EasyChart issue with exported data

Hello, IA.

One user recently reported that he was detecting two different readings “recorded” at the same t_stamp, and those could vary between a few degrees up to “a few hundred”.

This is the set up: Ignition 8.0.13, EasyChart component, Historical data for one tag, Min/Max aggregation mode.

I have exported the Chart data for periods of 2, 24, 48, and 72 hours, as well as 1, 2, 3, and 4 weeks.

And on the 48-hour data export I detect the first occurrence of this issue where we are getting two different readings at the same time stamp; additionally the difference between values worsens from a difference of 80 degrees on the 48-hour data sample, to 550 degrees on the 1-month data.

These are the worst examples I could find:

48 hours:

t_stamp floatvalue
2021-03-07 07:15:22 155
2021-03-07 07:15:22 75.30000305

1 month:

t_stamp floatvalue
2021-03-13 06:53:24 381.2999878
2021-03-13 06:53:24 931

Raw data is about 7,000 rows, which is crunched down into just 600 rows from the EasyChart’s Save button.

I understand that MinMax “will return two entries per time slice - the min and the max.” But there must be something really wrong with whatever method you’re using because our furnaces are incapable of increasing the temperature by more than 550 degrees in less than 1 second.