Introduction
Many customers want to save comments (I/O Tag names) to an FX PLC but don’t know how to do it and what the implications are. This post aims to explain this issue.
Design Considerations
To be able to save comments (I/O Tag names) in the PLC such that they can subsequently be retrieved from the PLC the user must first make space in the PLC memory as follows. From the “Project data list” window on the left hand side, select “Parameter” and then “PLC Parameter”. When the Window appears as shown below, select the number of memory blocks (“Comment capacity”) required for the comments as shown.
NOTE: one block equals 500 steps of program space lost to comments.
To download comments, the following setting must be made during the download process as shown below.
NOTE: FX PLCs only support 2 lines of 8 characters or 3 lines of 5 characters for the comment format even though the default in the software is 4 lines of 8 characters.
Further Information
For further information please see the FX PLC programming manual.
