The reason for a tag being unknown by the I/O or alarm system may not be that it does not exist, just that the server it is on is yet to come up and tell us about it.
However, more often that not, it is because it does not exist. An out-of-range value has been passed to a function, or an array index is off the end of an array, or a value that is outside of the specified engineering scale has been assigned to a I/O Device variable.
Simply double-click the downloaded file to install it.
The information below should be reviewed and is not version specific.
The previous settings can be migrated to the new version by replacing the new configuration [INI] file with the previous version of the INI file.
When doing this, the following parameters would then need to be updated / added to reflect the new installation settings in the previous configuration file.
Citect, on the other hand, is designed to run with most PLCs on the market.
To run with Siemens PLCs, you need to purchase a separate driver.