The customer wants to have a binding, that transfer the value, but also wants to have backup set on the receiving variable in the TAC Xenta device.
TAC Xenta 280/300/401
Setting the Backup flag will make the variable written into the flash memory every time the value is written.
Doing this on a value that is regularly transferred will damage the flash memory, as it has to write all the time.
The Backup flag should not be set on variables that are written to on a regular basis.