18 through two parallel connected circuits.
It is connected to the connection point 25 with.

That is, in the present invention, the sum of the deviation signal and the manual reset signal is obtained on the output side of the analog hold circuit 10 during automatic control, and the addition is performed before the signal is supplied to the analog hold circuit 10. This is done in advance.

As already explained, in FIG. 2, the output of the operational amplifier 32 is supplied through the resistor 40 to the inverting input terminal of the operational amplifier 41, and the output of the manual reset setting circuit 26 is supplied to this input terminal through the resistor 42. ing.

Further, a resistor 43 is connected between the inverting input terminal of the operational amplifier 41 and its output terminal, and the non-inverting input terminal of the amplifier 41 is connected to a reference potential point.

Also, in this configuration, the resistors 40, 42 and 43 are selected to have the same resistance value.

In this way, the deviation signal from the operational amplifier 32 and the manual reset signal from the 1 manual reset signal circuit 26 are added, and the added signal is supplied to the connection point 25 through the parallel circuit of the resistor 20 and the capacitor 22.

In this case, the polarity of the signal is inverted by the amplifier 41, but the signal supplied to the amplifier 32 is previously inverted, that is, the process signal VPV is supplied to its non-inverting input, and the reference voltage VSP is supplied to its inverting input. What is necessary is to control the changeover switch provided at the front stage of the amplifier 32 in this manner.

In this invention, as shown in the embodiment of FIG.
3 is on and switches 24 and 38 are off, that is, in the automatic operation state, the capacitor 12 is connected between the input and output of the operational amplifier 11, so this output ■.

is held charged in the capacitor 12.

Therefore, when switching from this state to manual operation, that is, when switch 23 is turned off and switches 24 and 38 are turned on, the output is V due to the presence of capacitor 12.

is maintained. Thereafter, the output ■ is controlled by the manual operating means 13.

can change.

Therefore, the output ■. Equilibrium switching takes place without sudden changes in .

In this way, the output V during automatic operation.

By providing the circuit 10 that maintains the output V even when switching from automatic operation to manual operation.

does not change suddenly.

Due to the presence of the capacitor 12 in the holding circuit 10, during automatic operation, that is, when the switch 23 is on and the switches 24.38 are off, if the capacitor 22 is not provided, even if the control signal suddenly changes, the capacitor 12 A delay occurs due to the first-order delay characteristic determined by the time constant of the resistor 18.

Capacitor 22 is necessary if this delay is to be avoided.

That is, in this case, the response to the input is transiently performed through the capacitor 22.

Therefore, the capacitance of capacitors 12 and 22 is CM.

The resistance values of CM resistors 18 and 20 are each R4°RM.
By setting the relationship CMRM=CHR4 between them, you can obtain a controller that operates without delay in response to sudden changes in the control signal during automatic operation, and also allows you to switch from automatic control state to manual operation state. It becomes possible to perform the switching without a balancing operation.

However, if response delay is not a particular problem. resistance 20
It is possible to have a configuration in which the capacitor 22 connected in parallel with the 22 is removed.

Further, in this embodiment, even when switching from manual operation to automatic control state, the switching is performed without performing a balancing operation and the output does not suddenly change.

That is, in manual control, one connection point 25 is connected to the reference potential point through the switch 38, and therefore the connection point 25 side of the capacitor 22 serves as the reference potential point.

The capacitor 22 is charged with the output of the sum of the output of the manual reset circuit 26 and a signal proportional to the deviation signal.

Moreover, since the non-inverting input terminal of the operational amplifier 11 is connected to the reference potential point, the operational amplifier 11 operates so that its inverting input terminal becomes equal to the reference potential point.

Therefore, when switching from manual operation state to automatic operation state,
Even if the reference potential point of the connection point 25 is connected to the inverting input terminal of the amplifier 11 through the switch 23, no potential fluctuation occurs therebetween.

Therefore, switching is performed without sudden changes in the output.

However, after the switching, the output level of the manual output changes slowly to the steady state output level of the automatic control with a temporary delay characteristic of the time constant CHR4.

In this way, even if the manual operation using the analog holding circuit 10 and the automatic control with manual reset are switched without performing any particular balancing operation, the output will not suddenly change.

It is easy to understand that by doing this, automatic and manual switching can be performed without performing a balancing operation and without sudden changes in output.

The other impedance circuit in this Figure 2 is resistor 1
8.20 and capacitor 22.

In FIG. 3, the same parts as in FIG. 2 are denoted by the same reference numerals to indicate the configuration thereof. This embodiment is a resistor in the circuit shown in FIG. 2. Vessel 1
8 and 20 are omitted, and the output of the amplifier 41 is connected to the connection point 25 through the capacitor 45 as shown in FIG.
At the same time, the output terminal of this amplifier 41 is connected to the inverting input terminal of an amplifier 47 through an inverting amplifier 46.

Also, the output of the analog hold circuit 10 is supplied to the non-inverting input terminal of the amplifier 47, and the output terminal of the amplifier 4T is connected to the resistor 4.
8 to connection point 25.

In this case, the capacitance of capacitor 45 is selected to be equal to that of capacitor 12.

In this way, a signal corresponding to the sum of the deviation signal and the manual reset signal is supplied to the operational amplifier 11, and the amplifiers 46 and 47 and the resistor 48 act as a follow-up circuit.

In this case as well, the output V upon switching from the automatic control state to the manual control state or vice versa.

The principle that prevents sudden changes in is the same as in the case of Fig. 2.

However, after switching from manual control state to automatic control state,
The method of making the output ■o equal to the sum of the value related to the deviation input and the manual reset value differs from that in FIG.

That is, in the case of FIG. 2, the output level changes to the steady state output level in automatic control via the resistors 20 and 18 with the first-order lag characteristic of the time constant CHR4, but in the case of FIG.
, 47 and resistor 48.

The time constant is the product of the resistance value of the resistor 48 and CH.

The other impedance in this case is capacitor 45
, resistor 48, and amplifiers 46 and 47.

FIG. 4 shows a third embodiment of the present invention in which automatic reset is also possible in FIG.

That is, the output side of the manual reset setting circuit 26 and the resistor 42
A switch 51 for connecting and disconnecting the manual reset setting circuit 26 is inserted between the two.

Further, when the connection point 25 is a manual reset, it is connected to the resistor 48 side by a switch 52, and when it is an automatic reset, it is connected to the output side of the amplifier 41 through a resistor 53.

When the switch 51 is turned off and the switch 52 is set to the resistor 53 side, the amplifier 41. This is a circuit to which an arithmetic circuit consisting of resistors 40 and 43 is added.

It is easy to understand that the switching between manual operation and manual operation in this case is performed without performing a balancing operation and without sudden changes in output.

Also, to switch between manual reset and automatic reset,
If the switching is performed through the manual operation state, the switching can be performed without performing one manual balancing operation and without causing a sudden change in the output.

For this purpose, for example, a manual operation switch may be provided in the operating path of a changeover switch between manual reset and automatic reset, and the switch may be configured mechanically or electrically so that it is always in the manual operation state.

As explained in detail above, according to the present invention, in any of the embodiments, the output is held in an analog manner during manual operation, and by adding or adding another impedance circuit during automatic control, the analog hold circuit is Since the sum of the manual reset signal and the signal related to the deviation signal is obtained on the output side, it is possible to switch between manual operation and automatic operation without performing a balancing operation and without sudden changes in the output. It is.

In each embodiment, the deviation signal may be a zero differential value, or the difference between the differentiated process signal and the reference signal may be used.

[Brief explanation of drawings]

FIG. 1 is a principle diagram showing a conventional manual reset type controller, and FIGS. 2 to 4 are circuit diagrams showing the configurations of first to third embodiments of the manual reset type controller according to the present invention. 10: Analog hold circuit, 11: Operational amplifier, 12
: Capacitor, 13: Manual operation circuit. 26: Manual reset setting circuit, 30: Process signal supply input terminal.

Claims (1)

[Scope of Claims] 1: an analog hold circuit comprising an operational amplifier with a capacitor connected to a feedback circuit; manual setting means for guiding a manual operation signal to the input of the operational amplifier via a first switch means during manual operation; a second switch means having one end connected to the input end of the operational amplifier; a feedback means comprising a resistor connected between the other end of the second switch means and the output end of the operational amplifier; and the feedback means and a third switch connected between the connection point of the second switch means and the common potential point.
a switching means; an adding means comprising a resistor and an operational amplifier for adding the manual reset signal from the manual reset signal supply means and the signal related to the deviation input from the deviation input supply means; The output signal of the addition means is applied to the connection point via a resistor, and during manual adjustment, the first switch means and the third switch means are turned on, and the second switch means is turned off, so that the manual operation output is converted to the analog signal. obtained at the output end of the hold circuit,
At the time of automatic adjustment, the first switch means and the third switch means are turned off, and the second switch means is turned on, so that the automatic operation output of the sum of the signal related to the deviation input and the manual reset signal is held in the analogue state. A manual reset type controller characterized in that the controller is configured so as to be reset at the output end of the circuit. 2. An analog hold circuit consisting of an operational amplifier with a capacitor connected to a feedback circuit; 1. Manual setting means for guiding a manual operation signal to the human power of the operational amplifier via a first switch means during manual operation; and 1. an input terminal of the operational amplifier. a second switch means with one end connected to the second switch; a feedback means with the other end of the second switch connected with a resistor and an operational amplifier whose non-inverting input terminal is supplied with the output of the operational amplifier; A third switch means connected between the connection point with the second switch means and a common potential point and a signal related to the manual reset signal from the manual reset signal supply means and the deviation input from the deviation input supply means. Adding means comprising an adding resistor and an operational amplifier; the output terminal of this adding means is connected to the inverting input terminal of the operational amplifier in the feedback means through an inverting amplifier, and the output signal of the adding means is connected to the connection point. The first switch means and the third switch means are turned on during manual adjustment, and the second switch means is turned off to provide a manual operation output to the output terminal of the analog hold circuit during automatic adjustment. The first switch means and the third switch means are turned off, and the second switch means is turned on to output an automatic operation output of the sum of the signal related to the deviation input and the manual reset signal to the output of the analog hold circuit. A manual reset type controller characterized in that it is configured to be set at the end.