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6. APPLICATION FUNCTIONS
(2) Exclusive control procedure on user program side
The following shows the procedure to control the digital output signal exclusively.
(a) Exclusive control procedure
START
Set "1: Request" to the digital output signal
host occupy request (DORH).
END
Pre-processing of
exclusive control
Not permitted
Permitted
Time out
Post-processing of
exclusive control
Set "0: No request" to the digital output signal
host occupy request (DORH).
Set "1: User program" to the digital output signal
occupy selection (DOCS).
Check for occupy
permission (Note 1)
Reading digital output signal
Writing digital output signal
Note 1: Check for occupy permission
(2) Condition for occupy non-permission
When the during digital output signal board
occupy request (DORB) is "0: No request" or
the digital output signal occupy selection
(DOCS) is "0: System program"
When the during digital output signal board
occupy request (DORB) is "1: Request" and
the digital output signal occupy selection
(DOCS) is "1: User program"
(1) Condition for occupy permission
(b) Condition for occupy permission of digital output signal
DORH DORB DOCS Occupy status of digital output signal Occupy permitted/not permitted
0 0 0 No occupy
No occupy request from user
program.
0 0 1 No occupy
0 1 0 Occupied by system program.
0 1 1 Occupied by system program.
1 0 0 Occupied by user program.
Occupy permitted
1 0 1 Occupied by user program.
1 1 0
Occupied by user program.
(Waiting for permission from system program)
1 1 1
Occupied by system program.
(Waiting for permission from user program)
Occupy not permitted
(3) Restrictions
Perform the exclusive control so that the occupy time on the user program side is 5μs or less. If the
possessory right is not shifted to the system program even after 5μs at the timing in which the system
program accesses the digital output signal, the access to the digital output signal is stopped. When the access
to the digital output signal is stopped, the access put on hold until the next control cycle.