Mitsubishi Electric QJ71E71-100 User Manual page 226

(3) Using MC protocol communications
The QnA-compatible 3E frame or 4E frame can be used to access the control system/standby system or system
A/system B.
(a) Operation performed for access to the control system/standby system or the system
A/system B
When the system is switched (example of access to the control system CPU module)
Ex.
Access to
the control system
Control system (system A)
Tracking cable
Access to the control
system is continued
via a tracking cable.
Standby system (system A)
Tracking cable
For access to the system that is not the connection destination (example of connection to the control
Ex.
system and access to the standby system CPU module)
Connected device
Access to
the standby system
Control system (system A) Standby system (system B)
Tracking cable
224
Connected device
QnA-compatible 3E frame
Request destination module I/O number:
03D0
H
Network number: 00
Personal computer number: FF
Standby system (system B)
Connected device
QnA-compatible 3E frame
Request destination module I/O number:
03D0
H
Network number: 00
Personal computer number: FF
Control system (system B)
QnA-compatible 3E frame
Request destination module I/O number:
03D1
H
Network number: 00
Personal computer number: FF
Even if an error occurs in the communication line,
it is possible to access the standby system.
1.
Connect the connected device to the E71
mounted with the control system CPU module
to access the control system CPU module.
H
H
2.
When the system is switched, the connected
device automatically continues access to the
control system through the tracking cable.
However, if the communication line with the
H
H
connection destination is faulty or the
standby system is powered off, for example,
the destination must be changed on the
connected device.
3.
To access the standby system CPU module,
the connected device connects to the E71
mounted with the control system CPU module
H
through the tracking cable. This enables
H
access even if the communication line
between the connected device and standby
system becomes faulty.