# itemsAdded breaks when scan class is modified

**URL:** <https://forum.inductiveautomation.com/t/itemsadded-breaks-when-scan-class-is-modified/7930>\
**Category:** Module Development\
**Created:** [January 31, 2014, 4:39pm UTC](https://forum.inductiveautomation.com/t/itemsadded-breaks-when-scan-class-is-modified/7930 "2014-01-31T16:39:29Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![lisawas](https://avatars.discourse-cdn.com/v4/letter/l/4bbf92/32.png) [@lisawas](https://forum.inductiveautomation.com/u/lisawas)\
**Post date:** [January 31, 2014, 4:39pm UTC](https://forum.inductiveautomation.com/t/itemsadded-breaks-when-scan-class-is-modified/7930/1 "2014-01-31T16:39:29Z")

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Working on the subscription logic of my driver, I ran into an oddity: when I modified my scan class to poll at 5 seconds instead of 4, itemsAdded appears to have been called to reregister my tag at 5ms. Here are the pertinent logs:

code 9:22:52 AM class com.amazon.lisawas.flexsortdriver.gateway.FlexsortDriver - RsShipping Subscribing //Diagnostics/Computer/FanRPM/CPU at rate of 5ms  
(D) 9:22:52 AM class com.amazon.lisawas.flexsortdriver.gateway.FlexsortDriver - RsShipping Unregistering Ignition subscription task.  
(T) 9:22:52 AM com.amazon.lisawas.flexsortdriver.gateway.subscriptions.SubscriptionHandler New Polling Cycle: []  
(D) 9:22:52 AM com.amazon.lisawas.flexsortdriver.gateway.subscriptions.SubscriptionHandler Updating polling cycle…  
(D) 9:22:52 AM class com.amazon.lisawas.flexsortdriver.gateway.FlexsortDriver - RsShipping Unsubscribing //Diagnostics/Computer/FanRPM/CPU at rate of 4000ms  
[WARN] 9:22:52 AM xopc.server.subscriptions.Subscription [Subscription ID: 1 Session name: UaClientSession\_1391179690454] received a requested for a publishing interval \<= 0. Using minimum.  
(I) 9:22:52 AM SQLTags.Manager Modifying scanclass ‘Default’ on ‘default’. New name: ‘Default’  
(D) 9:22:43 AM class com.amazon.lisawas.flexsortdriver.gateway.FlexsortDriver - RsShipping Registering Ignition subscription task with a polling rate of 4000[/code]

At this point, my device responded with a resounding 'No way." Is this a bug, or do I have to do something special when I modify a scan class?

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**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:** [January 31, 2014, 6:26pm UTC](https://forum.inductiveautomation.com/t/itemsadded-breaks-when-scan-class-is-modified/7930/2 "2014-01-31T18:26:49Z")

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I’m not seeing this. Are you sure you didn’t type ‘5’ instead of ‘5000’ into the scan class dialog?

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**Author:** ![lisawas](https://avatars.discourse-cdn.com/v4/letter/l/4bbf92/32.png) [@lisawas](https://forum.inductiveautomation.com/u/lisawas)\
**Post date:** [January 31, 2014, 7:07pm UTC](https://forum.inductiveautomation.com/t/itemsadded-breaks-when-scan-class-is-modified/7930/3 "2014-01-31T19:07:56Z")

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You’re right. It looks like I messed up. Sorry about that.