YASKAWA JEPMC-CP3202-E

3.3 Multi-CPU Functions
Slave CPU Synchronization
3-108
Scan Overhead Guidelines When Using Sub CPU Synchronization
This section provides guidelines for the scan overhead times for the sizes of CPU interface registers for
high-speed and low-speed scans.
 CPU Interface Registers for High-speed Scan
This section describes the data transfer timing for CPU interface registers for the high-speed scans.
If the time set for the high-speed scan in the CPU Unit is shorter than the overhead time, a scan exceeded
error will occur and SW00044 (H Scan Exceeded Count) will be incremented. If that occurs, adjust the
high-speed scan set value based on the above table.
The following figure illustrates high-speed scan processing.
 CPU Interface Registers for Low-speed Scan
The following table gives approximate times for the low-speed scan overhead that is required for different
sizes of CPU interface registers for the low-speed scan.
If the time set for the low-speed scan in the CPU Unit is shorter than the overhead time, a scan exceeded
error will occur and SW00046 (L Scan Exceeded Count) will be incremented. If that occurs, adjust the
low-speed scan set value based on the above table.
The following figure illustrates low-speed scan processing.
Slave CPU Synchronization
Refer to the following manual for details on slave CPU synchronization.
MP3000 Series Motion Control User’s Manual (Manual No.: SIEP C880725 11)
Item
I/O Size
512 Words 1,024 Words 2,048 Words
Guideline Times for CPU Interface
Overhead
25 μs 50 μs 100 μs
Item
I/O Size
512 Words 1,024 Words 2,048 Words
Guideline Times for CPU Interface Overhead 100 μs 200 μs 300 μs
CPU interface DWG.H
SVC processing
(status)
SVC processing
(motion processing)
Current high-speed scan time
Overhead time
High-speed scan set value
CPU interface
High-speed scan
CPU interface DWG.L
Current low-speed scan time
Overhead time
Low-speed scan set value
CPU interface
Low-speed scan