JP2001025149A - Overcurrent protective system and overcurrent protecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce service cost for improving serviceability. SOLUTION: An appropriate protection is provided for overcurrent, such as a load short-circuit, using a poly-switch 33. Controllers 10, 20 detect the generating position of the load short-circuit for each unit 30, 40, store the frequency of the detection in a memory 103 as history data for the each unit 30, 40, and displays the history data on a display part 1, using a password or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a security protection system and method applicable to a copier or the like in which a service person opens the inside of an apparatus to perform work, and more particularly, to a secondary power supply for a copier or the like. The overcurrent protection circuit is provided on the side, and when the power supply is short-circuited due to a trouble, the overcurrent protection of the overcurrent protection circuit is activated, and when the cause is removed, the return type overcurrent protection returns to normal operation The present invention relates to a system and an overcurrent protection method.

[0002]

2. Description of the Related Art Conventionally, as an apparatus having an overcurrent protection circuit on the secondary side of a power supply, for example, in a copying machine, an overcurrent protection method using a switching regulator, or A method of providing an irreversible current fuse on an electric circuit board is generally used.

[0003]

However, in the above-mentioned conventional example, for example, in the case of a switching regulator, since it is applied to a plurality of load systems at the same time, it is necessary to increase the current value for overcurrent detection. As a result, when one point of the load is short-circuited, there is a problem that the signal line burns or the electric circuit board of the expensive load is damaged.

[0004] For this reason, a method of protecting each load or a group of loads with an irreversible current fuse is often applied.

However, in this case, if a short circuit is mistakenly made, the unit having the fuse is replaced, or even if the unit is configured such that only the fuse can be replaced, the fuse is blown. Since the system does not detect itself, it is not generally known whether the fuse is blown or not, and as a result, the unit is generally replaced.

Even in the case where only the fuse is replaced, the fuse rating varies for each load. A plurality of fuses need to be prepared by a service person, and the external shape of the fuse may change even if the rating changes. Since it is common that they are the same, there is a risk that a fuse of a different rating may be accidentally opened.

In this case, for example, when a fuse having a large rating is mistakenly attached, there is a problem that the original meaning of safety protection is lost.

An object of the present invention is to provide an overcurrent protection system and an overcurrent protection method capable of reducing service costs such as unit replacement and improving serviceability.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a return-type protection system for detecting an abnormality in a load, activating an overcurrent protection, and thereafter recovering the load. Overcurrent detection means for detecting the operation of each overcurrent protection means, and count of the number of times of operation of each of the overcurrent protection means detected by the overcurrent detection means are counted, and the count value is stored as history information. By providing backup means, an overcurrent protection system is configured.

Here, a display means for displaying the number of times of operation of each of the overcurrent protection means, which is held as the history information, may be further provided.

[0011] An input means for inputting data for decoding the history information may be further provided.

The history information decrypted by inputting the data can be displayed on the display means.

[0013] The overcurrent protection means may be a self-recoverable current limiting element of a variable resistance value type.

The self-returning current limiting element can be constituted by a polyswitch.

The present invention relates to an overcurrent protection method for detecting an abnormality of a load, activating an overcurrent protection, and thereafter recovering the load. The method comprises the steps of: detecting an operation of overcurrent protection means corresponding to each load; An overcurrent protection method is provided by including a step of counting the number of times of operation of each of the detected overcurrent protection means, and a step of retaining a count value by the counting as history information.

The present invention is a medium in which a program for detecting a load abnormality and controlling overcurrent protection by a computer is recorded, and the control program stores the program for overcurrent protection corresponding to each load. Means for detecting the operation of the means, counting the number of times of operation of each of the detected overcurrent protection means, and holding the count value by the count as history information. Is provided.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[Overview] First, an overview of the present invention will be described.

According to the present invention, there is provided a reset type overcurrent protection circuit which is provided on the secondary side of a power supply of a copying machine or the like, and after the overcurrent protection is activated, the normal operation is restored when the cause of the overcurrent protection is removed. In a current protection system, a means for detecting a change in resistance value of a self-recoverable current limiting element using a variable resistance type self-recoverable current limiting element as overcurrent protection means for each load, and a means for displaying the detected result. Means for easily pursuing the cause of the overcurrent flow, means for counting the number of detected results and backing up as a count value, and input means for inputting a password or the like for observing the backed up count result. Configure the system by

As the self-returning current limiting element, a reversible polyswitch can be used.

[Specific Example] Next, a specific configuration example of the present invention will be described.

FIG. 1 shows a configuration of an overcurrent protection system having an overcurrent protection circuit provided on a secondary side of a power supply according to the present invention. In this example, this protection system is applied to a copying machine in which a service person opens the inside of the apparatus and performs work.

First, the configuration of the present system will be described.

Reference numeral 1 denotes a display unit for displaying the name of the polyswitch that has caused a resistance trip and the number of times of integration.

As the display section 1, a liquid crystal is generally used in an ordinary copying machine. The liquid crystal display
It can be realized by a display font, display software, a liquid crystal controller, and the like.

Reference numeral 2 denotes a key input unit for displaying the accumulated count of the resistance trip. This key input unit 2
May be hard keys or a touch panel type liquid crystal display unit.

Reference numeral 10 denotes a CP for controlling the display unit 1.
This is a unit equipped with U. This unit 10
A CPU unit 11, various loads 12, a polyswitch 13 as an overcurrent limiting element, and a power input unit 14 are provided. Note that the overcurrent limiting element may be any element that has a variable resistance and is self-recovering.

The CPU unit 11 includes a CPU 100,
A ROM 101 for storing a program for system control or a program according to the present invention as shown in FIG.
AM102, backup RA for backing up a count value as history information indicating the number of times overcurrent detection has been activated
An M103, an I / O port 104, various CPU peripheral devices 105, and the like are provided.

The various loads 12 include electric parts on the substrate or external loads supplied with power from the unit 3.

The polyswitch 13 is an element for protecting a circuit by tripping a resistance value due to a temperature rise due to a trouble such as a load short circuit, and an element for flowing a small current without completely interrupting the current. .

The power input section 14 is a section for supplying power. The polyswitch 12 is connected between the power input unit 14 and various loads 12.

Reference numeral 20 denotes a CPU that does not directly control the display unit 1.
The unit is attached. The unit 20 includes a CPU unit 21, various loads 22, a polyswitch 23, and a power input unit 24.

Like the CPU unit 11, the CPU unit 21 includes a CPU 100, a ROM 101 for storing programs, a RAM 102 for work, a backup RAM 103, an I / O port 104, and various C
A PU peripheral device 105 is provided.

The various loads 22 include, similarly to the various loads 12, electric components on a substrate or external loads supplied with power from the unit 20.

The power input section 24 is a section for supplying power similarly to the power input section 14.

Numeral 30 denotes a unit having no CPU, and includes various loads 32, a polyswitch 33, and a power input unit 34.
It has. The configuration of each unit in the unit 30 is the same as the components in the units 10 and 20 described above.

Numeral 40 denotes a unit having no CPU, and includes various loads 42, a polyswitch 43, and a power input unit 44.
It has. The unit 40 includes the unit 30
This is the same configuration as.

50 and 51 are 10 kΩ in the unit 10
These are signal lines that are each pulled up by the high resistance r and input to the I / O port 104 of the CPU unit 11. These signal lines 50 and 51 are connected to the poly switches 33 and 43 of the units 30 and 40, respectively.

Numeral 52 is pulled up by a high resistance r of about 10 kΩ in the unit 10, and the I / O of the CPU unit 11 is
This is a signal line connected between the port 104 and the polyswitch 23 of the unit 20.

Numeral 53 is pulled up by a high resistance r of about 10 kΩ in the unit 20, and the I / O of the CPU unit 21 is
This is a signal line connected between the port 104 and the polyswitch 13 of the unit 10.

A communication signal line 54 connects the CPU unit 11 and the CPU unit 21.

(System Operation) Next, the operation of the present system will be described.

First, in step S1, periodic monitoring is performed. This regular monitoring is performed by a timer at regular intervals.
This is performed by monitoring the input level of the target I / O.

In step S2, it is checked whether or not a password has been input from the key input unit 2. If a password has been entered, the process proceeds to step S3, and if not, the process proceeds to step S10.

In step S3, it is checked whether or not a trouble such as a load short circuit has occurred in each unit of the present system.

Now, it is assumed that a trouble such as a blown fuse has occurred in the load in the unit 30. Thereby, the poly switch 33 minutely limits the current.

The polyswitch 33 is an element that trips and protects the resistance value due to a rise in temperature, and thus does not completely shut off the current. Once tripped, a small current keeps the switch temperature until the power is turned off. Retain protection function.

The signal line 50 connected to the polyswitch 33 is pulled up in the unit 10 with a high resistance of about 10 kΩ, and the I / O port 104 of the CPU unit 11
Is input to

In this case, during normal operation, HIGH is detected, but when the polyswitch 33 trips and becomes high resistance, the CPU unit 11 detects LOW. That is, when the LOW is detected, the overcurrent protection operation is detected.

When the signal line 50 is disconnected, for example, when the interface connector is disconnected,
Since it becomes HIGH, it can be distinguished from a resistance trip.

By detecting such a trouble, the process proceeds to step S4.

In step S4, the CPU unit 11
Detects the resistance trip, the backup RAM 1
Polyswitch 33 of the trouble object stored in 03
The integrated trip number N is read as a count value corresponding to.

In step S5, 1 is added to the read integrated trip number N, and the count value is set to n.

In step S 6, the new count value n is stored again in the backup RAM 103.

In step S7, it is checked whether or not the CPU unit is a unit connected to the display unit 1. If the unit is connected to the display unit 1, the process proceeds to step S8. If the unit is not connected, the process proceeds to step S9.

In step S8, the display unit 1 displays information indicating which polyswitch, and a message indicating that the cause of the overcurrent protection has to be solved because it has been activated. In this example, a message is displayed indicating that a trouble has occurred in the load of the unit 30 and that the fuse has blown.

In step S9, the main power supply is changed from off to on, and the system is reset. Thereafter, the flow returns to step S1 again to newly monitor the occurrence of a trouble.

The same operation is performed when overcurrent detection is activated in the unit 40 due to a load short circuit or the like.

Further, when a short circuit of the load or the like occurs in the unit 20 which does not control the display unit 1 but has the CPU, the flow is the same as the processing in the units 30 and 40.

On the other hand, if a short circuit occurs several times in the same load system, it is considered that the current limiting element is defective or the hardware is defective. In such a case, a possible unit is replaced. There is a need to. As a criterion, a password is entered from the key input unit 2 as an operation unit, and the total number of trips of the current limiting element (count value n)
Is effective for each unit.

Therefore, in step S10, the input of the password is confirmed.

In step S11, when a password or the like is input from the key input unit 2, it is selected whether or not to display the information content regarding the total number of trips. When displaying, the process proceeds to step S12, and when not displaying, the process proceeds to step S13.

In step S12, information including the total number of trips of the polyswitch desired to be viewed is displayed on the display unit 1.

In step S13, the accumulated trip count is cleared and initialized.

In the case where the integrated content displayed as described above has occurred several times, there is a possibility that the performance of the polyswitch itself may be degraded, or that an overcurrent may occur periodically which is difficult to find. Judge that there is. In this case, even if the device operates normally once, the same trouble may occur again. Therefore, work such as replacement of the unit which may cause the trouble is required.

Then, the process proceeds to step S9, where the main power supply is turned off / on, and after the system is reset, new monitoring is performed again.

Next, another processing example will be described.

In a unit including a CPU that directly controls the display unit 1, that is, in the unit 10 itself, when a load short circuit occurs, and especially, the operation of the CPU itself or the power supply system related to the liquid crystal display is protected from overcurrent. In this case, the contents cannot be displayed on the display unit 1. In this case, in the unit that does not directly control the display unit 1 but includes the CPU, that is, in the unit 20, the CPU unit 21 detects the operation of the overcurrent protection function in the unit 10 through the signal line 53.

As a result, the CPU unit 21 reads the accumulated trip number N of the target polyswitch from the backup RAM 103 and adds 1 to it (n = N).
+1), and the count value n is stored in the backup RAM 103 again.

In this case, since nothing is displayed on the display unit 1, the serviceman suspects that the load of the unit 10 is short-circuited, checks it with a tester or the like, and turns off / on the main power supply if the cause is solved. Do. As a result, CP
The U unit 21 communicates with the CPU unit 11 via the signal line 54 to display on the display unit 1 that the target protection circuit has been activated.

The present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.).
The present invention may be applied to an apparatus including two devices (for example, a copying machine and a facsimile machine).

It is needless to say that the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus. Then, a storage medium storing a program represented by software for achieving the present invention is supplied to a system or an apparatus, and the computer (or CPU or M) of the system or the apparatus is supplied.
(PU) reads out and executes the program code stored in the storage medium, so that the effects of the present invention can be enjoyed.

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, magnetic tape, nonvolatile memory card, ROM
(A mask ROM, a flash EEPROM, or the like) can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written in a function expansion port inserted into the computer or a memory provided in a function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0077]

As described above, according to the present invention,
Appropriate protection is provided by using overcurrent protection means against overcurrent such as load short circuit, and the control device detects the location of load short circuit for each unit, and the number of times of detection is stored in the memory for each unit. Since the history information is stored and displayed on the display unit using a password or the like, the cause of the load short can be easily tracked by a service person, and after the cause is resolved, the device is not broken. In this case, it is possible to smoothly shift to the normal operation as it is, thereby eliminating unnecessary unit replacement work, reducing service cost, and improving serviceability.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an overcurrent protection system according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of the present system.

[Explanation of symbols]

 Reference Signs List 1 display unit 2 key input unit 10 unit 11 CPU unit 13 polyswitch 20 unit 21 CPU unit 23 polyswitch 30 unit 33 polyswitch 40 unit 43 polyswitch 100 CPU 101 ROM 102 RAM 103 backup RAM 104 I / O port 105 peripheral device

Claims (18)

[Claims] 1. A recovery type protection system that detects an abnormality in a load, activates overcurrent protection, and thereafter recovers the load. An overcurrent protection unit corresponding to each load, and an operation of each overcurrent protection unit. Overcurrent detection means for detecting the number of times of operation of each of the overcurrent protection means detected by the overcurrent detection means, and backup means for holding the count value as history information Characterized overcurrent protection system. 2. The overcurrent protection system according to claim 1, further comprising display means for displaying the number of times of operation of each of said overcurrent protection means, which is held as said history information. 3. The overcurrent protection system according to claim 1, further comprising input means for inputting data for decoding the history information. 4. The overcurrent protection system according to claim 3, wherein said history information decoded by inputting said data is displayed on said display means. 5. The overcurrent protection system according to claim 1, wherein said overcurrent protection means is a self-recoverable current limiting element of a variable resistance value type. 6. The overcurrent protection system according to claim 5, wherein said self-recoverable current limiting element comprises a polyswitch. 7. An overcurrent protection method for detecting an abnormality of a load, activating overcurrent protection, and thereafter recovering the load, wherein a step of detecting an operation of overcurrent protection means corresponding to each load; An overcurrent protection method, comprising: counting the number of times of operation of each of the overcurrent protection means; and holding a count value obtained by the counting as history information. 8. The overcurrent protection method according to claim 7, further comprising the step of displaying the number of times of operation of each of said overcurrent protection means held as said history information. 9. The method according to claim 7, further comprising a step of inputting data for decrypting the history information.
Or the overcurrent protection method according to claim 8. 10. The overcurrent protection method according to claim 9, wherein the history information decoded by inputting the data is displayed. 11. The overcurrent protection method according to claim 7, wherein said overcurrent protection means is a variable resistance type self-recoverable current limiting element. 12. The overcurrent protection method according to claim 11, wherein said self-recoverable current limiting element comprises a polyswitch. 13. A medium on which a program for detecting a load abnormality and controlling overcurrent protection by a computer is recorded, wherein the control program causes a computer to execute overcurrent protection means corresponding to each load. Detecting an operation, counting the number of times of operation of each of the detected overcurrent protection means, and holding a count value by the count as history information. Medium on which is recorded. 14. The medium according to claim 13, wherein the number of actuations of each of said overcurrent protection means stored as said history information is displayed. 15. The system according to claim 13, wherein data for decrypting the history information is input.
A medium on which the overcurrent protection control program according to 4 is recorded. 16. The medium according to claim 15, wherein the history information decoded by inputting the data is displayed. 17. The overcurrent protection control program according to claim 13, wherein said overcurrent protection means is a variable resistance self-recoverable current limiting element. Medium. 18. The medium according to claim 17, wherein said self-recoverable current limiting element comprises a polyswitch.