MITSUBISHI ELECTRIC MOTION CONTROLLERS Q172DCPU - Manual (Page 38)

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2 MULTIPLE CPU SYSTEM
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2. MULTIPLE CPU SYSTEM
2.1 Multiple CPU System
2.1.1 Overview
(1) What is Multiple CPU system ?
A Multiple CPU system is a system in which more than one PLC CPU module
and Motion CPU module (up to 4 modules) are mounted on several main base
unit in order to control the I/O modules and intelligent function modules.
Each Motion CPU controls the servo amplifiers connected by SSCNET cable.
(2) System configuration based on load distribution
(a) By distributing such tasks as servo control, machine control and information
control among multiple processors, the flexible system configuration can be
realized.
(b) You can increase the number of control axes by using a multiple Motion
CPU modules.
It is possible to control up to 96 axes by using the three CPU modules
(Q173DCPU).
(c) By distributing the high-load processing performed on a single PLC CPU
over several CPU modules, it is possible to reduce the overall system PLC
scan time.
(3) Communication between CPUs in the Multiple CPU system
(a) Since device data of other CPUs can be automatically read by the automatic
refresh function, the self CPU can also use them as those of self CPU.
(Note): When the High performance PLC CPU module/Process CPU
module/PC CPU module/C controller module is mounted in the
combination of Multiple CPU system, the Motion dedicated PLC
instruction from these modules cannot be executed.
(b) Motion dedicated PLC instructions can be used to access device data from
the PLC CPU to Motion CPU and start Motion SFC program.