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MELSEC-Q
10 DEVICES
(2) When the "High speed execution" check box is checked:
(a) If a scan execution type program/low speed execution type program is
switched to an interrupt program/fixed scan execution type program, index
register data will not be saved/restored.
(b) If data is written to index registers by using an interrupt program/fixed scan
execution type program, the values of index registers used for an scan/low
speed execution type program will be corrupted.
Executed program
Index register value
Scan/low speed
execution type
program
Z0=1
Z0=0
Z0=0
Index register storage area
For scan/low speed
execution type program
Interrupt program/
Fixed scan execution
type program
Z0=1 to Z0=3
Z0=0
Reset
Z0=0
Z0=3
Z0=0
Scan/low speed
execution type
program
: For interrupt program, Z0 is changed to 3.
Switch-
ing
Transf-
erred
Transf-
erred
(c) Before writing data to index registers by using an interrupt program/fixed
scan execution type program, use the ZPUSH/ZPOP instruction to
save/restore the data.
ZPUSH D0
SM400
ZPOP D0
SM400
IRET
The points after D0 stores the
data (Z0 to Z15).
The data after D0 is stored
in points (Z0 to Z15).
I0