7 - 90 7 - 90
MELSEC-Q
7 FUNCTION
(4) Items to be noted in addition to (1) to (3)
(a) If "High speed execution" is selected at the "Interrupt program/fixed scan
execution program setting" section on the "PLC system" tab screen in thd
"(PLC) parameter" dialog box of GX Developer, this setting is invalid for the
high speed interrupt function.
(b) Using the file registers outside the setting range (range in excess of the
maximum number of points) for high speed buffer transfer does not result in
an error and does not transfer data to outside the range. (The contents of
the other devices are not corrupted.)
(c) As in the other interrupt programs, there are the following items as
precautions for program creation.
1) The device turned on by the PLS instruction in the high speed interrupt
program remains on until the same interrupt program is executed again.
2) While the high speed interrupt program is executed, DI (interrupt disable)
is established. Do not execute the EI/DI instruction in the high speed
interrupt program.
3) Timers cannot be used in the high speed interrupt program.
4) If the high speed interrupt program is executed during time measurement
such as scan time or execution time measurement, the high speed
interrupt program running time is added to the measurement time.
Hence, if the high speed interrupt program is executed, the values to be
stored into the following special registers and the monitor values of GX
Developer become longer than the values when the high speed interrupt
program is not executed.
(Special registers)
•
SD520, SD521: Current scan time
• SD522, SD523: Initial scan time
•
SD524, SD525: Minimum scan time
•
SD526, SD527: Maximum scan time
•
SD528, SD529: Current scan time for low speed
•
SD532, SD533: Minimum scan time for low speed
•
SD534, SD535: Maximum scan time for low speed
•
SD540, SD541: END processing time
•
SD542, SD543: Constant scan waiting time
•
SD544, SD545: Low speed program cumulative execution time
•
SD546, SD547: Low speed program execution time
•
SD548, SD549: Scan program execution time
•
SD551, SD552: Service interval time
(GX Developer monitor values)
•
Execution time measurement
•
Scan time measurement
•
Constant scan
