# Scan Classes Organization **URL:** \ **Category:** Ignition\ **Created:** [February 17, 2016, 11:48am UTC](https://forum.inductiveautomation.com/t/scan-classes-organization/11225 "2016-02-17T11:48:02Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Ignaciof](https://avatars.discourse-cdn.com/v4/letter/i/ecccb3/32.png) [@Ignaciof](https://forum.inductiveautomation.com/u/Ignaciof)\ **Post date:** [February 17, 2016, 11:48am UTC](https://forum.inductiveautomation.com/t/scan-classes-organization/11225/1 "2016-02-17T11:48:02Z")
Hola! I have a question about Tags organization in Scan Classes, is better englobe all the tags in two or three Scan Classes or make smaller groups? In my case, I have a big default Scan Classe and we realized that is having a little delay: And the configuration is: So the question is: should we divide it? or it must be a communication problem? ---
**Author:** ![Ignaciof](https://avatars.discourse-cdn.com/v4/letter/i/ecccb3/32.png) [@Ignaciof](https://forum.inductiveautomation.com/u/Ignaciof)\ **Post date:** [February 22, 2016, 7:47am UTC](https://forum.inductiveautomation.com/t/scan-classes-organization/11225/2 "2016-02-22T07:47:25Z")
Come on guys, for sure is not a difficult question for the Inductive Team! ---
**Author:** ![Ignaciof](https://avatars.discourse-cdn.com/v4/letter/i/ecccb3/32.png) [@Ignaciof](https://forum.inductiveautomation.com/u/Ignaciof)\ **Post date:** [February 26, 2016, 7:27am UTC](https://forum.inductiveautomation.com/t/scan-classes-organization/11225/3 "2016-02-26T07:27:08Z")
No one? ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [February 26, 2016, 1:00pm UTC](https://forum.inductiveautomation.com/t/scan-classes-organization/11225/4 "2016-02-26T13:00:43Z")
Considering the quantity of tags, I’d suspect you’ve simply exceeded the bandwidth of the PLC connections involved. The diagnostic pages of the PLC drivers will provide a great deal of information about this. You haven’t shared any driver information, so I have no specific advice. I can say that for some PLCs, driver advanced settings can make a big difference. Also consider making multiple simultaneous drivers for each PLC, splitting the tags in chunks between them. I would not expect splitting up the scan class to affect the performance, except possibly negatively in some pathological optimization cases. But adding leased scan classes can also help, by not having to scan some tags as often when your operators aren’t actively looking at them. The “Tags in Ignition” section of [Inductive University](https://inductiveuniversity.com/) explains how all of this works in some detail. ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [February 26, 2016, 2:10pm UTC](https://forum.inductiveautomation.com/t/scan-classes-organization/11225/5 "2016-02-26T14:10:28Z")
I would also move any query tags you have into separate scan classes as well. ---
**Author:** ![Ignaciof](https://avatars.discourse-cdn.com/v4/letter/i/ecccb3/32.png) [@Ignaciof](https://forum.inductiveautomation.com/u/Ignaciof)\ **Post date:** [March 2, 2016, 11:12am UTC](https://forum.inductiveautomation.com/t/scan-classes-organization/11225/6 "2016-03-02T11:12:16Z")
> [@pturmel](#): > > Also consider making multiple simultaneous drivers for each PLC, splitting the tags in chunks between them. [...] But adding leased scan classes can also help, by not having to scan some tags as often when your operators aren't actively looking at them. Ok, I'll try that. > [@Kevin.Herron](#): > > I would also move any query tags you have into separate scan classes as well. I did that at first, all query tags are in other scan class. Thanks both for the advices!