JP2002229608A - Programmable controller and controlling method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controlling method for programmable controller allowing a user to individually set a secrecy level according to a use of the user. SOLUTION: In the programmable controller 100 for controlling secrecy by inputting a password from a password inputting part 109, an allowable number of times of input mistakes of the password and a restoring condition (time till restoring to a state for permitting a re-input of the password) are set in a secrecy level setting part 108, the reception of the password from the password inputting part 109 is inhibited when the number of times of input mistakes of the password from the password inputting part 109 exceeds the allowable number of times set in the secrecy level setting part 108 and subsequently the acceptance inhibiting state of the password is unlocked and the password is accepted only when the restoring condition is satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a programmable controller for managing confidentiality by inputting a password, and a control method therefor. The present invention relates to a programmable controller and a control method thereof.

[0002]

2. Description of the Related Art Generally, a programmable controller (PLC) is provided with a password function for protecting specific information with a password in order to manage confidentiality of a user program or the like.

For example, in the case of performing read protection of a specific user program using a password, input of a password is required when reading the specific user program. If a correct password is not input here, the specific user program is read. Program reading is prohibited.

[0004] By the way, in confidentiality management using the password, strict management is required, and conversely, flexible management is required.

In general, in a system in which the number of allowable password errors is set to be unlimited, if a device that automatically inputs all combinations of passwords is used,
Since the password is easily decrypted, if strict management is required, the function for setting confidentiality does not satisfy the condition, so it is necessary to limit the allowable number of input errors.

On the other hand, when flexible management is required, for example, the allowable number of password entry errors is limited to three times, and if the password entry errors are repeated three times, the system is restored at that point. If the configuration is made impossible, the system will not accept a password if the operator makes an input error only three times, for example, when the operator forgets the password, which is too strict as a security maintaining function.

[0007] Recently, in programmable controllers, demands for security of user programs have been increasing. Also, the use of the programmable controller has been diversified, and it has been impossible to uniquely determine the security level by password as a system.

[0008] Therefore, it is very useful for a maker providing a system and a provided user to allow a user to set a security level according to a use application.

However, in the conventional programmable controller, when the password read protection is set, the allowable number of password input errors and the method of restoring the system when the number of password input errors exceeds the allowable number are determined in advance by the system. It was decided in.

FIG. 5 is a flowchart showing a password processing procedure in a conventional programmable controller.

In FIG. 5, when a password is input to the programmable controller (step 501), first, whether the input password is correct, that is,
It is checked whether the input password matches a password preset in the programmable controller (step 502).

If it is determined that the passwords match (YES in step 502), the password is accepted by this programmable controller (step 50).
5) For example, reading of the user program of the programmable controller is permitted.

However, if it is determined in step 502 that the passwords do not match (NO in step 502),
Next, it is checked whether the number of input errors in which the passwords do not match has reached n times (for example, three times) preset in the system (step 503).

If it is determined that the number of password input errors has not reached n (NO in step 503),
Returning to step 501, re-input of the password is permitted.

However, if it is determined in step 503 that the number of password entry errors has reached n (step 503).
And the password is invalidated (step 5).
04), the system stops accepting passwords.

As described above, in the conventional password processing procedure of the programmable controller, the confidentiality level is uniquely determined by the system. For example, when the number of password input errors reaches a predetermined number set in the system, This programmable controller becomes inoperable, and there is a problem that subsequent processing cannot be performed.

[0017]

SUMMARY OF THE INVENTION Therefore, the present invention
It is an object of the present invention to allow a user to individually set the security level according to the usage of the user, thereby enabling flexible password operation.

Further, the present invention provides a programmable controller in which the user can individually set the confidentiality level according to the use of the user, and the user can operate the password flexibly. With the goal.

Further, the present invention provides a control method of a programmable controller in which a user can individually set the security level according to the use of the user, and the user can flexibly operate a password. The purpose is to provide.

[0020]

A programmable controller according to the present invention is a programmable controller for managing confidentiality by inputting a password. In the programmable controller, an allowable condition setting means for enabling a user to set an allowable condition of the password input error. And prohibiting means for prohibiting acceptance of the password when the password input error exceeds the allowable condition set by the allowable condition setting means.

[0021] In the programmable controller according to the present invention, in a programmable controller that manages confidentiality by inputting a password, a user can set a recovery condition for returning the password rejection prohibited state to the reception permitted state. Recovery condition setting means;
When the restoration condition set by the restoration condition setting means is satisfied, the apparatus further comprises cancellation means for canceling the password prohibition state and returning the password to the acceptable state.

According to a control method of a programmable controller according to the present invention, in a control method of a programmable controller for managing confidentiality by inputting a password, a user sets an allowable condition of the password input error, and When the allowable condition is exceeded, acceptance of the password is prohibited.

According to a control method of a programmable controller according to the present invention, in the control method of a programmable controller which manages confidentiality by inputting a password, a user may set a recovery condition for returning the password acceptance prohibited state to the acceptance permitted state. Is set, and when the recovery condition set by the recovery condition setting means is satisfied, the password reception prohibition state is released and the password is returned to the reception permission state.

Here, the input error allowable condition can be set by the number of password input errors.

The recovery condition can be set as a time from when the acceptance of the password is prohibited to when the state is restored to a state where the acceptance of the password is permitted.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a programmable controller and a method of controlling the same according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a schematic configuration of a programmable controller according to the present invention.

In FIG. 1, a programmable controller (PLC) 100 includes an MPU (Micro Processing).
Unit) 101, internal memory 102, data memory 10
3. System program memory 104, user program memory 105, bus I / F (bus interface)
106, a display 107, a security level setting unit 108,
The password input unit 109 is configured to be mutually connected by a system bus 110.

Here, the MPU 101 controls the overall operation of the programmable controller 100.

The internal memory 102 stores internal data of the programmable controller 100, and the data memory 103 stores various data. Programmable controller 100 according to the present invention
The password set in the data memory 103 is unique to the programmable controller 100.
May exist in the user program memory 105 as a part of the user program.

The system program memory 104 stores the system program of the programmable controller 100, and the user program memory 105 stores
A user program used by the user of the programmable controller 100 is stored.

The bus I / F 106 includes a system bus 110
An I / O unit, a high-performance unit, and the like (not shown) are connected via the bus I / F 106.

The display 107 is an LCD (Liquid Crystal).
Display), which displays various information related to the operation of the programmable controller 100.

The password input section 109 is composed of a plurality of key switches, and is for inputting a password.

The confidentiality level setting unit 108 sets an allowable condition setting unit that allows the user to set an allowable condition for password input error, and sets a recovery condition for returning a password prohibited state to an acceptable state. This function functions as a recovery condition setting means that can be set by the user. The specific contents of the setting conditions and the recovery conditions are described later.

In the programmable controller 100 according to this embodiment, the security of the password is determined for the purpose of the programmable controller 100 based on the password input error allowable condition and the recovery condition set by the user in the security level setting unit 108. It is flexibly controlled accordingly.

The password input error allowable condition is a password input error allowable condition from the password input unit 109, and is set here by the number of input errors.

The recovery condition is set by time. The time of the recovery condition is such that the password is accepted again from the point at which the acceptance of the password is prohibited, since the number of password entry errors entered from the password input unit 109 exceeds the entry error allowable condition, That is, it is the time until the password is restored to the state where the re-input is permitted.

In the programmable controller 100 of this embodiment, the confidentiality level of the programmable controller 100 is set in accordance with both the above-mentioned input error allowable condition and recovery condition.

Regarding the setting of the input error allowable condition (the number of password input errors in the present embodiment), there is no limit on the number of input errors, or an input such as 0, 1 or 5 times. A setting for limiting the number of misses is possible.

As for the setting of the recovery condition (in this embodiment, the time until the password is re-entered), it is possible to set from the absence to the minimum unit time.

The setting of the input error allowable condition and the setting of the recovery condition as described above can be arbitrarily performed by the user according to the application. Therefore, it is left to the user to determine the security level, and the user can set any security level suitable for the purpose independently and freely.

The level of the security level depends on the user's consciousness, but the level of the security level and the contents of the level are exemplified below.

In the programmable controller 100, when it is desired to set the confidentiality level to the "low" level, the input error allowable condition is set to be unlimited. In this case, the password can be re-entered no matter how many times the password is incorrectly entered, which is suitable for a case where a relatively low security level is acceptable.

When it is desired to set the confidentiality level to the "medium" level, for example, the allowable condition of an input error is set to five times,
Set the recovery condition to 2 hours. In this case, if the password input error is repeated five times, the password cannot be re-entered, and the user must wait two hours to recover the password from this state to a possible state.
Therefore, this example is suitable when a security level higher than the above example is required.

Further, when it is desired to set the confidentiality level to the "high" level, for example, the input error allowable condition is set to one and the recovery condition is set to none. In this case, once a password entry error is made, the password cannot be re-entered. In this state, the password cannot be re-entered after a number of hours. Therefore, this example is suitable when a higher security level than any of the above examples is required.

FIG. 2 is a flowchart showing a password processing procedure in the programmable controller 100 shown in FIG.

Referring to FIG. 2, the password input unit 109 shown in FIG.
Is entered (step 201), first, whether the entered password is correct, that is,
The input password is compared with a password set in advance in the data memory 103 or the user program memory 105 of the programmable controller 100, and it is checked whether they match (step 202).

If it is determined that the passwords match (YES in step 202), the password is accepted by the programmable controller 100 (step 207).
Reading of a specific user program stored in the user program memory 105 is permitted.

However, if it is determined in step 202 that the passwords do not match (NO in step 202),
Next, the number of input errors where the passwords do not match is determined by the allowable number of input errors n set by the confidentiality level setting unit 108.
(For example, 5 times) is checked (step 20).
3).

Here, if it is determined that the password input error has not reached n times (NO in step 203),
Returning to step 201, re-input of the password is permitted.

However, if it is determined in step 203 that the password input error has continued many times and the password input error has reached n times (YES in step 203), the password is rejected (step 203). 204) Next, it is checked whether the recovery time t set by the security level setting unit 108 has elapsed (step 205).

If it is determined that the recovery time t has not elapsed (NO in step 205), step 205
Return to During this time, the password rejection state is maintained.

However, if it is determined in step 205 that the recovery time t has elapsed (YES in step 205),
The password non-acceptance state is canceled (step 206), and the process returns to step 201, where re-input of the password is permitted.

The recovery time t may be reset when the power of the programmable controller 100 is turned off, and the time t may be measured again after the power is turned on.

FIG. 3 is a flowchart showing a procedure for processing a password configured as described above.

In FIG. 3, the password input unit 109 shown in FIG.
Is entered (step 301), first, whether the entered password is correct, that is,
It is checked whether the input password matches a password preset in the data memory 103 of the programmable controller 100 (step 30).
2).

If it is determined that the passwords match (YES in step 302), the password is accepted by the programmable controller 100 (step 310).
Reading of a specific user program stored in the user program memory 105 is permitted.

However, if it is determined in step 302 that the passwords do not match (NO in step 302),
Next, it is checked whether the number of input errors where the passwords do not match has reached the allowable number n (for example, 5) of input errors set by the confidentiality level setting unit 108 (step 3).
03).

If it is determined that the number of password input errors has not reached n (NO in step 303),
Returning to step 301, re-input of the password is permitted.

However, if it is determined in step 303 that the number of password input errors has reached n times (step 303).
YES), the password is rejected (step 304), and then the programmable controller 10
Start the timer provided in 0 (step 3
05).

Next, it is checked whether or not the time counted by the timer has passed the recovery time t set by the security level setting unit 108 (step 306).

If it is determined that the recovery time t has elapsed (YES in step 306), the password non-acceptance state is canceled (step 309), and the process returns to step 301, where re-input of the password is permitted.

However, if it is determined at step 306 that the recovery time t has not elapsed (N at step 306
O), keep time.

FIG. 4 is a diagram for explaining the operation when the power of the programmable controller 100 is turned off while waiting for the elapse of the time t in step 306 of the password processing procedure shown in FIG.

In FIG. 4, the password match is not obtained, and the timer shown in step 305 of FIG. 3 is started at time t1. However, at time t2 when the time counted by this timer does not reach the recovery time t, the programmable controller 100 When the power is turned off, the timer is reset to an initial value and restarted at time t3 when the power is turned on thereafter. Therefore, even if the password is input between the time point t3 when the power is turned on and the time point t4 when the recovery time t elapses, the password is not accepted.

Then, the password can be accepted only after time t4 when the recovery time t has elapsed from time t3 when the power is turned on.

According to such a configuration, for example, even if the password cannot be matched and the programmable controller 100 is turned off and replaced for illegal analysis of the password, the timer is turned on when the power is turned on. Is restarted, the password is not accepted at least during the recovery time t set by the security level setting unit 108.

[0069]

As described above, according to the present invention, in a programmable controller that manages security by inputting a password, the user can individually set the security level according to the intended use of the user. With this configuration, the user has a higher degree of freedom in setting a level for managing the confidentiality, and has an effect that a flexible password can be operated according to the user's intended use.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a programmable controller according to the present invention.

FIG. 2 is a programmable controller 10 shown in FIG.
FIG. 9 is a flowchart showing the procedure for processing a password at 0.

FIG. 3 is a programmable controller 10 shown in FIG.
FIG. 11 is a flowchart illustrating another processing procedure of the password at 0.

FIG. 4 is an exemplary view for explaining the operation when the password processing procedure shown in FIG. 3 is adopted;

FIG. 5 is a flowchart showing a password processing procedure in a conventional programmable controller.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 Programmable controller (PLC) 101 MPU (Micro Processing Unit) 102 Internal memory 103 Data memory 104 System program memory 105 User program memory 106 Bus I / F (Bus interface) 107 Display 108 Security level setting unit 109 Password input unit 110 System bus

Claims (6)

[Claims] 1. A programmable controller for managing confidentiality by inputting a password, an allowable condition setting means for enabling a user to set an allowable condition of the password input error, and setting the allowable condition of the password input error. A prohibiting means for prohibiting the acceptance of the password when the allowable condition set by the means is exceeded. 2. A programmable controller which manages confidentiality by inputting a password, wherein a recovery condition setting means for allowing a user to set a recovery condition for returning the password rejection state to the rejection allowable state; A programmable controller comprising: a release unit that releases the password prohibition state and returns the password to the acceptable state when the recovery condition set by the condition setting unit is satisfied. 3. The programmable controller according to claim 2, wherein the recovery condition is set as a time from when the acceptance of the password is prohibited to when the password is restored to a state where the acceptance of the password is permitted. . 4. A control method of a programmable controller for managing confidentiality by inputting a password, wherein a user sets an allowable condition of the password input error, and when the password input error exceeds the allowable condition, A method for controlling a programmable controller, wherein the reception of the password is prohibited. 5. A control method of a programmable controller for managing confidentiality by inputting a password, wherein a user sets a recovery condition for returning the password prohibited state to an acceptable state, and the recovery condition setting means sets the recovery condition. A method of controlling a programmable controller, wherein, when the set recovery condition is satisfied, the password rejection prohibited state is released and the password rejection state is restored. 6. The programmable controller according to claim 5, wherein the recovery condition is set as a time from when the acceptance of the password is prohibited to when the password is restored to a state where the acceptance of the password is permitted. Control method.