KR20180123334A - Current monitoring board and control method thereof - Google Patents

Abstract

A current monitoring board and a control method thereof are disclosed. The current monitoring board of the present invention includes an in-connector connected to power lines, a fuse having one end electrically connected to one of the power lines connected to the in-connector, a relay electrically connected to the other end of the fuse, a current transformer (CT) electrically connected to the relay, an solid state relay (SSR) electrically connected to the CT, an out-connector connected to the output line of the SSR and another line of the in-connector, and a current monitoring part for monitoring the state of an electric energy signal induced by the CT and the state of the SSR control I/O control signal in real time. So, it is possible to prevent the failure of a load, and to solve the problem by quick action, by detecting the abnormal current on the current monitoring board and shutting it off.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current monitoring board,

[0001] The present invention relates to a current monitoring board, and more particularly, to a current monitoring board that monitors an AC current conversion signal and an SSR I / O signal in real time to notify an alarm signal and a replacement time of a fuse, To a current monitoring board and a control method thereof.

In electronic devices, relays switch voltage / current. Solid-state relays (SSRs) are solid state relays (SSRs) that are switched in a resin-molded state using a semiconductor device that does not have a mechanical contact structure, while a magnet relay operates by a mechanical contact- Electronic switch.

In particular, SSR consists of photocoupler, zero-cross circuit, triac, rectifier circuit, and protection circuit. It suppresses input noise, overcurrent and inrush current during operation and enables high-speed switching to a contactless point.

However, the SSR may also break down due to surge voltage or overcurrent, resulting in failure. If the load can not be shut off due to this, the device will be destroyed or the entire circuit in which SSR is used will cause a serious problem.

Conventionally, in order to solve such a problem, when an overcurrent occurs in the SSR, a trip is made or a fuse is provided to protect the SSR from an overcurrent. However, these methods are problematic in that an abnormal current is cut off when an over current and a short circuit are generated, but it takes a long time to return to a normal state after shutting off.

In addition, when an abnormality occurs, the interruption of the voltage is delayed, so that the motor or the heater is damaged and the state becomes unusable.

In particular, when a voltage is supplied from a power source that is always supplied with power, such as a battery, it is impossible to reset the input voltage after the over current is cut off.

In addition, a load such as a motor or a heater that uses electricity as power or illumination requires a relatively high voltage in the initial operation so as to maximize the efficiency, and a voltage in the range of the efficiency of the load or the input voltage And the power is controlled to be used efficiently. However, when the high voltage or the low voltage is inputted in the initial operation, the efficiency of the device is lowered and the life of the load is shortened.

In order to solve the above problems, a current control device has been disclosed. In the conventional current control device, a plurality of trigger signals are generated in accordance with an input voltage of a current coil controlling a current supplied to a load, To the gates of the plurality of switching elements for switching the winding of the magnetic flux chain choke coil connected to the winding to control the voltage supplied to the load.

However, since the above-described current control device controls the voltage supplied to the load by using the voltage supplied to the current coil, a phase difference occurs between the output voltage of the current coil and the input voltage, There is a problem that the switching element is broken or an overvoltage is supplied to the load.

In addition, since NFB (No Fuse Breaker) is used to cut off the overcurrent to the overload and short circuit of electricity, it is not possible to set the required current value by arbitrarily setting the usable load. That is, Can not be suppressed.

In addition, since the operation for maintaining the constant voltage by the fluctuation of the load, the maintaining of the output voltage constant voltage due to the voltage fluctuation of the input side, the initial voltage starting by the initial operating characteristic, the setting time and the constant voltage maintenance in accordance with the set voltage occur quickly and frequently, In order to adjust the level of the voltage, the elements of the switching means are frequently turned on / off in the zero crossing according to the trigger control signal at the moment when the input / output voltage is synchronized. At this time, since the operation speed is too fast, There is a problem that two elements of the switching means coupled to the magnetic flux chain choke coil to be controlled are simultaneously operated, that is, an overcurrent due to an instantaneous short-circuit occurs and the elements of the switching means are destroyed.

KR Patent Publication No. 10-2016-0076939 (Jul.

In order to solve such a problem, the present invention aims to provide a current monitoring board and a control method thereof, which can control and control signals transmitted from a controller of a current monitoring board for controlling a motor or a heater to an MCU.

Another object of the present invention is to provide a current monitoring board having a fuse, a relay, and a current monitor, and a control method thereof, which can adjust the sensitivity of the CT.

Another object of the present invention is to provide a current monitoring board and a control method thereof that can notify an administrator of an abnormal current when an abnormal current is generated, and can quickly recover it.

In the present invention, only one communication between the PLC and the CT BOARD is possible. In order to solve the problem that the communication between the CT BOARD and the conventional communication can not be performed due to the communication between the CT BOARD and the PLC, Up to 8 CT BOARDs can be used in conjunction with each other. Each of the 8 CT BOARDs can be used in combination with each (4, 8, 10, and 12 CH) CT BOARD, Another object of the present invention is to provide a current monitoring board and a control method thereof.

      It is another object of the present invention to provide a current monitoring board and a control method thereof, which can directly block a power input to a heater or a motor by adding a relay in a CT BOARD.

It is still another object of the present invention to provide a current monitoring board and a control method thereof, in which an electronic CT is used and a relay is formed in the next stage of fuse for protection of a relay circuit due to an overcurrent.

Further, the present invention can display the current value read by the CT on the HMI to monitor the current value flowing through the HMI. Another object of the present invention is to quickly detect an abnormality and prevent an unexpected accident.

According to an aspect of the present invention, there is provided a current monitoring board for protecting a circuit by disconnecting a fuse during an overcurrent, the apparatus comprising: an in connector to which a power line is connected; and a power line A CT (current transformer) electrically connected to the relay, a solid state relay (SSR) electrically connected to the CT, an output line of the SSR, and an output line of the SSR, the fuse being electrically connected to one end of the fuse, And an electric current monitoring unit for monitoring the state of the electric energy signal induced by the CT and the I / O control signal for controlling the SSR in real time and notifying an alarm signal when an abnormality occurs Can be achieved.

In addition, the current monitoring unit includes a control unit for outputting the I / O control signal for controlling the SSR, and an I / O signal for SSR control of the control unit, receiving the electric energy induced by the CT as an AC current conversion signal, And an MCU (Microprocessor) for determining whether or not a star AC current conversion signal is input and determining whether power is supplied or not when the non-communication SSR is turned on. The MCU transmits an alarm signal of the corresponding SSR to the controller The controller turns on an LED indicating the position of the fuse corresponding to the transmitted alarm signal and notifies the replacement of the fuse and simultaneously transmits a control signal for shutting off the power of the corresponding channel to the relay.

The MCU includes a communication unit for performing RS485 or RS422 communication with an external PLC, a first rotary switch for selecting a current value of a current transformer according to the size of a load connected to the out connector, a solid state relay And a second rotary switch for setting the timing sensitivity of the second rotary switch, and a second rotary switch for converting the electric energy induced in the CT into a voltage via a current to voltage converter circuit, To an AC current conversion signal converted into an AC current conversion signal.

Meanwhile, a method of controlling a current monitoring board that protects a circuit by disconnecting a fuse during an overcurrent according to an embodiment of the present invention includes: (a) selecting a current value of a current transformer as a rotary switch according to a size of a load; (B) setting a timing sensitivity of SSR (Solid State Relay) using another rotary switch, (c) connecting one of the power lines to the direct load, (CT) and the SSR are sequentially connected to the load, and (d) the electric energy induced in the CT is converted into an AC current (E) inputting the SSR I / O control signal of the control unit for controlling the voltage and current flowing to the load to the MCU; and (f) AC current conversion signal and the SSR I / O signal is monitored in real time to determine whether or not an AC current conversion signal for each SSR is inputted and it is determined whether power is supplied or non-powered SSR is energized. When an abnormality occurs, an alarm signal of the SSR is transmitted to the controller, A step of controlling the LED to turn on the LED indicating the position of the fuse corresponding to the transmitted alarm signal to inform the replacement of the fuse and to turn off the power of the corresponding channel.

The step (d) includes the steps of (d-1) inputting one line of the power supply line to the load to the AC input of the current monitoring board, and (d-2) (D-3) an AC current conversion signal obtained by converting the voltage converted in the step (d-2) from the AD converter to a digital value is input to the MCU through a current to voltage converter circuit Step < / RTI >

And (g) providing at least two current monitoring boards and each current monitoring board communicating with each other or the PLC via RS485 or RS422 communication, (h) transmitting alarm information generated at the step (f) To the terminal, it is possible to communicate between the CT boards or the RS485 or RS422 with the PLC.

Therefore, according to the current monitoring board and the control method thereof according to the present invention, when an abnormal current is generated in the current monitoring board, the current monitoring board detects and blocks the abnormal current, thereby preventing a failure of the current monitoring board and the load. Can be solved.

In addition, the present invention rapidly detects when an overcurrent flows due to a load overcurrent or a load short-circuit by controlling the sensitivity of the CT and adjusting the timing of the SSR, instantaneously shutting off the output voltage and replacing the shorted fuse, There is an effect that can be performed.

According to the current monitoring board and the control method of the present invention, an alarm is generated and an abnormal signal is notified to a manager terminal at a remote place, thereby quickly resolving the abnormal state and minimizing the damage to the motor or the heater .

In addition, according to the current monitoring board and the control method thereof according to the present invention, when an error or an alarm occurs after the power is turned on, the power of each channel can be individually cut off, and the stability is high. Added functionality to increase safety.

      According to the current monitoring board of the present invention and the control method thereof, the conventional CT BOARD is not capable of shutting off the power when an error or alarm occurs, but only the alarm is loaded on the PLC or the host controller. However, So that an accident or an accident can be prevented by directly shutting off the power supply when an error or an alarm occurs.

According to the current monitoring board and the control method of the present invention, it is possible to improve accuracy by using an electronic CT having high precision as a result of comparison between the conventional through CT and the electronic CT and to protect the relay circuit due to the overcurrent The relay is protected by disconnection of the fuse when the overcurrent flows.

1 is a main configuration diagram of a current monitoring board according to an embodiment of the present invention,
2 is a detailed configuration diagram of the current monitoring board of the present invention,
3 is a main configuration diagram of a terminal of the present invention,
And
4 is a flowchart for explaining the operation of the current monitoring board of the present invention.

It is to be understood that the words or words used in the present specification and claims are not to be construed in a conventional or dictionary sense and that the inventor can properly define the concept of a term in order to describe its invention in the best possible way And should be construed in light of the meanings and concepts consistent with the technical idea of the present invention.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise. It should be noted that the terms such as " part, "" module, " .

It is to be understood that the term "and / or" throughout the specification includes all possible combinations from one or more related items. For example, the meaning of "first item, second item and / or third item" may be presented from two or more of the first, second or third items as well as the first, second or third item It means a combination of all the items that can be.

Identification codes (e.g., a, b, c, ...) in each step throughout the specification are used for convenience of description, and the identification codes do not limit the order of each step, Unless the context clearly states a particular order, it may take place differently from the stated order. That is, each step may occur in the same order as described, may be performed substantially concurrently, or may be performed in reverse order.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a main configuration diagram of a current monitoring board according to an embodiment of the present invention. As shown in FIG. 1, in order to protect a circuit by disconnecting a fuse during an overcurrent, The power supply line of the power supply 200 is input to detect an abnormal state and output the detected abnormal state to the load 300.

In the present invention, the current monitoring board 100 enables communication between the remaining monitoring boards or the terminal 400 operating as a PLC through RS485 or RS422 communication.

That is, it is possible to use up to eight current monitoring boards 100 by using RS485 or RS422 communication.

Hereinafter, RS485 or RS422 communication will be briefly described.

Typically, an asynchronous communications controller is commonly referred to as a UART (Universal Asynchronous Receiver / Transmitter). The signal from the UART usually has a TTL signal level, which is weak to noise and has a limited communication range. An interface IC that receives these TTL signals and allows them to be strong and far from noise is called a LINE DRIVER / RECEIVER, and RS422 and RS485 are typical ones.

The difference between RS422 and RS485 is that the maximum driver and receiver is 1:10 for RS422, and 32:33 for RS485, and RS422 is Full Duplex and RS485 is half Duplex.

In the drawing, at least one current monitoring board 100 and a current monitoring board 100n are shown. Up to 8 current monitoring boards can be used by mixing 4, 8, 10 and 12 current monitoring boards for each type.

In addition, eight current monitoring boards can communicate with the terminal 400 by designating respective communication station numbers.

For example, the communication station numbers of the eight current monitoring boards can be used as "01 to 08" to be distinguished from each other.

Conventional communication was not able to communicate with each other due to no communication between current monitoring boards.

In other words, in the past, only the communication with the PLC and the current monitoring board 1EA was possible, but in the present invention, it is possible to use the RS485 or RS422 communication with a maximum of eight current monitoring boards 100 to use.

A general current monitoring board monitors the flow of current in a device using a current such as a heater or a motor, and performs a function of giving a warning signal to the main controller when an abnormal operation is detected.

Therefore, the load 300 will be described as a heater or a motor in the following description.

Here, the abnormal operation means a case where the current is energized when the current should be energized or when the energization should not occur.

In addition, the current monitoring board 100 of the present invention transmits an abnormal state to the administrator terminal 400 in case of an abnormality, so that the current monitoring board 100 can be quickly recovered.

To this end, the current monitoring board 100 includes a fuse 120 electrically connected to one end of a line of a power supply line connected to the in connector 150 and a power supply line, a fuse 120, A CT (current transformer) 130 electrically connected to the relay 170 and a CT 130 electrically connected to the other end of the CTR 130, and a solid state A current monitor 110 for monitoring the status of the electric energy signal induced by the relay 140 and the CT 130 and the status of the I / O control signal for controlling the SSR to inform the alarm signal when an abnormality occurs, And an out connector 160 to which the other power line of the line connector 150 is connected.

The relay 170 is added to the current monitoring board and operates to shut off the power input to the heater or the motor.

In the present invention, by using the relay 170, when an error or an alarm occurs after the power is turned on, a function of individually intercepting the power of each channel is added to enhance safety.

The relay is generally used with a capacity of 5A and a high capacity of 10A.

Accordingly, in the conventional current board, when an error or an alarm occurs, there is no power cutoff capability, and only an alarm is displayed on the PLC or the terminal 400. However, the present invention is applicable to a power- Because it uses relays, it can prevent accident by preventing power failure by directly turning off the power when an error or alarm occurs.

Also, the position of the relay 170 in the present invention is configured at the next stage of the fuse 120 to protect the circuit in order to protect the circuit due to the overcurrent.

Current transformer (CT) means a current transformer for a meter. Like the principle of PT, PT is for viewing or using voltage, and CT is configured for viewing or using current.

That is, it is used as a power source of the current meter of the switchboard, the current coil of the power meter, and the power source of the trip coil of the overcurrent relay, in order to lower the high current of the high voltage circuit to a small current.

In addition, if the secondary side is opened while current flows through the primary coil of the current transformer, a high voltage is generated in the secondary terminal, causing damage or electric shock.

Because CT is also a transformer, the magnetic flux generated in the primary coil and the magnetic flux generated in the secondary coil are linked together and are no longer saturated. However, if the secondary is opened (released), the primary flux So that it becomes a permanent eddy flux and becomes saturated, and later it explodes and is damaged.

Since CT or PT accidents usually account for more than half of the power outages occurring at the water purification plant, it is necessary to pay close attention to careful observation. It is necessary to perform an overhaul if an unusual noise occurs, unlike usual, without overloading.

Further, in the present invention, the use of an electronic CT is another feature in order to increase the precision of the CT.

As a result of comparison between conventional penetrating CT and electronic CT, electronic CT is used because of its high precision.

In the present invention, the output of the CT is received and monitored by the current monitoring unit 110, and the SSR 140 is controlled, thereby preventing explosion.

SSR (Solid State Relay) 140 is a non-contact relay, a semiconductor relay, and a solid-state relay, and is formed of electronic contacts using semiconductor elements instead of mechanical contact structures.

The SSR 140 receives power from the power source 200 and is controlled by the current monitoring unit 110, and the load 300 is connected to the output of the SSR 140.

The current monitoring unit 110 monitors the state of the electric energy signal induced by the CT 130 and the I / O control signal for controlling the SSR in real time, and notifies the alarm signal when an abnormality occurs.

The current monitoring unit 110 detects an abnormal current such as an input noise, an overcurrent, and an inrush current, controls the SSR 140 to perform a reset operation of the circuit, is a semiconductor switch element including a logic circuit therein, Lt; RTI ID = 0.0 > 300 < / RTI >

In the present invention, the current monitoring unit 110 monitors the current and state of the current flowing through the CT 130, prevents the abnormal current from occurring when the abnormal current is generated, and protects the abnormal current by blocking the abnormal current flowing into the load.

To this end, the current monitoring unit 110 receives the electric energy induced by the CT 130 as an AC current conversion signal and outputs the SSR control I / O control signal to the control unit 112, O signal and receives an AC current conversion signal for each SSR 140, and determines whether the SSR 140 is energized or not.

Also, the current monitoring unit 110 monitors the state of the SSR control I / O control signal in real time, notifies the alarm signal when an error occurs, and transmits a control signal to the relay 170 to shut off the power.

The MCU 111 transmits an alarm signal of the corresponding SSR to the controller 112. The controller 112 turns on the LED 113 indicating the position of the fuse corresponding to the transmitted alarm signal, .

Therefore, the LED 113 is installed near the fuse as much as the number of the fuses so that the replacement of the fuse is informed.

The MCU 111 includes a first controller 115a configured to select a current value of the CT 130 according to the magnitude of a load connected to the out connector 160 and a second controller 115b configured to control the timing of the SSR 140 ) Sensitivity is set to the second control unit 115b.

The MCU 111 converts the electric energy induced in the CT 130 to a voltage through a current to voltage converter 116a circuit and converts the converted voltage from the AD converter 116b to a digital value An AC current conversion unit 116 for converting the converted AC current conversion signal into an AC current conversion signal and inputting the converted AC current conversion signal to the MCU 111 is connected

The AC current conversion unit 116 converts the electrical energy induced in the CT 130 to a voltage via the current voltage converter 116a and inputs the digital voltage to the ADC 116b and inputs the digital value to the MCU 111 Or the output of the current-voltage converter 116a to the A / D circuit of the MCU.

The control unit 112 is connected to the MCU 111 so as to control the SSR control I / O signal, that is, the I / O signal for determining whether the SSR is energized or not, and controls the LED 113 .

Also, the MCU 111 receives the SSR for the energizing switch of the control unit 112 for controlling the voltage and current flowing to the load 300 or the I / O signal of the relay.

The MCU monitors in real time the states of the two input signal components, the AC current conversion signal of the AC current conversion unit 116, and the control I / O signal of the control unit 112 to determine whether the current is turned on or not, And transmits an Alarm Out signal to the controller 112 when an abnormality occurs.

The LED 113 is disposed adjacent to each fuse 120 and is turned on or off under the control of the control unit 112 to inform the fuse 120 of the failure.

That is, the current monitoring unit 110 receives the voltage from the normal CT 130 and operates. The control unit 112 receives the control signal from the control unit 112 and senses the abnormal current when an abnormal current is generated from the CT 130 through the AC current conversion unit 116, The control signal is interrupted. That is, when the magnitude of the current input from the AC current conversion unit 116 suddenly increases or the amount of the input current is not constant, the I / O control signal is blocked to prevent the failure of the load 300 will be.

That is, according to the present invention, only CT is provided, and current is detected in the CT and only the signal is transmitted. However, the control unit transmits a signal to the MCU to perform proportional control.

In addition, the sensitivity of CT is adjustable from 1A to 9A by using a dial switch, and a fuse is provided to protect the circuit by disconnection during overcurrent.

In the present invention, ports connected to SSRs and PLCs, as well as in-out connectors, are used, and the communication between them is configured to use RS-485 communication.

As mentioned above, RS-485 has expanded the number of RS-482 limited devices, and it has an advantage that network of multi equipment can be created by communication method with enhanced input and output voltage parts.

This is because RS-485 is appropriate for distributing multiple current monitoring boards over the network and for managing distributed equipment.

With the use of such a communication device, the present invention can transmit the abnormality of each current monitoring board to the terminal, confirm it in the terminal, and solve the problem of the current monitoring board.

To this end, the MCU 111 further includes a communication unit 114.

Specifically, the MCU 111 can notify the terminal 400 of abnormality through the communication unit 114 when an error occurs.

When one or more current monitoring boards 100 are dispersed on a network, the MCU 111 has a unique ID that is different from other MCUs and communicates with the terminal. The terminal holder sees a unique ID when an error occurs, Can be done.

Of course, at this time, the MCU 111 has a unique ID, and if necessary, transmits the monitoring information to the terminal 400 together with the corresponding ID.

For this purpose, the terminal 400 may include a communication interface 410 for communicating with the MCU 111.

3, the terminal 400 of the present invention includes a storage unit 460 storing a unique ID and installation location of one or more current monitoring boards connected to the network in a table, And receives an alarm signal together with a unique ID through the communication interface 410, the controller 410 drives an app stored in the user app unit 450 in the terminal display unit 420, And a terminal control unit 440 for informing whether or not the mobile terminal 440 is operating.

The terminal control unit 440 executes the application stored in the user application unit 450 to receive the unique ID of the current monitoring board and notify the user of the failure.

The terminal 400 is composed of a tablet, a smartphone, a PDA, or a dedicated terminal. The terminal 400 performs wireless communication and Internet communication like a normal smartphone, and reads a unique ID from the current monitoring board to determine a failure or the like.

The user application unit 450 is configured to download and store related apps through an application store or access the server through a mobile communication network to download and install applications.

Preferably, the application may be installed through the authentication process of the server during the installation of the application (App).

That is, although the present invention can connect to a server operating as a web site and download and install an app, it is possible to use a method of uploading an application suitable for each OS to an app store regardless of whether the application is an IOS system or an Android system.

The process of downloading and installing the application (App) and the step of authentication are general, and a detailed description thereof will be omitted.

These applications can display where the current monitoring board with unique ID is located, product information, and so on.

The key input unit 430 may be configured to input data for the corresponding key using a touch screen or a keypad. The key input unit 430 may include keys necessary for controlling functions of a normal smartphone, a current monitoring board of the present invention, A specific button, and the like.

The storage unit 460 is configured to store the installation place for each unique ID and the like in a table.

The communication interface 410 is capable of transmitting and receiving data through various communication methods (web communication, wireless communication, Bluetooth, Zigbee, etc.), but in the present invention, the communication interface 410 can communicate with the current monitoring board 100 through web or wireless communication .

The terminal display unit 420 operates as a display device for displaying call related data received through the normal communication interface 410. In the present invention, the terminal display unit 420 is configured to display data received through a running app.

Through the above configuration, the terminal control unit 440 reads the unique ID of the received current monitoring board by performing the application, reads the place where the current monitoring board having the unique ID is installed, etc. from the storage unit 460, ) To display the data in the app.

Hereinafter, the operation of the current monitoring board having the above-described configuration will be described.

4 is a flowchart for explaining the operation of the current monitoring board of the present invention. In order to operate the current monitoring board of the present invention, a power line is connected to the in connector 150, To the load.

That is, one of the power lines is inputted to the AC input of the current monitoring board, the fuse 120 is connected to the CT 130, the output of the CT 130 is inputted to the SSR 140, and the SSR 140 To be connected to the load 300 through the out connector 160. [

First, the current value is selected by the rotary switch of the first control unit 115a according to the load of each channel, and the SSR timing sensitivity is selected by the rotary switch of the second control unit 115b (S110 ).

The sensitivity of the second adjustment unit 115b in step S110 is to set the sensitivity with respect to the time of notifying the alarm.

In step S111, the load 300 is connected to the out connector 160, and then the control signal I / O signal line of the controller 112 is connected to the SSR 140 irrespective of the polarity (S112).

In step S113, it is confirmed whether there is connection with the controller 112 such as a PLC, and an electrical connection with the SSR or the like is confirmed.

When the configuration and connection are completed in steps S110 to S113, the MCU 111 monitors the status of the AC current conversion signal of the AC current conversion unit 116 and the control I / O signal of the control unit 112 in real time (S114) If an abnormality occurs, the LED 113 is turned on or the power is turned off (S115).

At the same time, the MCU 111 transmits an abnormality to the PLC or the terminal 400 so that the supervisor can recognize the abnormality (S116).

If the LED is turned on in step S114, the problem can be solved by replacing the fuse.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art.

100: current monitoring board 110: current monitoring unit
111: MCU 112:
113: LED 114:
120: Fuse 130: CT
140: SSR 200:
300: load 400: terminal

Claims (6)

1. A current monitoring board for protecting a circuit by disconnecting a fuse in an overcurrent,
An in-connector to which a power line is connected;
A fuse electrically connected to one end of the power line connected to the in-connector;
A relay electrically connected to the other end of the fuse;
A current transformer (CT) electrically connected to the relay;
An SSR (Solid State Relay) electrically connected to the CT;
An out connector to which an output line of the SSR and another line of the in-connector are connected;
A current monitor for monitoring the state of the electric energy signal induced by the CT and the state of the SSR control I / O control signal in real time to output an alarm signal in the event of an abnormality and outputting a control signal for shutting off the corresponding power;
Current monitoring board.
The method according to claim 1,
The current monitoring unit
A control unit for outputting the SSR control I / O control signal;
The CT controller receives an I / O signal for controlling the SSR of the control unit and determines whether or not an AC current conversion signal for each SSR is inputted. An MCU (Microprocessor) for judging whether or not the power supply is turned on;
The MCU transmits an alarm signal of the corresponding SSR to the control unit, and the controller illuminates an LED indicating the position of the fuse corresponding to the transmitted alarm signal to notify the replacement of the fuse, And a control signal for shutting off the power of the channel to the relay.
The method of claim 2,
The MCU
A communication unit for performing RS485 or RS422 communication with the external PLC;
A first rotary switch for selecting a current value of a current transformer according to a size of a load connected to the out connector;
A second rotary switch for setting a timing sensitivity of the SSR (Solid State Relay)
An AC current converter for converting electrical energy induced in the CT into a voltage through a current to voltage converter circuit and converting the converted voltage into an AC current converted signal converted from an AD converter into a digital value;
And a current monitoring board.
A control method of a current monitoring board for protecting a circuit by disconnecting a fuse during an overcurrent,
(a) selecting and setting a current value of a current transformer (CT) with a rotary switch according to a size of a load;
(b) setting a timing sensitivity of SSR (Solid State Relay) using another rotary switch;
(c) One of the power lines is connected to the direct load, one of the power lines flowing to the load is input to the AC input of the current monitoring board, and the fuse circuit block, CT, and SSR are electrically connected in sequence Connecting to the load;
(d) converting the electrical energy induced in the CT into an AC current conversion signal and inputting the converted AC current signal to the MCU;
(e) inputting the SSR I / O control signal of the control unit for controlling voltage and current flowing to the load to the microprocessor; and
(f) The MCU monitors the AC current conversion signal and the SSR I / O signal in real time to determine whether or not an AC current conversion signal for each SSR is input, determines whether the power source is energized or not, The control unit transmits an alarm signal of the corresponding SSR to the control unit. The control unit informs the replacement of the fuse by turning on the LED indicating the position of the fuse corresponding to the transmitted alarm signal, And controlling the power of the corresponding channel to be cut off;
And a control unit for controlling the current monitoring board.
The method of claim 4,
The step (d)
(d-1) inputting one line of the power supply line to the AC input of the current monitoring board;
(d-2) converting the electric energy induced in the CT to a voltage through a current to voltage converter circuit; and
(d-3) inputting an AC current conversion signal obtained by converting the voltage converted in the step (d-2) from the AD converter to a digital value to the MCU;
Further comprising the steps of: The method of claim 4,
(g) having at least two current monitoring boards and each current monitoring board communicating with each other or the PLC via RS485 or RS422 communication;
(h) transmitting alarm information generated in step (f) to an external terminal through a communication unit;
Further comprising the steps of:

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