阅读说明：本技术 一种木材干燥窑排潮故障报警系统 (Moisture-removing fault alarm system for wood drying kiln ) 是由 王宝坤 于 2020-07-17 设计创作，主要内容包括：本发明涉及一种木材干燥窑排潮故障报警系统,本发明的木材干燥窑烘干系统以木材干燥窑为载体,通过技术措施与干燥窑的控制柜整合在一起同时启用,系统启动后用以监测干燥窑在烘干木材作业时排潮执行器工作是否正常,排潮阀体的开、关状态是否符合指令要求。本发明主要由PLC、排潮执行器、模拟量输入单元、输入电压DC 0-10V、蜂鸣器、声光报警器、电源线组成,所述木材干燥窑排潮故障报警系统的硬件在原风机延时控制器PLC的基础上增加四路模拟量输入电压来实现；所述木材干燥窑排潮故障报警系统的软件在原风机延时控制软件的基础上,增加模拟量输入电压的检测、报警软件来实现。(The invention relates to a moisture-removing fault alarm system of a wood drying kiln, which takes the wood drying kiln as a carrier, is integrated with a control cabinet of the drying kiln by technical measures and is started at the same time, and is used for monitoring whether a moisture-removing actuator works normally when the drying kiln dries wood and whether the opening and closing states of a moisture-removing valve body meet the instruction requirements or not after the system is started. The wood drying kiln moisture removal fault alarm system mainly comprises a PLC, a moisture removal actuator, an analog input unit, an input voltage DC 0-10V, a buzzer, an audible and visual alarm and a power line, wherein four paths of analog input voltages are added to hardware of the wood drying kiln moisture removal fault alarm system on the basis of the original fan delay controller PLC; the software of the wood drying kiln moisture removal fault alarm system is realized by adding detection and alarm software of analog input voltage on the basis of the original fan delay control software.)

1. A moisture-removing fault alarm system for a wood drying kiln is characterized by comprising:

the device comprises a PLC controller and an analog input unit, wherein an EXP terminal of the PLC is connected with 4 paths of analog input units in an expanding way, and four paths of analog input voltages are increased by taking the PLC controller as a carrier;

the alarm system also comprises an audible and visual alarm and a buzzer alarm, wherein the audible and visual alarm and the buzzer alarm are respectively connected with the PLC;

when the moisture removing actuator executes a switch command, the moisture removing actuator outputs a signal to the analog quantity input unit, when the moisture removing actuator meets the following conditions, the analog quantity input unit transmits an alarm feedback signal to the PLC, and an alarm instruction is transmitted by the PLC through logical operation processing:

when the voltage difference value between any one or two of the four paths of input voltages and the other one or two or three paths of input voltages is larger than 0.3V and the duration time exceeds 200 seconds, the output terminal of the PLC immediately sends an alarm signal to the buzzer;

if the duration of the alarm signal sent by the output terminal of the PLC controller is within 30 minutes, when the voltage difference is less than 0.3V, the alarm signal is automatically stopped after being delayed for 20 seconds;

if the voltage difference is greater than 0.3V and the duration time exceeds 30 minutes, the output terminal of the PLC immediately sends an alarm signal to the audible and visual alarm, and the alarm signal can be released only when the PLC is powered off and restarted.

2. The wood drying kiln moisture removal fault alarm system as recited in claim 1, wherein the moisture removal actuator signal line is connected to VIN 1-VIN 4 terminals of the analog input unit.

3. The wood drying kiln moisture-removing fault alarm system as defined in claim 1, wherein the first input voltage U1, the second input voltage U2, the third input voltage U3 and the fourth input voltage U4 are set, when the voltage difference is determined at a certain time, the difference U12 between the first input voltage U1 and the second input voltage U2, the difference U13 between the first input voltage U1 and the third input voltage U3, and the difference U14 between the first input voltage U1 and the fourth input voltage U4 are determined in real time, if at least one of the U12, the U13 or the U14 is greater than 0.3V, and the corresponding duration time of the pressure difference greater than 0.3V exceeds 200 seconds, the output terminal of the PLC immediately sends an alarm signal to the buzzer.

4. The system of claim 3, wherein if the differential pressure value of U12 is greater than 0.3V and the differential pressure values of U13 and U14 are less than 0.3V in the 200 second period, the PLC output end sends an alarm message.

5. The system of claim 4, wherein if the difference between the first input voltage U1 and the second input voltage U2, namely the difference U12, is greater than 0.3V and the difference between the U13 or U14 is greater than 0.3V within 200 seconds, the first input voltage is reduced through the transformer, the difference U012 between the first input voltage U01 and the second input voltage U2 is determined again, the difference U013 between the first input voltage U01 and the third input voltage U3 is determined again, and the difference U014 between the first input voltage U01 and the fourth input voltage U4 is determined again.

6. The wood drying kiln moisture removal fault alarm system of claim 5, wherein reducing the first input voltage through the transformer is:

U01＝U1 x U12/U1 x0.8。

7. the wood drying kiln moisture discharge failure alarm system of claim 5,

during judgment, if the differential pressure values of the U012 and the U014 are all larger than 0.3V, and the differential pressure values of the U013 and the U014 are always smaller than 0.3V, the output end of the PLC controller sends alarm information; if the differential pressure values of the U012 and the U014 are all greater than 0.3V, and the differential pressure values of the U013 and the U014 are greater than 0.3V, the first path of input voltage is increased by the transformer as follows:

U01＝U1 x(1+U12/U1)。

8. the system of claim 7, wherein the difference U0012 between the first input voltage U001 and the second input voltage U2, the difference U0013 between the first input voltage U001 and the third input voltage U3, and the difference U0014 between the first input voltage U001 and the fourth input voltage U4 are re-determined, and if the difference between U0012 and U0014 is less than 0.3V, and the difference between U0013 and U0014 is always less than 0.3V, the output end of the PLC controller sends an alarm message.

9. The system of claim 5, wherein if the differential pressure values of U12, U13 and U14 are all greater than 0.3V, 0.3V and 0.3V respectively within the 200 second period, the PLC output end sends alarm information;

if the differential pressure values of the U12 and the U13 are all greater than 0.3V and the differential pressure value of the U14 is greater than 0.3V in the 200 second period, the fourth input voltage is reduced by the transformer as follows:

U40＝U4 x U12+U13/(2xU1)x0.8,

re-determining a difference value U120 between the first path of input voltage U10 and the second path of input voltage U02, a difference value U130 between the first path of input voltage U10 and the third path of input voltage U30, and a difference value U140 between the first path of input circuit U10 and the fourth path of input voltage U40, wherein if the differential pressure values of U120 are all greater than 0.3V, the differential pressure values of U130 are all greater than 0.3V, and the differential pressure value with U140 is always less than 0.3V, the output end of the PLC sends alarm information.

10. The wood drying kiln moisture discharge failure alarm system of claim 9, wherein when the voltage difference is less than 0.3V, the duration is 20 seconds, and in the process, if the difference between the U12 pressure value and the U13 pressure value is greater than 0.3V and the difference between the U14 pressure value is less than 0.3V in the previous 200 seconds, the alarm signal is automatically stopped after being delayed for 20 seconds;

if the voltage difference value of the U12 is greater than 0.3V and the voltage difference value of the U13 or the U14 is greater than 0.3V in the previous 200 seconds, when the alarm signal is delayed to 20 seconds, the first path of input voltage is reduced through the transformer as follows:

U01＝U1 x U12/U1 x0.8,

and re-determining a difference value U012 between the first input voltage U01 and the second input voltage U2, a difference value U013 between the first input voltage U01 and the third input voltage U3, and a difference value U014 between the first input circuit U01 and the fourth input voltage U4, and stopping alarming if the voltage difference value U012 is less than 0.3V and the voltage difference value between U013 and U014 is greater than 0.3V.

Technical Field

The invention relates to the technical field of wood drying kilns, in particular to a moisture-removing fault alarm system of a wood drying kiln.

Background

The wood drying kiln is a professional drying device applied to deep processing of wood drying, and when wood drying operation is carried out, a drying system controller transmits a signal to a moisture removal executor through a PLC (programmable logic controller) according to the change condition of the balance moisture content in the kiln. At this moment, according to the prior art, if the moisture removal actuator fails, the moisture removal valve cannot be opened or closed tightly, and the drying quality, the drying speed and the drying cost of the wood are directly influenced. The quality influences are uneven drying, deformation cracking, mildewing and blue-turning; the influence on the speed is that the drying period is prolonged and the production efficiency is reduced; the influence on the drying cost is due to the energy loss caused by the heat outflow to the kiln and the longer cycle time, resulting in a large increase in the drying cost.

In conclusion, the moisture-removing fault alarm system for the wood drying kiln is an effective measure related to the improvement of wood deep processing efficiency, cost saving and quality improvement. At present, the moisture-removing fault alarm system of the wood drying kiln applied to the field belongs to the first case at home, the technology is advanced, the field is expanded widely, and the development prospect is very long-lasting.

Disclosure of Invention

Therefore, the invention provides a moisture removal fault alarm system for a wood drying kiln, which is used for overcoming the problems in the prior art.

In order to achieve the above object, the present invention provides a moisture-removing malfunction alarm system for a wood drying kiln, comprising: the device comprises a PLC controller and an analog input unit, wherein an EXP terminal of the PLC is connected with 4 paths of analog input units in an expanding way, and four paths of analog input voltages are increased by taking the PLC controller as a carrier;

the alarm system also comprises an audible and visual alarm and a buzzer alarm, wherein the audible and visual alarm and the buzzer alarm are respectively connected with the PLC;

when the moisture removing actuator executes a switch command, the moisture removing actuator outputs a signal to the analog quantity input unit, when the moisture removing actuator meets the following conditions, the analog quantity input unit transmits an alarm feedback signal to the PLC, and an alarm instruction is transmitted by the PLC through logical operation processing:

when the voltage difference value between any one or two of the four paths of input voltages and the other one or two or three paths of input voltages is larger than 0.3V and the duration time exceeds 200 seconds, the output terminal of the PLC immediately sends an alarm signal to the buzzer;

if the duration of the alarm signal sent by the output terminal of the PLC controller is within 30 minutes, when the voltage difference is less than 0.3V, the alarm signal is automatically stopped after being delayed for 20 seconds;

if the voltage difference is greater than 0.3V and the duration time exceeds 30 minutes, the output terminal of the PLC immediately sends an alarm signal to the audible and visual alarm, and the alarm signal can be released only when the PLC is powered off and restarted.

Furthermore, the signal line of the moisture removing actuator is connected to VIN 1-VIN 4 terminals of the analog input unit.

Further, a first path of input voltage U1, a second path of input voltage U2, a third path of input voltage U3 and a fourth path of input voltage U4 are set, when a voltage difference value is judged at a certain moment, firstly, a difference value U12 between the first path of input voltage U1 and the second path of input voltage U2, a difference value U13 between the first path of input voltage U1 and the third path of input voltage U3 and a difference value U14 between the first path of input circuit U1 and the fourth path of input voltage U4 are determined in real time, and if at least one of the U12, the U13 or the U14 is greater than 0.3V and the duration time of the corresponding pressure difference value greater than 0.3V exceeds 200 seconds, an alarm signal is immediately sent to a buzzer by the PLC output terminal of the fan delay controller.

Further, if the differential pressure value of U12 is greater than 0.3V and the differential pressure values of U13 and U14 are less than 0.3V in the 200 second time, the output end of the PLC sends alarm information.

Further, if the voltage difference value U12 between the first input voltage U1 and the second input voltage U2 is greater than 0.3V and the voltage difference value U13 or U14 is greater than 0.3V within 200 seconds, the first input voltage is reduced by the transformer, the difference value U012 between the first input voltage U01 and the second input voltage U2, the difference value U013 between the first input voltage U01 and the third input voltage U3, and the difference value U014 between the first input circuit U01 and the fourth input voltage U4 are re-determined.

Further, reducing the first path of input voltage by the transformer is as follows:

U01＝U1 x U12/U1 x0.8。

further, during judgment, if the differential pressure values of the U012 and the U013 are all greater than 0.3V and the differential pressure values of the U014 and the U013 are always less than 0.3V, the output end of the PLC controller sends alarm information; if the differential pressure values of the U012 and the U014 are all greater than 0.3V, and the differential pressure values of the U013 and the U014 are greater than 0.3V, the first path of input voltage is increased by the transformer as follows:

U01＝U1 x(1+U12/U1)。

further, a difference value U0012 between the first path of input voltage U001 and the second path of input voltage U2, a difference value U0013 between the first path of input voltage U001 and the third path of input voltage U3, and a difference value U0014 between the first path of input circuit U001 and the fourth path of input voltage U4 are re-determined, and if a voltage difference value of U0012 is smaller than 0.3V and a voltage difference value of U0013 and U0014 is always smaller than 0.3V at this time, an alarm message is sent by the output end of the PLC.

Further, if the differential pressure values of U12, U13 and U14 are all greater than 0.3V and less than 0.3V within the 200 second time, the output end of the PLC sends alarm information;

if the differential pressure values of the U12 and the U13 are all greater than 0.3V and the differential pressure value of the U14 is greater than 0.3V in the 200 second period, the fourth input voltage is reduced by the transformer as follows:

U40＝U4 x U12+U13/(2xU1)x0.8,

re-determining a difference value U120 between the first path of input voltage U10 and the second path of input voltage U02, a difference value U130 between the first path of input voltage U10 and the third path of input voltage U30, and a difference value U140 between the first path of input circuit U10 and the fourth path of input voltage U40, wherein if the differential pressure values of U120 are all greater than 0.3V, the differential pressure values of U130 are all greater than 0.3V, and the differential pressure value with U140 is always less than 0.3V, the output end of the PLC sends alarm information.

Further, when the voltage difference value is less than 0.3V, the duration is 20 seconds, and in the process, if the voltage difference value of U12 is greater than 0.3V and the voltage difference values of U13 and U14 are less than 0.3V in the previous 200 seconds, the alarm signal is automatically stopped after being delayed for 20 seconds;

if the voltage difference value of the U12 is greater than 0.3V and the voltage difference value of the U13 or the U14 is greater than 0.3V in the previous 200 seconds, when the alarm signal is delayed to 20 seconds, the first path of input voltage is reduced through the transformer as follows:

U01＝U1 x U12/U1 x0.8,

and re-determining a difference value U012 between the first input voltage U01 and the second input voltage U2, a difference value U013 between the first input voltage U01 and the third input voltage U3, and a difference value U014 between the first input circuit U01 and the fourth input voltage U4, and stopping alarming if the voltage difference value U012 is less than 0.3V and the voltage difference value between U013 and U014 is greater than 0.3V.

Compared with the prior art, the wood drying kiln drying system has the advantages that the wood drying kiln is used as a carrier, the wood drying kiln drying system is integrated with a control cabinet of the drying kiln and started at the same time through technical measures, and the system is used for monitoring whether the moisture removal actuator works normally when the drying kiln dries wood, and whether the opening and closing states of the moisture removal valve body meet the instruction requirements or not after being started. The invention mainly comprises a PLC, a moisture removal actuator, an analog input unit, an input voltage DC 0-10V, a buzzer, an audible and visual alarm and a power line, wherein 4 paths of analog input voltages are added to the hardware of the wood drying kiln moisture removal fault alarm system on the basis of an original fan delay controller PLC (OMRON SYSMAC CP1E) to realize the purpose; the software of the wood drying kiln moisture removal fault alarm system is realized by adding detection and alarm software of analog input voltage on the basis of the original fan delay control software.

Particularly, when the voltage difference value of U12 is greater than 0.3V and the voltage difference value of U13 or U14 is greater than 0.3V, a detection error condition may exist in four paths of voltages, the path of voltage with the difference value is subjected to voltage boosting compensation and voltage reducing compensation, the comparison result of the difference value of the path of voltage and other path of voltage and 0.3V is redetermined, and whether the output end of the PLC sends alarm information is determined by judging the comparison result.

Particularly, when the alarm is stopped, the voltage of the path with the difference is subjected to boost compensation and buck compensation, the comparison result of the difference between the voltage of the path and the voltage of other paths and 0.3V is determined again, and whether the output end of the PLC has an error or not is determined and whether the alarm is stopped or not is determined by judging the comparison result.

Drawings

FIG. 1 is a functional block diagram of an environment-friendly wood drying kiln moisture removal fault alarm system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a moisture removal fault alarm circuit according to an embodiment of the present invention;

fig. 3 is a schematic view of a PLC instruction program for warning of moisture discharge failure according to an embodiment of the present invention.

Detailed Description

In order that the objects and advantages of the invention will be more clearly understood, the invention is further described below with reference to examples; it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and do not limit the scope of the present invention.

Furthermore, it should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Fig. 1 is a schematic structural diagram of an environment-friendly wood drying kiln moisture-removing fault alarm system according to an embodiment of the present invention; the alarm system of the embodiment comprises a PLC controller and an analog input unit, wherein an EXP terminal of the PLC is connected with 4 paths of analog input units in an extended mode; the alarm device also comprises an audible and visual alarm and a buzzer alarm, wherein the audible and visual alarm and the buzzer alarm are respectively connected with the PLC. When the feedback voltage is wrong, the analog quantity input unit transmits sampling information to the PLC, the PLC carries out logical operation according to the ladder diagram and outputs a voltage signal to one terminal of the PLC to a buzzer (hereinafter referred to as FM) and one terminal of the PLC to an audible and visual alarm (hereinafter referred to as BJ).

And the COM end of the PLC, the buzzer and one end of the audible and visual alarm are connected with the N line.

The device also comprises a transformer, wherein the transformer is connected with the moisture removal actuator and supplies power to the moisture removal actuator, and the transformer is also connected with the analog quantity input unit and supplies power to the analog quantity input unit. The input end of the transformer is connected with 220V voltage, the output voltage is 24V alternating current under the conventional condition, and the transformer is responsible for supplying power to the moisture removal actuator PC. The signal line of the moisture removing actuator is connected to VIN1 terminals-VIN 4 terminals of the analog quantity input unit; when the moisture removing actuator executes a switch command, the moisture removing actuator outputs a signal to the analog quantity input unit, when the moisture removing actuator meets the following conditions, the analog quantity input unit transmits an alarm feedback signal to the PLC, and an alarm instruction is transmitted by the PLC through logical operation processing:

the method is realized by adding four paths of analog quantity input voltages by taking a PLC (programmable logic controller) as a carrier, and when the voltage difference value of any one or two paths of voltages and the voltage difference value of the other one or two paths or three paths of voltages in the four paths of input voltages is more than 0.3V and the duration time exceeds 200 seconds, an output terminal of the PLC of the fan delay controller immediately sends an alarm signal to a buzzer. In this embodiment, the drying of timber drying kiln is realized through the fan, and the moisture removal executor control fan action to carry out the drying to timber under the control action of predetermineeing, this is conventional technique, and no longer give unnecessary details.

In this embodiment, a first input voltage U1, a second input voltage U2, a third input voltage U3, and a fourth input voltage U4 are set, and when a voltage difference is determined at a certain time, a difference U12 between a first input voltage U1 and a second input voltage U2, a difference U13 between a first input voltage U1 and a third input voltage U3, and a difference U14 between a first input circuit U1 and a fourth input voltage U4 are determined in real time, if at least one of the voltage differences U12, U13, and U14 is greater than 0.3V, and a duration time of the corresponding voltage difference greater than 0.3V exceeds 200 seconds, the output terminal of the PLC controller immediately sends an alarm signal to the buzzer.

If the pressure difference value of U12 is greater than 0.3V and the pressure difference values of U13 and U14 are less than 0.3V in the 200 second time, the output end of the PLC sends alarm information;

if the voltage difference value of the U12 is greater than 0.3V and the voltage difference value of the U13 or U14 is greater than 0.3V in the 200 second period, the first input voltage is reduced by the transformer as follows:

U01＝U1 x U12/U1 x0.8,

re-determining a difference value U012 between a first path of input voltage U01 and a second path of input voltage U2, a difference value U013 between a first path of input voltage U01 and a third path of input voltage U3, and a difference value U014 between a first path of input circuit U01 and a fourth path of input voltage U4, wherein if the differential pressure values of U012 are all greater than 0.3V and the differential pressure values of U013 and U014 are always less than 0.3V, the output end of the PLC sends alarm information; if the differential pressure values of the U012 and the U014 are all greater than 0.3V, and the differential pressure values of the U013 and the U014 are greater than 0.3V, the first path of input voltage is increased by the transformer as follows:

U01＝U1 x(1+U12/U1),

and re-determining a difference value U0012 between the first path of input voltage U001 and the second path of input voltage U2, a difference value U0013 between the first path of input voltage U001 and the third path of input voltage U3, and a difference value U0014 between the first path of input circuit U001 and the fourth path of input voltage U4, wherein if the voltage difference value of U0012 is smaller than 0.3V and the voltage difference value of U0013 and U0014 is always smaller than 0.3V at the moment, the output end of the PLC sends alarm information.

Therefore, in the embodiment of the present invention, when it is determined that the voltage difference values of U12 are all greater than 0.3V, and the voltage difference values of U13 or U14 are greater than 0.3V, a detection error condition may exist in the four paths of voltages, the embodiment performs voltage boosting compensation and voltage dropping compensation on the path of voltage in which the difference value exists, re-determines the comparison result between the difference value of the path of voltage and the other path of voltage and 0.3V, and determines whether the output end of the PLC controller sends alarm information by determining the comparison result.

If the pressure difference values of U12, U13 and U14 are all greater than 0.3V, and less than 0.3V within the 200 second time, the output end of the PLC sends alarm information;

if the differential pressure values of the U12 and the U13 are all greater than 0.3V and the differential pressure value of the U14 is greater than 0.3V in the 200 second period, the fourth input voltage is reduced by the transformer as follows:

U40＝U4 x U12+U13/(2xU1)x0.8,

re-determining a difference value U120 between a first path of input voltage U10 and a second path of input voltage U02, a difference value U130 between a first path of input voltage U10 and a third path of input voltage U30, and a difference value U140 between a first path of input circuit U10 and a fourth path of input voltage U40, wherein if the differential pressure values of U120 are all greater than 0.3V, the differential pressure values of U130 are all greater than 0.3V, and the differential pressure values of U140 are always less than 0.3V, an output end of the PLC sends alarm information; if the differential pressure values of the U120 and the U130 are greater than 0.3V, and the differential pressure value of the U140 is greater than 0.3V, then the step-up of the fourth input voltage by the transformer is:

U400＝U400 x(1+U12/U1+U13/U1),

and re-determining a difference value U01200 of the first path of input voltage U100 and the second path of input voltage U200, a difference value U1300 of the first path of input voltage U100 and the third path of input voltage U300, and a difference value U1400 of the first path of input circuit U100 and the fourth path of input voltage U400, wherein if the pressure difference value of U1200 is less than 0.3V, the pressure difference value of U1300 is less than 0.3V, and the pressure difference value of U1400 is always less than 0.3V, the output end of the PLC sends alarm information.

If the duration of the alarm signal sent by the output terminal of the PLC controller is within 30 minutes, and if the voltage difference is less than 0.3V, the alarm signal is automatically stopped after 20 seconds of delay.

In this embodiment, when the voltage difference is less than 0.3V, the duration is 20 seconds, and in this process, if the voltage difference of U12 is greater than 0.3V and the voltage difference of U13 and U14 is less than 0.3V in the previous 200 seconds, the alarm signal is automatically stopped after being delayed for 20 seconds.

If the pressure difference value of U12 is greater than 0.3V and the pressure difference value of U13 or U14 is greater than 0.3V in the previous 200 seconds, when the alarm signal is delayed to 20 seconds,

the first path of input voltage is reduced through a transformer:

U01＝U1 x U12/U1 x0.8,

re-determining a difference value U012 between a first input voltage U01 and a second input voltage U2, a difference value U013 between a first input voltage U01 and a third input voltage U3, and a difference value U014 between a first input circuit U01 and a fourth input voltage U4, and stopping alarming if the differential value U012 is less than 0.3V and the differential value U013 and U014 is greater than 0.3V; if the differential pressure value of the U012 is greater than 0.3V, and the differential pressure value of the U013 and the U014 is less than 0.3V, the first input voltage is increased by the transformer as follows:

U01＝U1 x(1+U12/U1),

and re-determining a difference value U0012 between the first path of input voltage U001 and the second path of input voltage U2, a difference value U0013 between the first path of input voltage U001 and the third path of input voltage U3, and a difference value U0014 between the first path of input circuit U001 and the fourth path of input voltage U4, and stopping alarming if the voltage difference value of U0012 is less than 0.3V and the voltage difference value of U0013 and U0014 is always greater than 0.3V.

Therefore, when the alarm is stopped, the embodiment of the invention performs the voltage boosting compensation and the voltage reducing compensation on the path of voltage with the difference value, re-determines the comparison result between the difference value of the path of voltage and the other path of voltage and 0.3V, determines whether the output end of the PLC has an error or not by judging the comparison result, and determines whether the alarm is stopped or not.

If the voltage difference is greater than 0.3V and the duration time exceeds 30 minutes, the output terminal of the PLC immediately sends an alarm signal to the audible and visual alarm, and the alarm signal can be released only when the PLC is powered off and restarted. In the embodiment, when the voltage difference value is determined to be greater than 0.3V and continues to exceed 200 seconds, and the voltage difference value continues to exceed 30 minutes, an audible and visual alarm is sent.

If the output terminal sends an alarm signal, a buzzer arranged on the control cabinet sounds for a long time; when the output terminal sends an alarm signal, the audible and visual alarm arranged in the master control room gives an alarm.

Referring to fig. 2 and 3, in the present embodiment, a COM terminal of a PLC controller OMRON SYSMAC CP1E (hereinafter referred to as PLC) is connected to a 220V voltage, an EXP terminal of the PLC is connected to 4 analog input units (hereinafter referred to as MK) in an extended manner, when a feedback voltage is incorrect, the analog input units transmit sampling information to the PLC, the PLC performs logical operation according to a ladder diagram to output a voltage signal to a 02 terminal on the lower right of the PLC to a buzzer (hereinafter referred to as FM), and outputs a voltage signal to an 03 terminal on the lower right of the PLC to an audible and visual alarm (hereinafter referred to as BJ);

2. the COM end of MK, the end of BJ and the end of FM are connected with N;

3. the input end of a transformer (hereinafter, abbreviated as BY) is connected with 220V voltage, the output voltage is 24V alternating current, and the BY is responsible for supplying power to a moisture removal actuator (hereinafter, abbreviated as PC);

4. a signal wire of the PC is connected with VIN1 terminals to VIN4 terminals of the MK;

5. when the PC executes the switch command, the signal is output to the MK, and when the following conditions are met, the MK transmits the alarm feedback signal to the PLC, and the PLC carries out logical operation processing to transmit the alarm instruction, as described above.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention; various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.