It is not clear what you are trying to do. Is it for another device you want to connect which is not a Modbus device? Then the advise would be: do not do that. It could give conflicts with the standard Modbus communication. But if it is a Modbus device, then why not use the standard Modbus device configuration?
Check the CODESYSControl.cfg. Here you can specify where the log output is written to, so you can also let it write to file. Please regard the numbering, because it should be kept in order (0, 1, 2, etc). Below a part which is copied from a .cfg file of the Control Win Runtime. This probably will look much the same on your controller. [CmpLog] Logger.0.Name=PlcLog ;Logger.0.Filter=0xFFFFFFFF Logger.0.Enable=1 Logger.0.MaxEntries=100000 Logger.0.MaxFileSize=500000 Logger.0.MaxFiles=3 Logger.0.Backend.0.ClassId=0x0000010B...
You opened it probably with SP18. Then I would suggest to close CODESYS, start the CODESYS Installer, update the Visualization add-on to 126.96.36.199 (or later). Then open the project again in SP18 and set the Visualization Profile to this version (Project - Project settings - Visualization profile).
Since SP17, you can start the CODESYS installer through the Windows menu. There you can find a list of add-ons. So you will have 3.5 SP17 installed as "essential version". In the CODESYS installer you can find the add-ons (for each installation) with its versions which you have installed. There you have the option to update the "Visualization" to a new version (latest currently is 188.8.131.52).