# Scanclass and deadband : modifiy in live

**URL:** <https://forum.inductiveautomation.com/t/scanclass-and-deadband-modifiy-in-live/2551>\
**Category:** Ignition\
**Created:** [January 25, 2011, 9:36pm UTC](https://forum.inductiveautomation.com/t/scanclass-and-deadband-modifiy-in-live/2551 "2011-01-25T21:36:58Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![gnguyen](https://avatars.discourse-cdn.com/v4/letter/g/41988e/32.png) [@gnguyen](https://forum.inductiveautomation.com/u/gnguyen)\
**Post date:** [January 25, 2011, 9:36pm UTC](https://forum.inductiveautomation.com/t/scanclass-and-deadband-modifiy-in-live/2551/1 "2011-01-25T21:36:58Z")

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Hello,

Is it possible to modify the scanclass and or the deadband of an SLQTags in realtime ?

What we need to do is to change SC and/or DB for some SQLTags when the user want to have a deeper look at some special events.

Thanks for your help

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**Author:** ![Travis.Cox](https://avatars.discourse-cdn.com/v4/letter/t/b9bd4f/32.png) [@Travis.Cox](https://forum.inductiveautomation.com/u/Travis.Cox)\
**Post date:** [January 25, 2011, 9:57pm UTC](https://forum.inductiveautomation.com/t/scanclass-and-deadband-modifiy-in-live/2551/2 "2011-01-25T21:57:31Z")

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Not if the tag provider is internal. If the tag provider is a database driving provider you can since the tags are stored in the SQL database.

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**Author:** ![Colby.Clegg](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/colby.clegg/32/3282_2.png) [@Colby.Clegg](https://forum.inductiveautomation.com/u/Colby.Clegg)\
**Post date:** [January 25, 2011, 10:01pm UTC](https://forum.inductiveautomation.com/t/scanclass-and-deadband-modifiy-in-live/2551/3 "2011-01-25T22:01:07Z")

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Hi,

There are a few different things you can try.

1. Driven Scanclasses - If the tags that you want to occasionally view more quickly can be organized into groups, the driven scan class lets you control the rate off of a trigger tag. There is a fast and a slow rate. The slow rate would be your normal rate, and then the fast would be whatever you wanted, and then you could trigger it off of a simple static db tag.

2. Write to the deadband property of the tag - it is possible to write to most properties of tags. You can use [tt]system.tag.writeToTag(“Path/To/Tag.Deadband”, 0.01)[/tt]  
This will change the deadband, but note that right now it will also cause the tag to reload. Not usually a big deal, but it will probably blink bad quality for a second. We can probably update this property to be a “runtime property” in the future, that is- one that can be updated without a reload.

Hope this helps,

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**Author:** ![gnguyen](https://avatars.discourse-cdn.com/v4/letter/g/41988e/32.png) [@gnguyen](https://forum.inductiveautomation.com/u/gnguyen)\
**Post date:** [January 25, 2011, 10:13pm UTC](https://forum.inductiveautomation.com/t/scanclass-and-deadband-modifiy-in-live/2551/4 "2011-01-25T22:13:29Z")

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Colby, Travis,

Nice. I’ll try this. I think having the SC as a “runtime property” should be a good new for us. I’ll try driven SC.

Another “plus” would be to have an “ante mortem”. In this case, some tags only are in the ante mortm list. When a fault occur, tags values are store for a short time : 30s before the event and 30s after (both should be parameters).

Regards,