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Appendix 4 Online Module Change Procedure (When
Using GX Developer)
This appendix describes the online module change procedure using GX Developer.
Before performing an online module change, carefully read the following.
QCPU User's Manual (Hardware Design, Maintenance and Inspection)
Appendix 4.1 Precautions on online module change
Precautions on an online module change are listed below.
• When an online module change is performed, not all set values are inherited by the module after the change.
After the online module change, write the set values in the changed module again.
• When an online module change is performed, properly follow the procedure. ( Page 391, Appendix 4.4)
Not doing so may cause malfunction and failure.
• Before performing an online module change, check that the system outside of the programmable controller
does not malfunction.
• Prepare methods, such as a switch, that disconnect individually the external power supply for the module to
be changed online and the power supply for external devices to prevent electric shock and malfunction of the
module during transportation.
• Record the content to save (data of the writable buffer memory ( Page 387, Appendix 4.2 (5)))
beforehand, because the buffer memory data may not be saved normally in the event that the module
malfunctions.
• Even if pre-recorded data are set to the buffer memory in the module that was changed online and control is
restarted, the following areas are cleared when control is stopped. Therefore, control cannot be restarted in
the same control status.
• Even if an alert occurs before performing an online module change, the same alert does not necessarily
occur when the control is restarted. For example, if an upper limit alert with standby is set and the alert
occurs before performing an online module change, the module goes into the standby status and the alert
does not occur when the control is restarted after performing the online module change.
• To check the following items, it is recommended to perform the online module change on the actual system
and verify that the operation of modules not to be changed is not affected.
• After the first use of the product, do not mount/remove the module to/from the base unit, and the terminal
block to/from the module more than 50 times (IEC 61131-2 compliant) respectively.
Exceeding the limit may cause malfunction.
•CH Manipulated value (MV) (Un\G13 to Un\G16)
•CH Manipulated value for heating (MVh) (Un\G13 to Un\G16)
•CH Manipulated value for cooling (MVc) (Un\G704 to Un\G707)
• The method and configuration to disconnect the connection with external devices are correct.
• Turning off, on, and off the switch has no influence.