Boots – shoes – and leggings
Patent
1987-11-25
1989-03-14
Smith, Jerry
Boots, shoes, and leggings
364200, 364900, 36447403, 364550, 371 16, 371 19, 371 21, G06F 1130, G11C 2900
Patent
active
048129640
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a signal tracing control system for a programmable machine controller PMC, and more particularly to a signal tracing control system for a PMC which is capable of storing data in a tracing buffer having a small capacity.
When trouble occurs during software development or operation of a controlled device, it is necessary to know the stored contents or data items of various memories in order to investigate the cause of the trouble. In this manner, it is more important to understand dynamic conditions, i.e., the process of a change, than to know static conditions. One system for knowing dynamic conditions has been to alter the program of a control apparatus and monitor a certain signal. However, if the program of the control apparatus is stored in a ROM, it cannot be altered. A system for storing the contents of a memory for a certain period of time is known as a system for monitoring the contents of the memory.
If the contents of a memory are to be stored as they are, the capacity of a memory used to store them must be large. If a memory of a certain storage capacity is used, the time during which the memory contents are monitored is limited. Therefore, memory data responsible for the trouble may not be discovered.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a signal tracing control system for a PMC which will solve the above problems and can effect a necessary monitoring process with a small memory capacity.
To solve the above problems, there is provided a signal tracing control system in a programmable machine controller (PMC) for controlling a machine in response to a signal from a numerical control apparatus, comprising monitoring means for monitoring a change in a signal of a monitored RAM, writing control means for writing data in response to a signal indicative of a signal change from the monitoring means, and a tracing buffer for storing the data of the monitored RAM which is written by the writing control means.
Since not all data items are traced, but a signal subjected to a change is monitored, effective signal tracing can be performed with a small memory capacity.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a signal tracing control system according to an embodiment of the present invention;
FIG. 2 is a flowchart of an operation sequence of the signal tracing control system; and
FIG. 3 is a block diagram of a hardware arrangement of the signal tracing control system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An embodiment of the present invention will hereinafter be described in specific detail with reference to the drawings.
FIG. 1 is in block diagram of a signal tracing control system according to an embodiment of the present invention. A RAM 10 in a PMC includes a monitored RAM 1 and a tracing buffer 2 for storing data stored in the RAM 1. A signal monitoring means 21 monitors how the stored data in the monitored RAM 1 changes. A writing control means 22 is responsive to a signal from the monitored RAM 1 for writing the data from the monitored RAM 1 into the tracing buffer 2.
The operation of the device in FIG. 1 will now be described briefly. First, an address to be monitored in the monitored RAM 1 is selected in advance. In the illustrated embodiment, addresses A and B (which are shown as hatched portions in FIG. 1) are monitored. The signal monitoring means 21 always monitors how the signals of the addresses A and B change. If any bit of the addresses A and B is changed, the writing control means 22 applies a signal indicating a bit change to the writing control means 22. In response to the signal from the signal monitoring means 21, the signal monitoring means 21 writes the data items of the addresses A and B into the tracing buffer 2. In the illustrated embodiment, the data item of address A is written into the lefthand side of an address 04 of the tracing buffer 2; whereas the data item of address B is written into the righthand side of the address 04 of the tracing buff
REFERENCES:
patent: 4063311 (1977-12-01), Jeremiah et al.
patent: 4195770 (1980-04-01), Benton et al.
patent: 4200936 (1980-04-01), Borzcik et al.
patent: 4590550 (1986-05-01), Eilert et al.
patent: 4598364 (1986-07-01), Gum et al.
patent: 4639917 (1987-01-01), Furuta
patent: 4757503 (1988-07-01), Hayes et al.
Kiya Nobuyuki
Saiki Yoshiharu
Toriyama Shuji
Fanuc Ltd.
Gordon Paul
Smith Jerry
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