Adding multiple historical data together

Ignition
1

I was trying to add some historical data of the flows to calculate total flow. I know total flow is calculated by adding each flow at a time. How do I add them so that I get the historical data of total flow so that I can display it in report? Thanks

2
  1. Where is it stored?
  2. In what units is it stored (flowrate (L/s), flow volume (litres), etc.)?
3

The easiest way might be to add an historized expression tag that sums up your partial flows.

4

All the flows are stored in Tag Historical Provider. The flowrate unit is same for all flows. I just need to add the flows and the total flowrate will also be same unit.

5

I did that. I created new expression tag and added all the flows together but it wont show/add the data from the past. It only shows the data from the time I configured tag history to the new totalflow tag.

6

The flowrate unit is same for all flows. I just need to add the flows and the total flowrate will also be same unit.

You can't total flowrates. 5 L/minute for one minute and 3 L/minute for another minute doesn't give you 8 L/minute. You can average them though.
You can total flows. This would be L (litres) or whatever your units are.

  1. Is the flow data cumulative (e.g. 10, 12, 14, 16, ...) or incremental (e.g., 2, 2.1, 2, 1.9, etc.).
7

If you need data from before, you can use queryTagHistory and do the calculations yourself:

tags = system.tag.queryTagHistory(paths)
tags = system.dataset.toPyDataSet(tags)
total_flow = [
	{
		'timestamp': row[0],
		'value': sum(row[1:])
	} for row in tags
]

If the presence of None is possible in your data, you can use this instead, but you might not get the results you want:

total_flow = [
	{
		'timestamp': row[0],
		'value': reduce(lambda x, y: (x or 0) + (y or 0), row[1:])
	} for row in tags
]
8

I meant to add flowrate at certain time for different flowmeters. Lets say for two flowmeters, if one is 5 and other is 3 during that time, I can add it to 8 units as the total flow during that time. I want to do that for multiple flowmeters.

9

Thanks, I will try to use this and see if I can do it.

Another way I am trying is to import each flow in the report and add them together in a column and export the total value in excel. Since I just need a report of this flow, that should do it.
I am also thinking of creating a database table with all the flows and a new column with their sum just in case for the future.