# Tag Historical "On Change" Mode Not Working

**URL:** <https://forum.inductiveautomation.com/t/tag-historical-on-change-mode-not-working/64151>\
**Category:** Ignition\
**Tags:** ignition81, database, perspective\
**Created:** [September 16, 2022, 8:24am UTC](https://forum.inductiveautomation.com/t/tag-historical-on-change-mode-not-working/64151 "2022-09-16T08:24:54Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Shaheryar\_Ahmad](https://avatars.discourse-cdn.com/v4/letter/s/f6c823/32.png) [@Shaheryar\_Ahmad](https://forum.inductiveautomation.com/u/Shaheryar_Ahmad)\
**Post date:** [September 16, 2022, 8:24am UTC](https://forum.inductiveautomation.com/t/tag-historical-on-change-mode-not-working/64151/1 "2022-09-16T08:24:54Z")

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Dear All,  
Hope you are doing well

Please consider my below query and guide me on this.

**My Task:**  
Reading VFD operational Data over Modbus

**Ignition Version:**  
8.1 and Paid License

**Issue Facing:**

**1.)** On the analog nature tag (like Current, Voltage, Frequency etc) enabled the “Tag History” option, when I am setting the Sampling Mode to “ **On Change** ”, no values are logging in the database. Even I changed the Minimum Sampling time and Deadband values. _The values are only logged, when the Maximum Sampling time has past, like I set it to 1 minute/1 hr._

**What I have observed that, the logging is happening but the ‘time of logging’ is quite weird it is of year 1969 _(see in picture 1 below)_**

 ![MicrosoftTeams-image (5)](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/2/a2b102434ae50406f93a640692fa77051aea74dd.jpeg)

**2.)** When I am setting the Sampling Mode to “ **Periodic** ” and set the sampling time to 1 sec, Values are still not logged in the database after every 1 sec _(like it should a/c to periodic definition)_, but they are only logged whenever the values are changed. It is behaving like the ‘On Change’ mode.

Here the logging time is correct _(see in picture 2 below)_

 ![MicrosoftTeams-image (6)](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/4/a46cb0d8fef7c23cd5f66191cfdd11a3c8e05f81.jpeg)

I have already done the restarting of ‘Tag History’ module but no success.

Please guide me in this, as this project is stuck because of this issue… I have to use the power chart for the operational data trending, but facing this logging issue.

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**Author:** ![j.israelsen](https://avatars.discourse-cdn.com/v4/letter/j/ad7895/32.png) [@j.israelsen](https://forum.inductiveautomation.com/u/j.israelsen)\
**Post date:** [September 16, 2022, 2:02pm UTC](https://forum.inductiveautomation.com/t/tag-historical-on-change-mode-not-working/64151/2 "2022-09-16T14:02:11Z")

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Very interesting, I have the following thoughts:

1. Looks like you did a bunch of good review of your “History” settings. Have you double checked things like your tag “Numeric” settings? Specifically the deadband settings.

2. If the previous doesn’t help out: Based on the information you presented it does seem odd on the behavior between “Periodic” and “On Change”. Perhaps you need to run this question by support?

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**Author:** ![jlandwerlen](https://avatars.discourse-cdn.com/v4/letter/j/bc8723/32.png) [@jlandwerlen](https://forum.inductiveautomation.com/u/jlandwerlen)\
**Post date:** [September 16, 2022, 2:24pm UTC](https://forum.inductiveautomation.com/t/tag-historical-on-change-mode-not-working/64151/3 "2022-09-16T14:24:11Z")

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Your other post answered the issue on min vs max time between samples, it looks like you are getting the definitions reversed.

> [@Tags Historical logging Sampling rate Issue](https://forum.inductiveautomation.com/t/tags-historical-logging-sampling-rate-issue/64075):
>
> Dear All, Hope you all are doing well. I am facing a very weird issue when using the tag history feature in Ignition 8.1 perspective. When, I enable historical logging in a tag (float datatype) and do the configuration i.e. make the the sampling mode “On Change”, Minimum Sampling Time 1 sec and Maximum Sampling time 3 Hr (picture below). After doing this, when the tag starts running and getting different values in it, no values are logged in the database and on Power Chart the trend of that t…

To add, perhaps the docs will help, [Configuring Tag History - Ignition User Manual 8.1 - Ignition Documentation](https://docs.inductiveautomation.com/display/DOC81/Configuring+Tag+History)