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You are on
the right road. Historical Log
Configuration is designed exactly for what you are trying to do, i.e. Create a
Batch Log File with historical data that is associated with a particular production
run.
Apart from usual
list of variables and common scan rate, the option also allows a start trigger variable
and condition to be configured. PACDisplay
will then scan the variable (at the same rate at a specified scan group rate,
note it doesn’t have to be the same as the common scan rate) and check the
condition. For digital values this can
be ON or OFF, while analog values can be checked for >, >=, <, <=
or =. Once the condition is met data
will start being written to the file.
The next
decision is when to stop writing to the file, through configuration of the Stop
Trigger. Once again a variable and
condition can be specified. Alternatively
the file can be left open until a specified number of samples have been
collected.
The files
produced are basically logging files, so follow the usual rules of specifying a
rollover period, filename, save directory and file cleanup. I would suggest you configure the rollover
period from “Days” to “None”, You will
need to judge how much data this will create in a single file, and also be
responsible for file cleanup and deleting old files, but these files will not rollover.
I think the one trick you are missing is the
use of a strategy sourced file name. Normally
the automatically generated rollover files use an MSDOS automatic file name specifiying
type of file (H) the file ID, and rollover date. To save data related to a specific batch, I
would suggest you to use the “From Strategy” option for the filename. In this scenario, by preparing the BatchID as
an Opto String Variable and having this available before starting logging, the data
files will be saved as production files associated with the BatchID and not just the typical time based format.
This is a feature that is sadly missing on
many SCADA and DCS systems costing thousands of dollars. Some sell the “feature” as a separate package
(also costing several thousand dollars), just to relate normal historical data
to specific production runs. I once worked with a DCS that required a special hardware costing UD$20,000 and a special software licence that cost UD$5,000 and a lot of required "DoItYourself" software programming to do just that. (Those were the days, before the world got warmer). Needless to say the customer had no idea that he would have to pay this when he initially selected and bought the system. With Opto22,
its all included in the price, which in the case of PAC Project Basic is less
than one cent.
Opto22 doesn't market PACProject as a specific Batch production software, but if you take time to study it, you will find it contains as standard, many of the features touted by specific phamaceutical and FDA orientated software packages. Its just that other companys employ more monkeys to bang the drum! You may also like to checkout operator action logging, file encryptation and user access control, recipe downloading and uploading, iust for starters.
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