Meta Datapoint : Abort instead of returning a value
I would like to know if it is possible to abort a Meta Datapoint script before creating its instance.
Let's suppose that :
- Raw data are acquire from remote sites
- Final value 'Meta Datapoints) are calculated using Raw data value.
- I would like to eliminate duplicate datapoints that have same value and same timestamp.
Would it be possible to check first the timestamp against previous value timestamp and if equal discard calculation WITHOUT creating an instance of the resultiong Meta Datapoint ?
what you want for Abort return a value?
if this case is right: same Raw data with calculation result is same, you no need abort,just let it calculation ,and you just set the point log on_change is ok,same value don't save until value is change
I have the same question. I want to check on an interval but only record a new value if the value of the field point has actually been updated. I don't want to record a value if communication has been lost to the field point over the interval period.
We use SQL data sources and then Meta Sources to scale the raw data into meaningful data. To avoid Mango creating data points while communication was lost from the data logger we have Mango set to read on a timestamp change only.
On the SQL data source we have a data point just for the timestamp, the other data points use a time override column name and on the meta source we use the timestamp data point for the context update.
Of course this will only work if your logging device creates its own timestamp or your SQL database records the date and time of the data insertion into the table.
I hope this helps
I also think that you just need to edit your point template and set Logging to "when point value changes". I don't think there's anything else you would need to do.