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MELSEC-Q
7 ONLINE MODULE CHANGE
7 ONLINE MODULE CHANGE
When changing a module online, carefully read the following manual.
• QCPU User’s Manual (Hardware Design, Maintenance and Inspection)
This chapter describes the specifications of an online module change.
(1) Perform an online module change by operating GX Developer.
(2) To ensure ease of offset/gain re-setting, there is a user range save/restoration
function that is performed by executing the dedicated instruction or read/write
from/to buffer memory.
POINT
(1) Perform an online module change after making sure that the system outside
the programmable controller will not malfunction.
(2) To prevent an electric shock and malfunction of operating modules, provide
means such as switches for powering off each of the external power supply and
external devices connected to the module to be replaced online.
(3) After the module has failed, data may not be saved properly. Referring to
Section 3.4.23, therefore, prerecord the data to be saved (offset/gain values of
the industrial shipment settings and user range settings in the buffer memory).
(4) It is recommended to perform an online module change in the actual system in
advance to ensure that it would not affect the other modules by checking the
following:
• Means of cutting off the connection to external devices and its configuration
are correct.
• Switching ON/OFF does not bring any undesirable effect.
(5) Do not install/remove the module to/from the base unit, or the terminal block
to/from the module more than 50 times after the first use of the product. (IEC
61131-2 compliant)
Failure to do so may cause malfunction.
(Note)
The dedicated instruction cannot be executed during an online module change. When
using the dedicated instruction to execute save/restoration, therefore, execute
save/restoration in the other system
1
.
If the other system is unavailable, execute restoration by performing write to the buffer
memory.
1 : If the module is mounted on the remote I/O station, execute save/restoration in
the other system mounted on the main base unit. (Save/restoration cannot be
executed in the other system mounted on the remote I/O station.)
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