Yaskawa MP940 - Manual (Page 57)

Basic System Operation
3.3.1 Overview of Scan Processing
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3.3 Scan Processing
3.3.1 Overview of Scan Processing
There are three types of MP940 scan processing: S (system) scans, H (high-speed) scans,
and L (low-speed) scans. Scan processing is executed using time slicing within the S-scan
cycle, with the S scan as the basic cycle.
Background processing time for PP processing must be ensured by setting a ratio for alloca-
tion to background processing within the S scan cycle.
„ Types of Scans
„ Service Scans for Each Function
Except for SVA, the scan for executing I/O processing can be selected for each function.
Scan Type Details
S scan (system scan) • Basic cycle for scan processing: Select 0.5, 1.0, 2.0, or
4.0 ms.
• S, H, and L scan processing is all executed with time slic-
ing within the S-scan cycle.
H scan (high-speed scan) • Set as an integer multiple of S-scan cycle.
• Executed with time slicing within S-scan cycle.
L scan (low-speed scan) • Set as an integer multiple of S-scan cycle.
• Executed with time slicing within S-scan cycle.
Function
Scans Possible for
Servicing
Remarks
CNTR S/H/L Processed in sync with S, H, or L.
LIO (DI/DO/AI/AO) S/H/L Processed in sync with S, H, or L.
MECHATROLINK
(distributed I/O, etc.) H/L Processed in sync with H, or L.
SVA S/H Scan fixed (not selectable).
Parameters can be set to select synchronization with the
Phase Control Mode and the Position Control Mode.
Phase Control Mode Synchronization Selection
(OBC0016)
0: H scan (default); 1: S scan
Position Control Mode Parameter Synchronization
Selection (OBC0017)
0: H scan; 1: S scan (default)