All PLC I/O and devices can be commented in GX Developer and down loaded to the PLC however there are a maximum number of characters.
When programming an FX PLC with GX Developer it is possible to comment all I/O and devices. These comments can be stored within the PLC but there is a difference between what the software supports and what the PLC supports as detailed below.
The example GX Developer line of code shows 2 I/O points that have been commented.
These comments use the default setting of 4 lines of 8 characters however, the PLC only supports a maximum of 16 characters. If comments are stored into the PLC and then uploaded at some later date, the PLC will only return the first 16 characters as shown below.
The solution to this is to either stick to 2 lines of 8 characters or set the comment format to the old Medoc software equivalent format of 3 lines of 5 characters. As shown below:
For further information, refer to the appropriate PLC instruction manual and the GX Developer help files.