JPS6158004A - Automatic controller - Google Patents

Abstract

PURPOSE:To expand the applied range and to attain simple adjustment by controlling a drive motor so as to quicken gradually the moving speed of a final control element when a time where the result of detection is deviated from an object is longer, while it is regarded that the deviation is large. CONSTITUTION:A damper 3 controlling cold/hot air volume led from a heat exchanger to a duct is driven by a reversible motor 10 by using a control cir cuit. A common contact (a) of a changeover switch 12 as a 3-position regulator is moved by a diaphragm 4 and connected to any of highstatic pressure contact (b)-(d). In this case, relays 20a, 20b detecting the the state of said contacts (b),(d), an unequal interval pulse generating circuit 22 and relay contacts 24a, 24b are provided. When the common contact (a) of the changeover switch 12 is thrown to the contact (b), the relay 20b is activated, the contact is closed, a pulse of unequal interval is generated from said pulse generating circuit 22 to open the relay contact 24b thereby increasing the movement of the motor 10 per unit time as time increases.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic control device used in an air conditioning system or the like.

[Prior art and problems to be solved]

Conventionally, single-speed control devices have been used for static pressure control in air conditioning ducts with small dead time and small time constant, and for water level control in tanks where the quality of the control results is not very important.

Figures 5 and 6 show examples of this in the case of static pressure control.
This will be explained with reference to the figures. In FIG. 5, reference numeral 1 denotes a heat exchanger, and a cold/hot air discharge port of the heat exchanger 1 is connected to a duct 2 for transporting cold/hot air to a space to be air-conditioned. Inside the duct 2 near the cold and hot air discharge port, there is a damper 3 as an operating end for controlling the amount of cold and hot air introduced into the duct 2 from the heat exchanger 1, and a static pressure detection end provided on the downstream side of the damper 3. A diaphragm 4 of a pressure sensor is housed therein. Note that 5a and 5b are normally closed rim switches that detect when the damper 3 is fully closed and fully open, respectively;
is a blower motor for discharging cold and hot air from the heat exchanger 1 to the duct 2.

FIG. 6 shows a control circuit that controls opening and closing of the damper 3,
In the figure, 10 is a forward/reverse rotating motor having a forward rotating coil 10a and a reverse rotating coil 10b, and drives the damper 3 which is operated by αj(, 1) via a reduction gear, a link mechanism, etc. This is a changeover switch that functions as a three-position switch, and when the common contact a is moved by the diaphragm 4, it becomes the high static pressure contact b and the neutral contact C1.
Connected to one of the low static pressure contacts d. 14 is a commercial power supply.

In the illustrated circuit, when the damper 3 is not fully open or fully open and the limit switches 5a and 5b are closed, the common contact a is set to low static pressure in response to detection of low pressure by the static pressure detection terminal. When connected to the pressure contact d, current from the commercial power supply 14 is passed through the limit switch 5b to the reversing coil 10b, causing the motor 10 to rotate in the reverse direction.

This reverse rotation of the motor 10 drives the damper 3 in the fully open direction. Due to this driving of the damper 3, the static pressure at the static pressure detection end increases, and in response, the diaphragm 4 operates the switch 12 to change the common contact a to the neutral contact C.
to stop the current from flowing through the motor 10 and stop its rotation.

Contrary to the above case, when high static pressure is detected by the detection end, the common contact a is connected to the high static pressure contact A, current is passed through the forward rotation coil 10a through the limit switch 5a, and the motor 10 is started. The damper 3 is rotated in the forward direction, and the damper 3 is accordingly driven in the fully closed direction. By driving this damper 3, the static pressure at the detection end is lowered, and in response, the common contact a of the switch 12 is connected to the neutral contact C, and the motor 10
rotation is stopped.

In the above-described operation, unless the opening/closing speed of the damper is changed according to the dead time or time constant of the system, or the speed of disturbance, the quality of control may become unusable. This work to change the damper speed is carried out on site through trial and error, such as changing the gear ratio of the reduction gear and changing the energization time to the motor using an intermittent timer, to achieve the optimum state.

In the case of changing the gear ratio, there is a drawback that the range of use is extremely narrow because the types of changes are limited.

On the other hand, in the case of an intermittent timer with a fixed period, the on-time and off-time are adjusted according to the dead time and time constant of the system, regardless of the size of the deviation, so it requires considerable skill and time to select the optimal value. Therefore, it lacks killing properties and is only used in limited systems, such as temperature control of the air blown out of VAV equipment in the air conditioning field.

[Means for solving problems]

The present invention provides an automatic control device that solves the problems of the conventional ones described above, and its means include a detection end for detecting a control result, a detection result by the detection end with a target, and a resultant result. a regulator that sends out three-position outputs in accordance with the output of the regulator, an unequal-interval pulse generating means that generates pulses with unequal intervals that change over time in accordance with the output of the regulator, and a drive motor that drives the operating end. , by an automatic control device characterized in that the motor is controlled by the irregularly spaced pulses so that the amount of movement of the operating end per unit time increases with time.

[For production]

The movement speed of the operating end can be determined according to the length of time that the detection result deviates from the target, and the change pattern of this movement speed can be easily changed using a pattern of irregularly spaced pulses, so it is suitable for branch offices. The range is expanded, and adjustments can be easily made depending on the system.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a wiring diagram showing an embodiment of an automatic control device according to the present invention applied to static pressure control, and parts equivalent to those in FIG. 6 are given the same reference numerals.

In FIG. 1, relays 20a and 20b detect the states of contacts A and D of the changeover switch 12, which are regulator outputs.
is connected between the contacts and d and the commercial type 'tA14,
Relay contacts 24a and 24b, which are opened by irregularly spaced pulses generated by the irregularly spaced pulse generating circuit 22 in response to the operation of the relays 20a and 20b, are connected between limit switches 5a and 5b and contacts 1 and d. The other parts are the same as the circuit shown in FIG. 6, except that the circuit shown in FIG.

FIG. 2 shows a specific circuit side of the unequal pulse generating circuit 22. As shown in FIG. In the figure, 20a' and 20b' are normally open contacts of relays 20a and 20b, which are closed by the operation of the relays. Contacts 20a' and 20b' are connected in parallel, with one end connected to the +power supply via a resistor R1, and the other end connected to ground.

22a is a clock pulse generation circuit whose enable input terminal is connected to one end of contacts 20a' and 20b' via an inverter 22b;
When the enable input terminal becomes H level due to the closing of , the operation starts and a clock pulse with a frequency corresponding to the value of the variable resistor VRO is outputted.

22c is a hexadecimal counter that counts the clock pulses from the clock pulse generation circuit 22a, and the output of the NAND circuit 22d is connected to the reset input terminal R, and in response to the fall of the reset input terminal from H to L level. will be reset.

22e is a 16-bit multiplexer, and when its strobe input S is at L level, it sequentially sends out the focus state specified by the output of counter 22c added to its parallel input, that is, H and L levels.

22f is an R-S flip-flop, the output of the one-shot multi-by-break 22g is connected to the set input S, and the output of the NAND circuit 22h is connected to the reset input R. The one-shot multi-by-break 22g has an input of I(
In response to the change from the low level to the low level, a high level pulse is generated at the output, and the J9R-S flip-flop 22f is set at the rising edge of the pulse. The output of the counter 22c is connected to the input of the NAND circuit 22h, and in response to all of its inputs becoming H level, its output falls from H level to L level, thereby resetting the R-S flip-flop 22f. do.

The Q output of the t5R-S flip-flop 22f is connected to the other input of a NAND circuit 22d, one input of which is connected to the output of the inverter 22b. Therefore, when one of the relay contacts 20a' or 20b' closes, the R-S flip-flop 22f is turned on, and both inputs of the NAND circuit 22d become H level, the counter 22c is reset and the counter 22c is reset. The total output becomes O.

The third input of the NAND circuit 22i, to which the Q output of the R-S flip-flop 22f and the output of the 16-bit multiplexer 22g are connected to the first and second inputs, respectively, has a The connection point between the connected resistor R2 and the normally open manual switch 22j is connected, and the output of the NAND circuit 22i is connected to N through the resistor R3.
PN Connected to the base of transistor Q. An output relay coil 24 is connected to the collector of the transistor Q, and when energized, the relay coil 24 closes the normally open relay contacts 24a and 24b.

In the above configuration, the operation will be explained with reference to FIG. 3 showing waveforms of each part.

Now, the common contact a of the changeover switch 12 is changed to the contact d at time t1.
In response to this, the relay 20b is activated and its contact 20b' is closed. In response, the clock pulse generation circuit 22a sends out the clock pulse shown in FIG. 3(A).

At the same time, the one-shot multi-by-break 22g is triggered by the fall of its input from H to L level as shown in FIG. Cent the S flip-flop 22f.

As a result, the Q output of the R-S flip-flop 22r rises from L to H level as shown in FIG. 3(D).

Clock pulses from the clock pulse generation circuit 22a are applied to a counter 22c and counted.

When the counter 22c counts the first pulse, the multiplexer 22 specified by the output of the counter 22c
The L level of the bit in e is output as shown in FIG. 3(C). When the second (second) pulse is counted, an H level is output to the output of the multiplexer 22e. From then on, depending on the count of 3 to 16 pulses, the number of pulses is set at unequal intervals as shown in FIG. 3(C). pulses are sent to the output of 16-bit multiplexer 22e.

At time t2 when 16 clock pulses are counted by the counter 22c and its total output becomes "1", the output of the NAND circuit 22h goes from H to L level, the R-S flip-flop 22f is reset and its output is shown in Figure 3 (
As shown in D), the level changes from H to L level.

As mentioned above, the output of the multiplexer 22e and the output of the R-S flip-flop 22f are applied to the NAND circuit 22i, so the output of the NAND circuit 22i is as shown in FIG.
As shown in E), during the period when the R-S flip-flop 22f is sent, the 16-bit multiplexer 22e
An inverted version of the irregularly spaced pulses which is the output of is output.

Since the transistor Q, to which the output of the NAND circuit 22i is applied to its base, is turned on at H level and turned off at L level, the relay coil 24 is no longer energized each time an irregularly spaced pulse is generated, and the relay contact 24a and 24b are turned off. The frequency with which the relay contacts 24a and 24b turn off becomes smaller as time passes after the contact of the switch 12, which is the regulator output, switches from the neutral point and the correction operation is started. Then, after a predetermined period of time, that is, after the counter 22c counts 16 clock pulses and the R-S flip-flop 22f is reset in response, it does not turn off at all.

By turning off the relay contacts 24a and 24b, the coils IQa and 10b of the motor 10 are no longer energized.
Since the rotation of the motor 10 is temporarily stopped, the moving speed of the damper 3 is slow immediately after the motor 10 starts rotating. Switch 12, which takes time to correct and is the regulator output
The longer the time that the damper 3 is away from the neutral point, the faster the moving speed of the damper 3 gradually becomes, reaching the maximum constant speed after a predetermined period of time.

The manual switch 22j forcibly sets the third input of the NAND circuit 22i to L level, thereby preventing the transistor Q from being turned off by irregularly spaced pulses from the multiplexer 22e, thereby impairing the function of the multiplexer 22e, and correcting the is performed at a constant speed.

As the corrective operation progresses and the damper 3 is moved to the desired position, the switch 12, which is the regulator output, switches to the neutral contact C, and the contact 20b' of the relay 20b is turned off, which causes the clock pulse generation circuit 22a1 counter 2 to turn off.
2C1 multiplexer 22e stops operating. At this time, if the R-S flip-flop 22f is reset, the transistor Q is turned on, and the relay contacts 24a and 2
4b are both on, but the switch 12 shuts off and power is not supplied to the motor 10, so the damper 3
movement is stopped.

Note that the strobe input of the multiplexer 22e is L.
When the level is reached, the output becomes H level.

The above explanation of the operation was made for the case where the switch 12, which is the regulator output, switches to the contact d side, but when the switch 12 switches to the contact d side, the relay 203 operates, and the contact 20a responds to this. ' is turned on, and the irregularly spaced pulse generating circuit 22 begins to operate in the same manner as described above.

FIG. 4 shows a partial modification of FIG. 2, in which the 16-bit multiplexer 22e is replaced with a read-only memory (
ROM) 22k is used to generate finer irregularly spaced pulses. A pattern selection circuit 22β is connected to the ROM 22k, and the selection circuit 221 can select one of a plurality of types of irregularly spaced pulses. Further, when this ROM 22k is used, the final bit condition can also be stored in the ROM 22k, and the R-S flip-flop 22f can be reset by reading it.

In the above embodiment, the output of the switch, which is the regulator output, is detected by a relay, and a relay is also used at the output end of the unequal interval pulse generation circuit 22, but these relays may be replaced with semiconductor switches or the like. can be done.

〔Effect of the invention〕

As explained above, according to the present invention, the moving speed of the operating end is constant and is unrelated to the magnitude of the deviation between the target and the detection result, whereas in the present invention, the detection result is different from the target. The deviation is large when the operating end is disconnected for a long time, so the movement speed of the operating end is gradually increased by controlling the energization time per unit time to the operating end drive motor, expanding the range of systems that can be used. At the same time, you can easily make adjustments to suit your system.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing the overall configuration of an embodiment of the present invention, Fig. 2 is a circuit diagram showing a specific example of a part of Fig. 1, and Fig. 3 shows waveforms of each part in Fig. 2. FIG. 4 is a circuit diagram showing a part of the waveform in FIG. 2, and FIGS. 5 and 6 are diagrams showing an example of the conventional waveform. 3...Dunbar, 4...Diaphragm, 10...Forward/reverse rotation motor, 12...
Changeover switch, 22...Unequally spaced pulse generation circuit.

Claims (1)

[Claims] A detection end that detects the control result, a regulator that compares the detection result of the detection end with a target and sends out three-position outputs according to the results, and an unequal interval that changes over time according to the output of the regulator. and a drive motor for driving the operating end, the motor being controlled by the irregularly spaced pulses to increase the amount of movement of the operating end per unit time over time. An automatic control device characterized by: