Redundant System Function; System Switching Request To The Control System Cpu Module - Mitsubishi Electric QJ71E71-100 User Manual

14.7

Redundant System Function

This section describes functions used when the E71 is mounted on the main base unit in a redundant system.
Remark
When the E71 is mounted on an extension base unit, skip this section.
14.7.1

System switching request to the control system CPU module

This function issues a system switching request to the control system CPU module if the E71 mounted with the control
system CPU module in a redundant system detects a communication error or disconnection.
(1) Conditions under which a system switching request is issued
The E71 issues a system switching request when the following conditions are satisfied.
Condition
Alive check
Communication error
detection
ULP timeout
Disconnection detection
In the following cases, system switching is not performed even if the E71 issues a system switching request.
• When the standby system has already been in error status (due to such as power-off, reset operation, and stop
error)
• The network module redundant group settings have been configured for the E71 and either one is operating
normally.
A communication
error occurred.
Control system (system A)
System switching request
After a connection is opened, the existence of the connected device cannot be
confirmed.
An ACK response is not returned from the connected device within the TCP ULP timer
time.
The cable connected to the E71 has been disconnected (the QJ71E71-100 only).
Connected device
Standby system (system B)
Tracking cable
Description
CHAPTER 14 OTHER FUNCTIONS
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