Specifications

Changing running programs <Online program change> Frequently-used functions
MELSEC-L Series Quick start guide 3 - 17
3.4 Changing running programs <Online program change>
This function writes only the modified ladder block to the CPU module while the CPU module is in the
"RUN" status. A program can be written in a short time since this function does not transfer the whole
program.
The following is an example of adding a contact to the ladder.
Operating procedure
 Display the ladder.
 Add contacts
.
 Select Compile  Online Program Change.
 Click the Yes button.
When the online program change has been properly completed, the following message is displayed.
 Click the OK button.
Fig. 3-35:
Display ladder block to be changed
000075a
Fig. 3-36:
Add contacts
000076a
Fig. 3-37:
Confirm online program change message
000077a
Fig. 3-38:
Online program change completion
message
000078a
NOTE The program in the CPU module and the program to be modified in GX Works2 must be the same
to perform the online program change. If you are not sure, verify the programs in advance or mod-
ify the ladder after performing the "Read from PLC" function.
The ladder block is displayed in gray.
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