Precautions For Using Multiple Cpu System; Precautions For Using Hubs - Mitsubishi Electric Melsec Q Series User Manual

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SYSTEM CONFIGURATION

2.6.2 Precautions for using multiple CPU system

The following describes the precautions for using the multiple CPU system.
(1) Access to each CPU module at start-up of multiple CPU system

2.6.3 Precautions for using hubs

The following describes the precautions for using the hub.
(1) IEEE802.3x flow control in full-duplex communication
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- 23 2.6 Precautions for System Configuration
2.6.2 Precautions for using multiple CPU system
In the system in which a MES interface module is mounted in the multiple CPU
system, an error may occur when accessing other CPU from the MES interface
module or accessing the other station via a network module controlled by other CPU
from the MES interface module due to the difference of start-up time of each CPU
module. In this case, clear the error in the MES interface module after starting up
other CPU.
Page 10-3, Section 10.1.2 (2)
The start-up of other CPUs can be checked with the special relays, SM220 to SM223.
User's manual for the CPU module used
The MES interface module does not support the IEEE802.3x flow control.
Therefore, when the load of an Ethernet line is high in the connection with the hub
supporting IEEE802.3x, the data to be sent to the module may be lost.
If the above mentioned phenomenon occurs, add the hubs and reduce the load on the
Ethernet line applied on single hub.