What I did :
I have created an UDT (with many tags) for an electrical meter, UDT instances are created by passing a “meternumber” parameter.
In the Tag browser there is now a folder EM, with about 100 meter instances, with each instance about 50 tags.
The tagpath for tag “Kwh” from meternumber 50 for instance = EM/M50/Kwh
All tags are coming in OK and we want to save some variables to database for calculating the power consumption.
I used for this a block transaction group :
created a “block item” “meternumber”, therein 100 items (tagpaths) with use of pattern EM/M{?}/meternumber
created a block item “kWHTotal”, therein 100 items (tagpaths) with use of pattern EM/M{?}/KwhTotal
and scheduled the transaction group every 15 minutes.
This works, every 15 minutes there is now for every meter 1 record saved with fields
Timestamp,meternumber,KwhTotal
Is it possible to setup this block transaction group so that there will be saved one extra field “power consumption” in above record.
( = the calculated power consumption from the last 15 minutes for the meter.)
I can add 4 possible items to a transaction group ( OPC / block / expression / tag ),
they all seem to add an extra column to the database record (when you click the blockview tab).
But only in the block item it’s possible to add rows ( 1 for every meter)
Can’t find out how to add an extra calculated field in the database record for every meter with this block transaction setup.