I have a few Performance Counter DCIs, which will only collect data when a process is running.
When the process doesn't run, NetXMS will generate a collection error.
So far, so expected.

In this particular case, I'd like to be able to transform a data collection error into a value, i.e. 0. Main reason for this are graphs - the errors mean NetXMS will try to connect the dots between whenever instances when the process was running, which looks rather confusing and 0 is in fact accurate in this case. If a process is not running at all, then it is not utilising any CPU (or disk/memory).

But it looks as if a collection error means the transformation script is not even called (I added some trace commands, but nothing was ever logged)?
Not sure if it would be possible to allow sending such an error condition through to a transformation script to handle (without breaking the current process, i.e. if a transformation script doesn't handle this particular condition, it should still return the usual data collection error).

Cheers