Electrical computers and digital processing systems: multicomput – Computer-to-computer data routing – Least weight routing
Reexamination Certificate
1995-12-06
2002-12-17
Banankhah, Majid (Department: 2156)
Electrical computers and digital processing systems: multicomput
Computer-to-computer data routing
Least weight routing
C709S241000
Reexamination Certificate
active
06496848
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a control method for a control software execution system, and more particularly to a control method for a control software execution system for an NC unit for efficiently executing software (a control program) for controlling a numerical control unit (described as NC unit hereinafter).
BACKGROUND OF THE INVENTION
FIG. 73
is a block diagram showing general configuration of a control software execution system for a conventional type of NC unit, and in this figure the reference numeral
501
indicates an NC unit as a whole. Description is made hereinafter for general configuration of the conventional type of NC unit with reference to the hardware configuration in this NC unit
501
.
In
FIG. 73
, designated at the reference numeral
1
is a main CPU for controlling operations of each section or executing computing required for numerical control, at
2
a system bus connecting section of the unit to each other, at
3
a ROM (non-volatile storage device) for storing control software or the like for realization of main functions of the NC unit
501
, at
4
a RAM (volatile storage device) used for temporal data storage or as a work area.
Also in this figure, designated at the reference numeral
5
is a SIO interface section for transacting data with external devices by means of serial communications, at
6
a display unit for displaying a running state of the NC unit
501
or identifying an command given to the NC unit
501
, at
7
a keyboard for giving commands to the NC unit
501
(input device), at
8
a servo control section for computing commands for controlling a servo motor. This servo control section
8
may comprise a dedicated CPU which is different from the main CPU
1
.
Also in this figure, designated at the reference numeral
9
is a servo amplifier for electrically amplifying an command received from the servo control section
8
and driving a servo motor or a main shaft of machine tool (not shown), at
10
a servo motor for controlling a machining section of machine tool (not shown), at
11
a programmable control section (described as PC section hereinafter) for transacting data other than commands for servo control with the machine tool, at
12
a system clock (not shown) and an external interrupt signal inputted to the main CPU
1
. The system clock is a clock signal for establishing synchronism for controlling the NC unit
501
as a whole. The external interrupt signal
12
is a signal for reporting an event (emergent state) such as power error or emergent stop to the main CPU
1
.
Next, a description is made for operations.
FIG. 74
is an explanatory view for explanation of a sequence for execution of analysis of a machining program for a control software execution system for the NC unit
501
shown in
FIG. 73
, and at first the main CPU
1
sequentially reads control software written in the ROM
3
via the system bus
2
, and executes the contents.
In
FIG. 74
, in a machining program input processing
21
, a machining program
20
is read via the SIO interface section
5
from the outside, and is stored in the RAM
4
. Then, each block (a prespecified unit decided for each machining program to be inputted) is converted to internal data which can easily be processed internally.
Also in a correction computing processing
22
, internal data for each block is processed and computed to obtain a travel. Also such parameters as a tool diameter or a tool length are corrected. Furthermore such operations as updation of internal coordinate values are executed. In a setting/display processing
23
, various type of data for the NC unit
501
are displayed in the display unit
6
. Also each of the various set-up data inputted by an operator using the keyboard
7
is stored in the RAM
4
. In addition, in an interpolation processing
24
, a travel for each shaft per minute time unit using a result of the correction computing processing
22
.
In a servo processing
25
, a result of the interpolation processing
24
is further converted to a travel for each shaft per minute time unit. Furthermore feedback control (not shown) is executed from a speed detector or a position detector (not shown herein) attached to the servo motor
10
or the machine tool (not shown) is executed. In a processing
26
by a programmable controller (described as PC hereinafter), control over peripheral devices around the machine tool such as input/output processing to and from the machine tool or the main shaft is executed.
As described above with reference to
FIG. 73
, the NC unit
501
can respond to an emergent state other than the normal processing flow such as emergency stop by receiving the external interrupt signal
12
and having interrupt processing executed. When the external interrupt signal
12
(Refer to
FIG. 73
) is inputted, the main CPU
1
executes a prespecified particular processing, and returns to the normal command after execution of the prespecified particular processing has been finished.
FIG. 75
is a concept view showing interrupt processing. In this figure, reference numerals
30
to
36
indicate a normal command,
37
to
40
indicate an interrupt command, and
41
indicates an command for return to normal command respectively. For instance, when an external interrupt signal
12
(Refer to
FIG. 73
) is inputted while the main CPU
1
executes a normal command
33
, the main CPU
1
detects an interrupt after execution of the normal command
33
, and starts execution of an interrupt command
37
specified previously. Then after execution of interrupt commands
37
to
40
is finished, the main CPU
1
executes the return command
41
, returns to the normal command
34
, and then executes normal commands
35
,
36
.
It should be noted that, if a time required for interrupt processing becomes longer, the possibility of multiple interrupt in which another interrupt is inputted during execution of interrupt processing becomes higher, and if any interrupt is inhibited during executing of interrupt processing, a quick response to an interrupt request becomes impossible, and for the reasons as described above it is desirable to make the time for interrupt processing as short as possible.
By the way, control software for the NC unit
501
has the features as described below.
At first, because of the variety of functions to be realized by the control software for the NC unit
501
, a number of required software is very large, and many people are required to be involved in development of the software.
Secondly, a response time (turn around time, dead line) required for execution of each function of control software for the NC unit
501
is different. For instance, in the servo processing
25
(Refer to FIG.
74
), if some delay occurs in computing a result of processing, cutting is stopped, a work becomes a defective product, so that real time processing is required. On the other hand, in such a processing as display on the display unit
6
, even if some delay occurs, not trouble is generated, so that real time processing is not required.
Thirdly, a processing by control software for the NC unit
501
is not of a batch type, nor of a compiler type (in which an entire machining program is analyzed from its beginning to the end and then all the moving data for a servo is outputted at once), but of an interpreter type (in which a machining program is divided to several blocks, the blocks are analyzed one by one, and also the moving data for servo is outputted little by little).
Fourthly, there are many types of interrupt processing to be executed by the main CPU
1
.
Because of these features, generally control software for the NC unit
501
is based on a real time operating system (described as RTOS hereinafter), and usually a task for each function to be executed under the control is regarded as an execution unit.
Next, a description is made for a method of controlling each task with the RTOS. To check dispatching priority of each task at a specified time interval or to delay execution of a task by a specified period of t
Banankhah Majid
Mitsubishi Denki & Kabushiki Kaisha
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