JPS61170845A - Checking system of rom for sequence control - Google Patents

Abstract

PURPOSE:To check the outline of the operation of a ROM by dividing the memory area of the ROM into two blocks and storing check data in the second block. CONSTITUTION:Control data is stored in a part I of the memory area of a ROM1 of the test object, and check data is stored in a part II. When control is requested, an address signal A from an external controller is inputted to the ROM1 through a selector 2, and a prescribed control output is sent through a gate 4. Unless control is requested, the ROM1 is checked. In this check, the address input of the ROM1 is inputted to the ROM1 through the selector 2, and corresponding output data stored in the part II is sent back and inputted to the selector 2 through a flip flop 3. SInce the time required for the completion of the series of operations is a certain value at the normal operation time, this time is monitored by a counter to discriminate whether the operation is normal or abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a self-monitoring method for a control device, and particularly to a sequence control ROM check method in which a sequence control ROM is checked while the ROM is stopped.

Since the conventional ROM check method uses a large number of peripheral devices, the scale of the check is large and it is difficult to carry out the check.Therefore, it has been desired to develop a check method that can improve this problem.

[Conventional technology]

Conventional ROM check methods include one in which a pseudo operation is performed at systematic intervals to check the entire system including the ROM, and the other is a method in which a pseudo command is sent to the sequence control unit and the response is judged to determine the operation of the device. There was a way to check.

Both methods have the disadvantage that the equipment required for the check is large and the check operation takes too much time.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sequence control ROM check method which eliminates the drawbacks of the above-mentioned conventional methods, is simpler, and allows a general outline of the ROM operation to be checked.

[Means for solving problems]

The means to solve the problem is to divide the ROM memory area into two blocks, store control data in the first block, store 81°M check data in the second block, and store the 81°M check data in the second block. When the 8g ROM is not used for control, the control data of the first block is used, and when the 8g ROM is not used for control, the ROM check data of the second block is used. The second address of the second block is written in the first address of the second block, and the first address of the second block is written in the final address of the second block, thereby sequentially writing all the addresses of the second block. This is achieved by checking the stored contents.

[Operation] According to the present invention, as described in the section of means for solving the problems, data at all addresses in the second block of the ROM is automatically read out, and the quality of the operation during that time is determined. It produces the effect that it can be done.

〔Example〕

The figure is a diagram showing an embodiment of a sequence control ROM check method according to the present invention.

In the figure, 1 is a ROM, 2 is a selector, 3 is a free-knob flop, 4 is a gate, 5 is a data detector, and 6 is a counter.

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

ROMI is a ROM to be tested, and in its memory area, control data is written in the I part, and check data is written in the part ■.

When there is a control request, an address signal sent from an external control device passes through route A and enters ROMI via selector 2. As a result, the ROM corresponding to the address
The data stored in I (stored in the I portion of ROMI) is output through gate 4 to perform a predetermined control operation.

Also, if control 0 request "'output 7 pa 4°'"2!・1 invention'
” - Checks the ROM accordingly, i.e.
The address input of ROMI passes through route B and enters ROMI by selector 2, and the output data corresponding to that address stored in the part marked with ROMI is looped back via flip-flop 3, passes through route B, and enters selector 2.
is input. The gate 4 is closed when the direction is north/south, so the control output does not go outside.

When no control request is issued, specify the first address a in the part marked with ``■'' in the ROMI. As a result, the data written to address a is manually input to flip-flop 3. The data written to this address a is the next address b after address a.

Therefore, address b is specified next, and as a result, address b
The data written in is manually input to the flip-flop 3. The data written to this address b is the next address C after address b.

Therefore, address C is specified next, and the same procedure is followed for RO.
Read the ■ part of MI sequentially.

The time required for the above series of operations to complete takes a constant value in the case of normal operation, so the counter 6 monitors this time, and when it completes within a predetermined time, it is considered normal and other than this. If so, it is determined that there is an abnormality.

〔Effect of the invention〕

As described in detail above, the present invention has the great effect of being able to check the general outline of the operation of the ROM by adding an extremely simple circuit.

[Brief explanation of drawings]

The figure is a diagram showing an embodiment of a sequence control ROM check method according to the present invention. In the figure, l is a ROM, 2 is a selector, 3 is a flip-flop, 4 is a gate, 5 is a data detector, and 6 is a counter. 1 overstepping

Claims (1)

[Claims] The ROM memory area is divided into two blocks, the first block stores control data, and the second block stores the RO.
M check data is stored, and when the ROM is used for control, the control data of the first block is used, and when the ROM is not used for control, the control data of the second block is used. Using the ROM check data,
The second address of the second block is written in the first address of the second block, and the first address of the second block is written in the final address of the second block. A sequence control ROM check method characterized by checking the stored contents of all addresses.