JPS58115502A - Multiple controller - Google Patents

Abstract

PURPOSE:To perform the continuous switching of controlling circuits, by providing a selecting circuit, which selects optimum one of outputs of plural controlling circuits, and a correcting circuit which limits the output range of controlling circuits in accordance with the difference between the output of the selecting circuit and outputs of controlling circuits. CONSTITUTION:A target value set in a target value setter 1 and a feedback quantity of a controlled system 5 are given to controlling circuits 3a-3c through an adder 2. Outputs of circuits 3a-3c are inputted to a selecting circuit 4, and a controlling circuit having a middle value is selected. The output of the circuit 4 is fed back to controlling circuits and is inputted to gain adjusting circuits 6a-6c together with outputs of respective controlling circuits. The difference between the output of the selecting circuit and outputs of controlling circuits is operated in an adder. When this difference is smaller than a prescribed value in a limiter, parameters of controlling circuits are not corrected; but when it is larger than the prescribed value, variable resistances are operated through driving elements to adjust gains of controlling circuits, thus limiting outputs to a certain range.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multiplex control system that constantly repeats correction of other outputs while checking the optimum result among the outputs of a plurality of control circuits.

A conventional device of this type is shown in FIG. The figure shows a feedback control system with eight control circuits (1
) is a target value setter, (2) an adder that adds to the polarity shown in Fi, and (''), (8b), and (ac) are control circuits, and eight units of the same specification are used. (4) is a selection circuit that selects the optimal signal from among the input signals, and (6) is a control target.Furthermore, FIG. 2 shows the internal configuration of the selection circuit (4), and (4a+), (4a2), (4as)
(41)1) , (4Th) , (4b+) , (
4ct).

(402) - (4cs) are all diodes or equivalents.

Next, the operation will be explained. The adder (2) calculates the deviation between the target value set by the target value setter (1) and the control lid fed back, and the control circuit (8a).

Input in (8b) and (8c). Generally, the gain of the control circuit is set to a large value in order to reduce steady-state deviation. The control circuits (8a), (8b), and (8c) each operate independently and perform negative calculations, and the selection circuit (4) removes the maximum and minimum values and outputs an intermediate value. Select quantity. As shown in Fig. 2, the selection circuit (4) selects the inner side of the output of the multi-control circuits (8a) and (8b) through the parallel circuit of reverse direction diodes (4at) and (4az). . Similarly, diode (4b+) −(
41'j) and (4CIL(4at>), the control circuit (
Select the internal size of the outputs of 8b) and (8c), (8c) and (8a). Furthermore, among the selected winter outputs, forward diodes (4ax), (4b).

By selecting the maximum value using (4cs), the one having the intermediate value is selected from among the eight outputs of each control circuit.

Next, the output of the selection circuit (4) is applied to the controlled object (6). In this way, a feedback control system with eight control circuits is realized.

Conventional multiplex control devices are configured as described above, so the hot water temperature response tends to be unstable due to the large gain of the control circuit, and the output of the control circuits not selected by the selection circuit is at risk of divergence and saturation. If there is a large output error with the selected control circuit, discontinuity will occur when switching the control circuit during maintenance, etc., and it will take time to reach a stable start.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and it is designed to keep the output of each control circuit within a certain range according to the difference between the output of the selection circuit and the output of each control circuit. It is an object of the present invention to provide a multiplex control device that can perform continuous switching of control circuits by making the following corrections.

An embodiment of the present invention will be described below with reference to the drawings.

In Section 8 (8), (6a), (6b), and (6o) are gain adjustment circuits with the same specifications, and FIG. 4 is a diagram showing the internal configuration of the gain adjustment circuit, (5at) is an adder, (6ξ ) is a limiter having a dead zone, (8ζ) is a driving element by a servo mechanism, and (5a2) is a t-i variable resistor.

Further, FIG. 5 shows teeth showing other embodiments, (7a), (W
b), (7c) are input adjustment circuits, (8a), (8b
) and (8c) are adders.

Next, the operation of the apparatus shown in FIGS. 8 and 4 will be explained. The process by which the outputs of the control circuits (8a), (8b), and (8c) are input to the selection circuit (4) and the control circuit having the intermediate value is selected is the same as in the conventional device.

The output of the selection circuit (4) is fed back to each control circuit, and the output of each control circuit is fed back to the gain adjustment circuit (6a).
, (6b), (6c) are input. The internal configuration of the gain adjustment circuit and the control circuit is the same as shown in FIG. 4, and the difference between the output of the selection circuit and the output of the control circuit is
The difference in d calculated in step l) is a limiter (6
-), if it is smaller than a predetermined value, the parameter correction of the control circuit is not performed, and if it is larger than a predetermined value, the variable resistance (
By operating 8a, the gain of each control circuit can be adjusted to keep the output of each control circuit within a certain range.

Note that although the above embodiment used a correction means of adjusting the gain constant in the control circuit, the same effect as in the above embodiment can be achieved even if other parameters in the circuit (time constant, limiter width, etc.) are corrected. Furthermore, in the above embodiment, the case of internal parameter correction of the control circuit was explained, but the calculation type of each control circuit is exactly the same, such as a digital μ processing circuit, and the A of the input section is
/ If the error of the D converter is considered to be the main cause, as shown in Fig. 6, a correction value corresponding to the difference between the output of the selection circuit and the output of each control circuit is input to the input adjustment circuit (7a), (
7b) and (7c), and the adders (8a) and (8b
), (8c) may be used to correct the input signal 1 to keep the output of each control circuit within a certain range.

Furthermore, although the present invention has been described using as an example a feedback control system in which the control circuits are 8-fold, the same applies to systems with 4-fold or higher circuits, and is also applicable to systems other than feedback control systems.

Note that if the output is outside the set range for a certain period of time due to a failure of the control circuit, it is not desirable to remove that circuit from the system.

As described above, according to the present invention, since the output of each control circuit can be corrected using the output of the selection circuit, the output of each control circuit can be kept within a certain range.
This has the effect of providing a control circuit that can be switched continuously.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional multiplex control device, FIG. 2 is a block diagram of a selection circuit, FIG. 8 is a block diagram of a multiplex control device showing an embodiment of the present invention, and FIG. 4 is a block diagram of a conventional multiplex control device. FIG. 5 is a block diagram of a multiplexing control device showing another embodiment of the present invention. In the figure (
1) is a target value setter, (2) is an adder, (8a), (8
b), (8c) are control circuits, (4) are selection circuits, (5)
is the controlled object, (6a), (6b) (6o) is the gain adjustment circuit, (Sat) is the adder, C6''t) is the limiter, (8a1) is the driving element, and (δξ variable resistance). Middle figure - Codes indicate the same or corresponding parts. Agent Makoto Kuzuno - (1 other person)

Claims (1)

[Claims] a plurality of control circuits that generate signals to control a controlled object;
It is equipped with a selection circuit that selects the optimal one among the outputs of these control circuits, and a correction circuit that limits the output range of each control circuit according to the difference between the output selected by this selection circuit and the output of each control circuit. Multiplex control equipment.