Hourly CSV to historian

Ignition
1

Continuing my energy metering project …

Some of my energy meters upload CSV files by FTP to my server. The tables are in narrow format so I did a little testing and can get Python to open and parse the files.

ExportID               Date                  Value
Temperature T1         2017-02-25T23:15:00   36.3
Temperature T2         2017-02-25T23:15:00   36.2
Meter1 kWh             2017-02-25T23:15:00   175814
Meter2 kWh             2017-02-25T23:15:00   3221679

Q1. Am I correct in using system.tag.storeTagHistory to allow me to write both t_stamp and tag value?
Q2. How do I prevent double entries if a CSV file is parsed twice (during development or after a fault).
Q3. How should I run the script as a scheduled task, say, once an hour? Should I create a scheduled task / cron to run a client and have the client exit when complete?

Any ideas to prevent me going off on a difficult path would be very welcome.

2
  1. If you ultimately want this data to go into Ignition’s tag historian and be retrieved on, for instance, Easy Charts, then you can use system.tag.storeTagHistory - although this function is not guaranteed to scale well.
  2. If it’s on an FTP server, then I would just get it off the server, then upload it back with a different filename or extension to indicate that it’s been entered in.
  3. A scheduled task could be a gateway timer script that evaluates, say, every 60s (and checks if it’s the top of the hour before continuing execution) or you could use a transaction group on a schedule to flip a boolean tag, then a tag event script on that tag to fire the actual script. Either of these would be much, much better in terms of performance than trying to launch a client.