Mitsubishi Electric MELSEC-Q Series User Manual page 246

7 ONLINE MODULE CHANGE
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(3) Saving data
After a module is changed, values in the buffer memory areas return to default
(values read from FeRAM). Save and restore data in the buffer memory to
continue previous operating status in the changed module.
However, if data can be restored using sequence programs or initial settings, the
save and restore processing is not required.
Data in the entire write-enable buffer memory area are required to continue the
operating status. There are two methods to save the data in the buffer memory.
(a) Specify the buffer memory of the change-target module on the Read from
PLC screen ("Device data" tab) of GX Developer and read data from the
buffer memory.
(b) Monitor the buffer memory of the change-target module on the Buffer
memory batch monitor screen of GX Developer and write down data in the
buffer memory.
Each operation should be performed before online module change, because they
cannot be performed after online module change has started. For operating
procedure, refer to Section 7.3.
(4) Wiring
Perform wiring after checking that the external power supply of current output is
off.
MELSEC-Q
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