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MELSEC-Q
7 ONLINE MODULE CHANGE
7 ONLINE MODULE CHANGE
This chapter describes the specifications of an online module change.
(1) Perform an online module change by oper ating GX Developer.
(2) To ensure ease of offset/gain re-setting, t here is a user range save/restoration
function that is performed by executing the dedicated instruct ion or read/write
from/to buffer memory.
POINT
• Perform an online module change after mak ing sure that the system outside the
PLC will not malfunction.
• To prevent an electric shock or like, always s witch OFF the external power of the
module that will be changed online.
• After the module has failed, data may not b e saved properly. Referring to Section
3.4.15, therefore, prerecord the data to be saved (offset/gain values of the
industrial shipment settings and user range s ettings in the buffer memory).
(Note)
The dedicated instruction cannot be executed dur ing an online module change. When
using the dedicated instruction to execute save/restoration , therefore, execute
save/restoration in the other system.
If the other system is unavailable, execute r estoration by performing write to the buffer
memory.

7.1 Online Module Change Conditions

The CPU, A/D converter module, GX Developer and base unit given below are ne ed ed
to perform an online module change.

(1) CPU

The Q12PHCPU or Q25PHCPU is needed. Note that it c annot be used on the
remote I/O station of the MELSECNET/H.
For precautions for multiple PLC system configuration, refer to the Process CPU
User's Manual (Function Explanation/Program Fundamentals).

(2) A/D converter module

The module of function version C or later is necessary.

(3) GX Developer

GX Developer of Version 7.10L or later is necessary.

(4) Base unit

1) For an online module change, use the main base unit and Q6 B extension
base unit.
The module installed on the main base unit or Q6 B extension base unit can
be change online.
2) The module installed on the Q5 B extension base unit cannot be changed
online.
When the Q5 B is in use, the module installed on the main base unit cannot
be changed online, either.
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