JPH0324685B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a water level detection device that detects the water level of a water storage section, a water amount adjustment device that controls the amount of water supplied to or discharged from the water storage section, and a water amount adjustment device that controls the water amount based on information from the water level detection device. A first control device that automatically controls the aperture and opening of the device; and a second control device that automatically controls the opening and return of the water amount adjusting device based on information from the water level detection device; The first control adjustment is performed while the water level of the water storage section is out of the set range to the high water level side and while the water level is out of the set range to the low water level side, the water amount adjusting device is operated to restore the water level to the set range. The second control device is controlled by the pulse signal transmitted by the first control device, and the second control device is controlled by the pulse signal transmitted by the first control device, and the second control device is controlled by the pulse signal transmitted by the first control device. The present invention relates to a water level control device that is linked to the water amount adjusting device so as to apply a control signal to the water amount adjusting device to control the water amount adjusting device to open back or squeeze back in the opposite direction.

The above water level control device maintains the water level in the water storage part within a set range, for example, in water supply systems such as waterworks and industrial water, so that water can be supplied with almost constant water pressure regardless of fluctuations in the amount of water used. used to make

This water level control device is designed to control the water level when the water level exceeds the upper limit of the set range due to fluctuations in drainage volume.
The first control device intermittently controls the water amount regulating device for controlling the amount of water supplied to the water storage section in the throttle direction by pulse control, and when the water level is restored to within the set range, the water amount regulating device is operated. If this control state is left as it is, the water level will immediately exceed the lower limit of the set range and hunting control will be performed, so the second control device returns the water amount adjusting device to control. The water flow control device is controlled based on the water level detection information.
The initial cost can be significantly reduced compared to analog control devices such as PID control.

However, conventionally, the return control by the second control device was performed by one pulse signal at a predetermined time, that is, the return control was performed for a fixed time regardless of the amount of water level fluctuation. As a result, the control amount tends to be too large or too small, and as a result, the water level deviates from the set range within a short period of time, making it difficult to perform stable control.

In view of the above-mentioned circumstances, an object of the present invention is to make it possible to accurately and stably restore the water level within a set range by simple modification.

The present invention provides the water level control device described above, wherein the second control device is equipped with a pulse transmission number measuring device and a pulse transmission device, and the measuring device is configured to operate when the water level of the water storage section is outside the set range. The first control device is linked to the first control device so as to measure the number of times the first control device transmits the pulse signal during the period, and the pulse transmission device of the second control device is connected to the first control device so as to measure the number of times the first control device transmits the pulse signal. After restoring within
Linked to the water amount regulating device so that the same number of pulse signals as the number of measurements by the measuring device are given to the water amount regulating device as the return control signal, and transmitted by the pulse transmitting device of the second control device. One of the pulse signals transmitted by the first control device controls the opening and opening of the water volume regulating device. It is characterized by being formed almost in half.

The effects of the characteristic configuration of the present invention are as follows.

That is, in a state where the water level has been restored to within the set range l, the amount of water supplied and the amount of water discharged are approximately balanced by returning the water amount adjusting device 4 for approximately half of the control time for the water amount adjusting device 4 for that purpose. The first control device 8 transmits a pulse signal a, and the pulse signal a causes the water flow control device 4 to operate in the throttle direction or the opening direction according to the total time. By changing the time period during which the second control device 9 returns the water volume adjustment device 4 to the opening direction or the throttle direction, it becomes easier to accurately and stably maintain the restored water level within the set range l.

Furthermore, it is conceivable to perform PID control on the water flow rate adjusting device 4, for example, but this would make the control system a little more complex and would likely result in poor return control accuracy. In other words, in a general PID control device, in the D (differential) control in PID, the amount of operation is determined by the magnitude of the rate of change in water level, but if the direction of change in water level approaches the set value, for example The rate of change in the water level changes from positive to negative, and the direction of operation is reversed, so the amount of operation changes as the rate of change changes.
Water level control using such a PID control system is performed not only by D control, but also by proportional P control and integral I control, so even if the water level returns to the set value, P and I control are not performed. This causes the control to go beyond the set range, and generally the control ends up exceeding the set range several times and then gradually coming back within the set range. In contrast, according to the present invention, the return control is performed by pulse control and by changing the number of emitted pulses, thereby making it possible to avoid complication of the control system, and to perform return control smoothly and accurately. It worked well, and overall, with simple improvements, it became possible to control the water level with high precision.

Next, examples will be shown.

A water supply pipe 3 from a water supply pump P is connected to a water storage part 2 to which a drain pipe 1 is connected, and a water flow rate adjustment device 4 comprises a flow rate control valve V and a drive motor M for adjusting its opening degree.
The control valve V is interposed in the water supply pipe 3, and the control unit 6 of the motor M is provided with a water level control device 5 that detects water level fluctuations in the water storage unit 2 and maintains the water level within a set range. In conjunction with each other, a water distribution facility is constructed in which the water pressure in the water distribution pipe 1 is kept approximately constant.

The water level control device 5 restores the water level to within the set range based on the device 7 that detects the water level of the water storage section 2 and the water level detection information from the water level detecting device 7 indicating that the water level is out of the set range. a first control device 8 that intermittently controls the water amount regulating device 4 using a pulse signal; and after the water level is restored within a set range, the water amount regulating device 4 is controlled in a direction opposite to the previous control thereof; It is comprised of a second control device 9 that performs return control using pulse signals.

The water level detecting device 7 is configured with a water level setting device 10 for changing and setting the water level in a certain range to be detected, that is, for changing and setting the upper and lower limits of the detected water level. A float type water level detector 11 for detecting water level fluctuations is attached to the water storage section 2, and the information from this detector 11 is inputted to the discriminating device 12 through the water level setting device 10, and by this discriminating device 12, It is determined whether the water level in the water storage section 2 is within a set range.

Then, the first control device 8 is made to input detection information that the water level has gone out of the set range, and the second control device 9 is made to input water level restoration information that the water level has been restored to within the set range. There is.

The first control device 8 controls the water amount adjusting device 4 by sending a pulse signal a that automatically throttles or opens the water amount adjusting device 4 based on information that the water level detecting device 7 is out of the setting range. 6, the control valve V is directed to close based on the information that the water level has exceeded the upper limit of the setting range, and
The opening of the control valve V is intermittently adjusted in small increments in the opening direction based on the information that the water level has fallen below the lower limit of the set range.For example, when the water level exceeds the upper limit of the set range. Assuming that, as shown in Figure 2, if you input information that the water level has exceeded the upper limit H of the setting range L, a certain set time of about 2 minutes, for example, will be displayed until the input is no longer received. A valve closing control signal a for a preset time t, for example, about 2 minutes, is inputted to the motor control unit 6 of the water flow regulating device 4 every time T..., and the pulse signal a causes the valve to close slightly. The control valve V is controlled to throttle intermittently. That is, each time one pulse signal a is applied to the control unit 6, the control valve V is operated in the closing direction for a time determined by the set control time t of the pulse signal a,
The opening degree of the control valve V is reduced from before the pulse signal a is transmitted by a small opening degree proportional to a set control time t, which is provided as the time for controlling the closing of the control valve V in the pulse signal a. And pulse signal a
While not transmitting the pulse signal a, the control valve V maintains the opening degree that the control valve V has had for controlling the closing direction by transmitting the pulse signal a. In other words, from the time the water level goes out of the set range l until it returns to the set range l, the control valve V is intermittently controlled in the closing direction by small openings, and the small opening is closed by one pulse signal a. It accumulates.

The second control device 9 is linked to a measuring device 13 linked to the first control device 8, this measuring device 13, the discrimination device 12 of the water amount detecting device 7, and the control unit 6 of the water amount adjusting device 4. The pulse transmitter 14 transmits a pulse signal from the first control device 8 when the water level is restored to the set range l and the final set time T of pulse transmission by the first control device 8 has elapsed. By applying a pulse signal b to the water amount adjusting device 4 as a return control signal for opening and returning the water amount adjusting device 4 in the opposite direction to the control by a, the first control device 8
When the first control device 8 operates to close the control valve V, the first control device 8 causes the control valve V to open by an amount equivalent to approximately half of the control valve V that was closed. , the control valve V is closed by an amount corresponding to approximately half of the control valve V opened by the first control device 8.

That is, the measuring device 13 uses the first control device to restore the water level to the set range l while the water level of the water storage section 2 is out of the set range l based on the information from the discrimination device 12 and the first control device 8. 8 is configured to measure the number of times N that the pulse signal a is transmitted. When the water level is restored to the set range l and receives a water level restoration signal from the discriminator 12, and the final set time T for pulse transmission by the first control device 8 has elapsed, the pulse transmitter 14 transmits the measuring device 13. The same number of pulse signals b as the number of measured pulses N...
is configured to be transmitted to the control unit 6 at a short period T ₁ , and at the time of this pulse transmission, a set control time t ₁ is set to provide the pulse signal b as a time for controlling the opening or closing of the control valve V. The pulse signal a is formed to be approximately half of the set control time t of the pulse signal a by the control device 8.

In other words, assuming that the water level exceeds the upper limit of the set range, each time one pulse signal b is applied to the control unit 6, the control valve V is controlled for the set control time t ₁ of the pulse signal b, as shown in FIG. The opening of the control valve V is increased by a small opening proportional to the set control time _t1 of the pulse signal b compared to that before the pulse signal b was transmitted. Then, while pulse signal b is not transmitted,
This causes the control valve V to maintain the opening degree that the control valve V has had due to the control of the opening direction by the transmission of the pulse signal b. Eventually, when the water level is restored to the set range l, the first control device 8 transmits a pulse signal a, intermittently opening the control valve V by approximately half of the small opening controlled by the pulse signal a. Control is performed in the opening direction with the same number of control times as the number of times, and the openings caused by one pulse signal b are accumulated. Since the set control time t ₁ of the pulse signal b is approximately half the set control time t of the pulse signal a, and the number of times the pulse signal b is transmitted is the same as the number N of times the pulse signal a is transmitted, the The amount of operation performed by the second control device 9 to open and return the control valve V is approximately half the amount of operation performed by the first control device 8 to close it.

That is, as shown in FIG. 2, near the reversal point Q of the water level change due to the intermittent closing operation of the control valve V,
It was discovered that the amount of water supplied and the amount of water distributed are almost in balance, which means that if the control valve V is maintained at an opening near its reversal point Q, the angle of inclination at which the water level changes will be gradual. Therefore, when the water level is restored to the set range l by the first control device 8, by correcting the opening degree of the control valve V to the opening degree near the reversal point Q. , the water level can be stably maintained within the set range l for a long period of time.

Next, another example will be shown.

The total time T ₀ of the return control according to the above explanation can be expressed by the following formula: T ₀ ≒ N/2×t () N: Number of pulse measurements t: Set control time, but as shown in FIG. 3, When the number of times of control by the first control device 8, that is, the number of pulse measurements N is an odd number, the inclination angle at which the water level changes immediately after the reversal point Q of the position shown in FIG. 3 becomes the most gradual. That is, when the number N of pulse measurements is an odd number, it is preferable to control the total time T ₀ of the return control so that T ₀ ≈N/2×t+t/2 (). If a mechanism is provided to determine whether the measurement result is an odd number or an even number, and based on the result, the formula () or () is selected and the control valve V is returned to control, the water level will be further stabilized. This is advantageous in terms of control accuracy because it can be maintained within the set range l. Therefore, when carrying out the present invention, the total time for transmitting the pulse signal b for return control is
It is preferable to set T ₀ based on the above equations () and ().

Further, in the present invention, the amount of water supplied is adjusted by adjusting the opening degree of the control valve V, but the water supply pump P is of a variable displacement type and is controlled by the first and second control devices 8 and 9. Therefore, it may be controlled, i.e.,
The specific configuration of the water amount adjustment device 4 can be modified in various ways.

In addition, by combining a device that transmits two types of pulse signals a and b and a discriminating device 12, the pulse signal a and , the pulse signal b is transmitted based on the information that the water level has been restored within the set range l, and of course the measuring device 13 is linked to it, and one pulse transmitting device is also used to transmit the pulse signal b. It is also possible to configure the first and second control devices 8 and 9 for implementation.

Furthermore, the present invention can also be applied to systems in which the water level control device 4 controls the amount of water discharged, such as maintaining the water level of a dam at a substantially constant level, and the water level control device 5 can be installed in any manner.

[Brief explanation of the drawing]

The drawings show an embodiment of the water level control device according to the present invention, and FIG. 1 is a schematic overall view of water distribution equipment, and FIGS. 2 and 3 are illustrations of control for water volume adjustment, respectively. 2...Water storage unit, 4...Water volume adjustment device, 7...Water level detection device, 8...First control device, 9...Second control device, 13...Measuring device, 14...Pulse transmitter, a , b...Pulse signal, l...Setting range,
N...Number of times, t, _t1 ...Time.

Claims (1)

[Claims] 1. A water level detection device 7 that detects the water level of the water storage section 2;
A water amount regulating device 4 that controls the amount of water supplied or drained to the water storage section 2, a first control device 8 that automatically controls the water amount regulating device 4 to throttle and open based on information from the water level detecting device 7, and A second control device 9 is provided which automatically controls the water flow rate adjustment device 4 to open and return on the basis of information from the water level detection device 7, and controls the first control device 8 to control the water level in the water storage section 2. While the water level deviates from the setting range l to the high water level side, and
While the water level is off to the low water level side, the water level is kept within the setting range l.
The second control device 9 is linked to the water amount adjustment device 4 so as to intermittently apply a pulse signal a to the water amount adjustment device 4 to control the water level adjustment device 4 to throttle or open the water level adjustment device 4 so as to restore the water level to the original state. The controller is configured to apply a return control signal to the water amount adjusting device 4 to open the water amount adjusting device 4 in the opposite direction to the control based on the pulse signal a transmitted by the first control device 8. The water level control device is linked to the water amount adjusting device 4, and the second control device 9 is equipped with a pulse transmission number measuring device 13 and a pulse transmitting device 14, and the measuring device 13 is connected to the water level of the water storage section 2. is linked to the first control device 4 so as to measure the number of times N that the first control device 4 transmits the pulse signal a while the pulse signal a is out of the setting range l; Pulse transmitter 14
After the water level of the water storage section 2 is restored to within the set range l, the pulse signal b of the same number as the number of measurements N by the measuring device 13 is applied to the water amount adjusting device 4 as the return control signal. The pulse transmitting device 14 of the second control device 9 is linked to the water amount adjusting device 4.
The one pulse signal a transmitted by the first control device 4 controls the opening-return control and the throttle-return control of the water amount adjusting device 4 at a time t ₁ for which the one pulse signal b transmitted by the first control device 4 The water level control device is formed at approximately half of the time t for controlling the water amount adjusting device 4 to throttle and open.