Omron SYSMAC CJ Series, Operation Manual

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Practical examples Section 5-2
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5-2 Practical examples
5-2-1 SHELL program
Good programming practice requires a good SHELL program. A SHELL
program starts, stops and resets the application programs. The SHELL
program is not necessary, but gives structure to the applications and makes
the method to program the motion controller more effective.
The purpose of the SHELL program is to ensure the proper initialization of
your system and the integrity of your machine. The example in the next
section can be used as a template and can be modified if required.
A SHELL program needs to ensure the next operations:
• the declaration of constants and global variables
• the correct initialization of the system by checking if the correct hardware is
used and by initializing all necessary parameters in the drives and
controller
• the error handling to start, stop and reset the application programs and to
report the status to the user.
Stop Application
programs and
movements
loop
Yes No
Stop
Application
programs
and
movements
System initialization
Other monitoring
Start
Application
programs
Reset
sequence
Update of status
GLOBAL &
CONSTANTdefinition
Alarm?
Yes No
Start?
Yes No
Stop
Application
programs
and
movements
Stop?
Yes No
Stopped?
Yes No
Reset?