JPH0319629A - Controlling equipment of nutritive solution for water-culturing - Google Patents

Abstract

PURPOSE:To quickly detect abnormality of nutritive solution and prevent trouble giving bad influence to crop by stopping controlling action for detecting of deviation of nutritive solution concentration from normal region with alerting and simultaneously returning to normal region. CONSTITUTION:Electroconductivity detected by concentration sensor 6 as a substituting value of fertilizer concentration is inputted into amplifier 23 and stored in CPU: 22b as a detected value through AD converter, then said detected value is compared with alerting values of upper and lower limits previously stored in RAM: 22d. The detected value is compared with fixed lower limit value in a case of not abnormal region and operating condition of side dressing is calculated in a case of falling below fixed lower limit value, then side dressing time proportional to deviation between the detected value and the fixed lower limit value is calculated and added to integrated timing value of side dressing signal in a case of materializing of operating condition, thus resultant timing is compared with reference timing set to sufficiently returning into normal region of fertilizer concentration in the nutritive solution by the action of fertilizer-solution mixing device. Then for a case abnormal performing of side dressing or not detecting of recovery of fertilizer concentration into normal region, alerting device 21 is operated and control is simultaneously stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement of a control device for controlling the concentration and temperature of a nutrient solution for hydroponic cultivation.

<Prior Art> FIG. 7 is a schematic structural diagram of a nutrient solution control device designed to control fertilizer concentration. In the figure, 31 is a nutrient solution tank;
7 is a nutrient solution, 33 is a west pipe, 3.1 is a bomb, and the nutrient solution is passed through the pipe 33 from the bomb 34{5-. C outside the figure: Culture section 1. r. {． l. C-paid. 35 is piping 33
The nutrient solution is supplied via the target branch pipe 33a from the nutrient solution to the fertilizer 4f, which detects the fertilizer concentration of the nutrient solution.
37 is a liquid fertilizer mixer equipped with a metering bomb or the like, and 38 is a control device.

The sensor 36 is placed in the sensor point 1, 35 so that it can measure 5I after the nutrient solution has been stirred for -4 minutes, and the detected fertilizer concentration is set to the set value by the control device 1α38. Compare with 2. Liquid fertilizer mixing device: Controls 37 and operates to keep the fertilizer content within a predetermined range.

In the case of such control, - Generally, 1 as shown in Fig. 8 is used.
−． A limit setting A and a lower limit set value are set, and the area between them is defined as a correct area.Furthermore, a H limit alarm value and an F limit alarm value are set above and below the range, and the range between each set value is It is configured as an adjustment area, and when the detected value exceeds the alarm value and enters the abnormal area, an alarm is output and the control is stopped.In this way, when the detected value exceeds the alarm value and enters the abnormal area When the control stops!}・, the width of the adjustment region cannot be made very small.In addition, in order to perform stable control, an insensitivity is provided in the stop region L1. ．Sometimes.

<Problem to be solved by invention> Above. For a system l1 configured as follows, (a)i
EL. <Measured but ir: Not always working (
(For example, a malfunction of a sensor bomb, out of liquid fertilizer, a pipe is out of stock, etc.) (b) Since the measurements are not correct, the operation cannot be said to be correct.
In general, there are two types of abnormalities: (new #: liquid does not flow, etc.). And above (
In case a), abnormality cannot be detected unless the detected value reaches a level that deviates considerably from the set value.

In the case of (b), if the faulty sensor outputs an output that is significantly below or below the alarm value, it is possible to detect an abnormality, or if the output value happens to be within the alarm value, it is abnormal. It can only be detected. In addition, a hull 39 provided in the branch pipe 33a
If the sensor is closed, new nutrient solution will not flow into the sensor, so the same nutrient solution may remain in the same state forever, or the sensor may stand out from the nutrient solution, causing actual problems. This means that even if something is abnormal or alive, it will not be detected. For this reason, for example, control in the direction of increasing the fertilizer concentration will continue, resulting in a problem that the fertilizer concentration will not become extremely high.

In general, in the case of hydroponic cultivation, it is necessary to appropriately control the fertilizer concentration according to the growth stage of the crop, and if no abnormality is detected during the above-mentioned process, the crop may be adversely affected. In particular, if the fertilizer concentration becomes too high, fruits may become overripe, deformed, root rot, etc., resulting in large economic losses. Incidentally, such a negative effect on crops occurs not only in the fertilizer concentration but also in the case of abnormalities such as 1) I and temperature of the nutrient solution.

The present invention has been made to address these problems and to promptly detect abnormalities in the nutrient solution to prevent troubles that would adversely affect crops.

4 <A Thousand Steps to Solve the Problem> In order to achieve the above-mentioned 11th objective, the first invention provides a thousand steps for detecting the concentration of a nutrient solution for hydroponic cultivation; When the means detects that the concentration of the nutrient solution is out of the normal range, the concentration adjustment means operates to return the concentration of the nutrient solution to the normal range, and the time integration means integrates the operating time of the suki adjustment means. If it is detected that the concentration of the nutrient solution is out of the normal range when the cumulative value of the operation time of the concentration adjustment means reaches a preset reference time, it is determined that there is an abnormality, and the control operation is stopped and an alarm is issued. and a determination means for emitting.

Further, in the second invention, the nutrient solution temperature detection means detects the temperature of the nutrient solution, and when it is detected that the nutrient solution temperature is out of the normal range, it operates to return the nutrient solution thirst to the normal range. The temperature adjustment means, the time integration means for integrating the operating time of the temperature yA adjustment means, and the nutrient solution temperature is out of the normal range when the integrated value of the operation time of the temperature adjustment means reaches a preset reference time. and a determining means that determines that there is an abnormality, stops the control operation, and issues an alarm.

Figure 2 is a diagram showing the structure of the present invention, where A is a nutrient solution concentration (or temperature) detection means, B is a concentration (or temperature) adjustment means, C is a time integration means, and D is a determination means. E indicates a control unit that controls the entire device including the above-mentioned means, and F indicates an alarm device.

The reference time used to determine an abnormality takes into consideration the capacity of the nutrient tank that makes up the system, the ability of the concentration adjustment means or temperature adjustment means, the margin between the upper and lower set values, etc. However, the concentration or temperature of the nutrient solution is set to a value such that the concentration or temperature of the nutrient solution returns to within the normal range if the adjustment means operates for that period of time.

Therefore, in the case of the invention No. ↓, the fact that the concentration of the nutrient solution is out of the normal range even though the concentration adjustment means has operated for that period of time means that some abnormality is considered to have occurred. Therefore, it is possible to detect any of the above abnormalities (a) and (b). In this invention, the term "concentration" is used to include r P H J.

? The same applies to the second invention, and the fact that the temperature of the nutrient solution is out of the normal range even though the temperature adjustment means has been activated for that period of time means that some abnormality is considered to be occurring. Therefore, both of the above abnormalities (a) and (b) are detected.

<Example> Next, an example of the present invention will be described. This embodiment is an example of an apparatus that has both the functions of concentration control for detecting a decrease in the fertilizer concentration of the nutrient solution and performing additional fertilization, and temperature control for detecting a decrease in the temperature of the nutrient solution and heating it.

FIGS. 2(a) and 2(b) are diagrams illustrating the structure of the invention shown in the upper figure in slightly more detail by dividing it into concentration control and temperature control. That is, in the figure (a), A■ is the fertilizer concentration detection means, B1 is the liquid fertilizer mixing device, C is the top dressing signal integration means, and D
, is an additional fertilizing abnormality determining means, Fe is an alarm device, G is an additional fertilizing signal generating means, and H1 is an additional fertilizing signal integrated value reset means. In addition, in the figure (b), A2 is the nutrient solution temperature detection means, and B2 is the nutrient solution temperature detection means.
is a nutrient solution heating device, C2 is a heating signal integration means, D2 is a heating abnormality determination means, F2 is an alarm device, G2 is a heating signal generation means, and H2 is a heating 7 signal integrated value reset means.

FIG. 3 is a schematic diagram of the apparatus of the embodiment. In the figure, 1
2 is a nutrient solution tank, 2 is a nutrient solution, 3 is a pipe, and 4 is a pump. The nutrient solution is supplied by the pump 4 through the pipe 3 to a cultivation section not shown. 5 is a sensor pot to which the nutrient solution is supplied through a branch pipe 3a from the pipe 3; 6 is a concentration sensor using a conductivity meter, etc.; 7 is a liquid fertilizer mixing device composed of a metering pump, etc.;
9 is a control device, and 9 is a valve provided in the branch pipe 3a. Although the concentration sensor 6 described above is arranged in the sensor pots 1 to 5, it can also be arranged directly in the nutrient solution tank 1 depending on the case. Further, 11 is a liquid temperature sensor such as a thermistor, 12 is a liquid temperature adjustment device equipped with a heat medium heating function,
13 is a heat exchanger, and the heat exchanger 13 is arranged in the nutrient solution tank 1 so that the heat medium heated by the solution temperature adjustment device 12 circulates therethrough. 4 is piping, and 15 is a circulation pump.

FIG. 4 is a block diagram of the device of the embodiment.

In the figure, 21 is an alarm device, 22 is a microcomputer which constitutes the main part of the control device 88, and 23 is an amplifier. The microcomputer 22 is connected to the input port 1
- AD converter 22a, CPU 2 which is the center of control
2b, ROM that stores control programs, etc. 2 2
c, RAM that stores upper and lower limit set values, alarm values, reference time for abnormality judgment, etc. 2 2 d, output port 2
It is equipped with 20 mag. Note that the control device 8 may be constructed of a discrete circuit instead of a microcomputer.

Next, the operation of this device will be explained with reference to FIGS. 5 and 6.

FIG. 5 is a flowchart regarding density control. First, the concentration sensor 6 detects conductivity (EC), which is a substitute value for fertilizer concentration.
) rate is measured and its value (EC value) is inputted via the amplifier 23 and taken in as a detected value to the CPU 22b via the AD converter 22a (step SL). CPU22
In b. This detected value is compared with upper and lower limit alarm values stored in advance in the RAM 22d to determine an abnormality (step S2), and if it is not in the abnormal area, the detected value and lower limit set value are compared in step S3. If the detected value is below the lower limit set value, the operating conditions for topdressing are determined in step S4, and if the operating conditions are met, the additional fertilizing time 'r is proportional to the deviation between the detected value and the lower limit set value. =C x deviation value (C is a constant) is calculated in step S5, and this 1'' is added to the cumulative time value of the topdressing signal in step S6.

Next, this cumulative time value is compared with the reference time (step S
7). The reference time is preliminarily set to a value that allows the fertilizer concentration of the nutrient solution to return to the normal range by -1 minute by operating the liquid fertilizer mixing bag holder 7. If the accumulated time value has not reached the reference time, an additional fertilizer signal is outputted to the liquid fertilizer mixing device 7 for the time T (step S8), and in step S9, the process waits for a certain period of time to elapse, and returns to step S1, as described above. The steps are repeated.

If there is no abnormality in the device, the liquid fertilizer mixing device 7 will operate during this repetition to perform additional fertilization, so the fertilizer concentration in the nutrient solution will eventually return to the normal range, and in step S3, the detected value will be the lower limit set value. It is detected that ``-''- has occurred. Then, the output of the top dressing signal is stopped (step SIO), and the integrated value of the top dressing signal is reset to zero (stenop S11).
. Note that even when the operating conditions are not satisfied in step S4, the procedure continues in step S1. Move to O.

On the other hand, if there is an abnormality in the equipment and topdressing cannot be performed normally, or if it is not detected that the fertilizer concentration has returned to the normal range, the cumulative time value will gradually increase and exceed the standard time, so this is the step. S7 is detected, and the procedure goes to step 3 1. 2, an alarm signal is output, the alarm device 21 is activated, and control is stopped.

Next, the operation of temperature control will be explained with reference to flowchart 1 in FIG.

First, the detected value of the liquid temperature sensor 11- is inputted via the amplifier 23, and sent to fl. The detected value is taken into the PU 22b (step S15).

The CPU 22b compares the upper and lower limit alarm values stored in the preliminary RAM 22d with the above detected value to determine an abnormality (STESOBU 816), and if 11 is not in the abnormal region, the heating operation is started in step S i 7. The conditions are determined, and if the operating conditions are satisfied, the detected value and the lower limit set value are compared in step 818. In this temperature control, dead zones are provided above and below the normal range, and if the detected value is equal to or higher than the lower limit set value, it is determined whether or not it is in the dead zone (step 822).
If it is in the dead zone, check whether it has been heating up until now (step S23), and if heating is in progress, continue heating. Further, when the heating continues or when the detection value is below the lower limit set value, the cumulative time value of the liquid warming signal is increased by a unit time (step S19).

Next, this cumulative time value is compared with the reference time (step S
20). The reference time is preliminarily set to a value that allows the temperature of the nutrient solution to sufficiently return to the normal range by the operation of the liquid temperature adjustment device 2, and if the cumulative time value or the reference time has not been reached, A liquid warming signal is output to the liquid vortex adjustment device [12 (step S2..].-), and step SF. Go back to step 5 and repeat the two steps.

If there is no abnormality in the device, the liquid temperature adjustment device ↓2 is operated and heated during this reversal l2, so the temperature of the nutrient solution will eventually return to the normal range and step S].
When it is detected in Step 8 that the detected value is equal to or higher than the lower limit set value, and furthermore that it is detected in Step S22 that it is not in the dead zone, the output of the liquid warming signal is stopped (Step S24), and the liquid warming signal is output. The integrated value of is reset to zero (step S25
). Note that the procedure also moves to step S24 when the operating conditions are not satisfied in step S22, when the dead zone is not established in step S22, or when heating was not in progress last time in step S23.

On the other hand, if there is an abnormality in the device and heating is not performed normally, or if the temperature does not return to the normal range or is not detected, the cumulative time value gradually increases and exceeds the reference time, so this is the step. is detected in S20, the procedure moves to step 82 (3), an alarm signal is output, and the alarm device 2
1 is activated and the control is also stopped.

As mentioned above, if there is an abnormality in the nitrification and additional fertilization and heating are not always carried out, or if it is not detected that the fertilizer level or liquid temperature has returned to the normal range, the standard Since it is determined that there is an abnormality after a certain period of time, the fertilizer concentration and liquid temperature will not become abnormally high due to additional fertilization and heating, and I-rubles that would adversely affect crops can be prevented.

Note that the two series of embodiments were examples of concentration control for adding fertilizer to the nutrient solution and temperature control for heating.
It can also be applied to concentration control of specific components such as H control and cooling of nutrient solutions. In addition, P-D control is generally used to control high spermatozoa, but the required precision is not so strict, and the O
The present invention can be applied to applications where N/OFF control is performed, and can also be applied to, for example, controlling water quality and water temperature in fish tanks and wastewater treatment equipment.

<Effects of the Invention> As is clear from the above explanation, the present invention determines that the concentration of the nutrient solution is abnormal when it is out of the normal range even though the concentration adjustment means has operated for a reference time, or adjusts the temperature. When the temperature of the nutrient solution is out of the normal range even though the means has been operated for a reference time, it is determined that there is an abnormality, and the control operation is stopped and an alarm is issued.

Therefore, it becomes possible to easily and quickly detect failures that could not be detected using conventional methods, making it easier to prevent negative effects on crops due to excessive fertilization, heating, cooling, etc. . Additionally, there is no need to add special sensors or the like, and the above functions can be achieved simply by changing the control procedure of the conventional device, so the reliability of the control device can be improved without increasing costs.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the basic structure of the invention, Fig. 2 is a diagram showing the structure of the invention divided into concentration control and temperature control, and Fig. 3 is a schematic diagram showing the structure of an embodiment of the invention. 4 is a block diagram of the device of the embodiment, FIGS. 5 and 6 are control flowcharts, FIG. 7 is a schematic diagram of the conventional example, and FIG. 8 is an explanation of the relationship between set values and alarm values. It is a diagram. =15-1 ・Nutritional solution tank, 2 Nutrient solution, 5 ・Sensor pot, 6
・Concentration sensor, 7 ・Liquid fertilizer mixing device, 8 Control device,
Engineering 1 ・Liquid temperature sensor, l2...Liquid temperature adjustment device, 13...
Heat exchanger.

Claims (2)

[Claims] (1) A nutrient solution concentration detection means for detecting the concentration of a nutrient solution for hydroponic cultivation; When the nutrient solution concentration detection means detects that the nutrient solution concentration is out of the normal range, the nutrient solution concentration is adjusted to within the normal range. a concentration adjusting means that operates to return the concentration to normal, a time integrating means that integrates the operating time of the concentration adjusting means, and a concentration adjusting means that determines that the nutrient solution concentration is normal when the cumulative value of the operating time of the concentration adjusting means reaches a preset reference time. A nutrient solution control device for hydroponic cultivation, comprising: determining means that determines an abnormality when it is detected that it is out of the range, stops the control operation, and issues an alarm. (2) A nutrient solution temperature detection means for detecting the temperature of the nutrient solution for hydroponic cultivation; When the nutrient solution temperature detection means detects that the nutrient solution temperature is out of the normal range, the nutrient solution temperature is adjusted to within the normal range. a temperature adjustment means that operates to return to normal temperature, a time integration means that integrates the operation time of the temperature adjustment means, and a temperature adjustment means that returns to normal when the cumulative value of the operation time of the temperature adjustment means reaches a preset reference time. A nutrient solution control device for hydroponic cultivation, comprising: determining means that determines an abnormality when it is detected that it is out of the range, stops the control operation, and issues an alarm.