It has been some time ago since I implemented this.
Now I see a weird reaction to the "No-Data" writing into a future data tag. The following is the situation in which I write "No-Data":
For a customer we write a perfect batch trend into the future.
To make sure we see exactly when a batch should start/stops, we write a "No-Data" at the end of each perfect batch planning.
In other words, when a batch starts, we write an x amount of data into the future ending with a "no-data" value.
Now, the No-Data stay's fine, until the next batch starts and a new perfect batch planning is written into the future.
When this happens, we get an interpolated value instead of a broken up line in a trend.
Also, the No-Data has disappeared in the archive!
Anyone know how this is possible? Is a no-data in the future replaced with the next data written to it after the no-data timestamp?