What transaction Group type to use for such purpose?

Ignition
1

Let’s say I have 2 tags val1 and val2, both initiated with value of 5. val1 changes value at 00:00 and again at 00:10, then val2 changes value at 00:20. I will then have this table at Database:

|time_stamp | val1 | val2|
|00:00 |5 |5 |
|00:10 |9 |5 |
|00:20 |9 |9 |

What kind of transaction group, and set up, should I use to have below table instead?

|time_stamp | val_index | value|
|00:00 |1 |5 |
|00:00 |2 |5 |
|00:10 |1 |9 |
|00:20 |2 |9 |

2

Use the regular tag historian instead of a transaction group. The tag historian uses “tall” format with tag IDs.

3

Thanks pturmel for the response. Transaction Group also offer feature to log multiple tags on value change of 1 (or more) tag. As far as i understand, Historian can only log tag based on its value change. Is there any work around to Historian based on other tag value change?

4

Your example of “tall” shows only one value being recorded for the latter changes. That is what the tag historian will do. A SQL Bridge transaction group logs multiple values together with a single timestamp. The two approaches are fundamentally different. Use each where you need them.