# fpmi.system.invokeLater problem

**URL:** <https://forum.inductiveautomation.com/t/fpmi-system-invokelater-problem/1753>\
**Category:** Archived Topics\
**Created:** [April 14, 2010, 9:08am UTC](https://forum.inductiveautomation.com/t/fpmi-system-invokelater-problem/1753 "2010-04-14T09:08:32Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![skallepalli](https://avatars.discourse-cdn.com/v4/letter/s/54ee81/32.png) [@skallepalli](https://forum.inductiveautomation.com/u/skallepalli)\
**Post date:** [April 14, 2010, 9:08am UTC](https://forum.inductiveautomation.com/t/fpmi-system-invokelater-problem/1753/1 "2010-04-14T09:08:32Z")

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Hi,

We are using ‘fpmi.system.invokeLater()’ function in propertyChange event of table Component on our window. We set this Window ‘Open on Startup’ (since, we want to show the window first).

When We log out from the Project We are getting the following error:

`Traceback (innermost last):
  File "<event:propertyChange>", line 11, in runLater
ValueError: No session found. You must re-login.
`

How can we resolve this problem ?

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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:** [April 14, 2010, 3:59pm UTC](https://forum.inductiveautomation.com/t/fpmi-system-invokelater-problem/1753/2 "2010-04-14T15:59:46Z")

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You can add a try block around your code inside the function:

`def doLater(event=event):
  import fpmi
  try:
    do something
  except:
    pass # no op
`  
Try this out.

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**Author:** ![Carl.Gould](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/carl.gould/32/7262_2.png) [@Carl.Gould](https://forum.inductiveautomation.com/u/Carl.Gould)\
**Post date:** [April 14, 2010, 4:33pm UTC](https://forum.inductiveautomation.com/t/fpmi-system-invokelater-problem/1753/3 "2010-04-14T16:33:33Z")

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What does the property change script do? I suspect you’re not protecting your property change script to only handle a single property correctly.

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<div class="post-metadata">

**Author:** ![skallepalli](https://avatars.discourse-cdn.com/v4/letter/s/54ee81/32.png) [@skallepalli](https://forum.inductiveautomation.com/u/skallepalli)\
**Post date:** [April 16, 2010, 7:05am UTC](https://forum.inductiveautomation.com/t/fpmi-system-invokelater-problem/1753/4 "2010-04-16T07:05:47Z")

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Actually, we are trying to get OPC Tag values in Table Component.

Travis, After using try block also We are getting same problem on project logout. I think the problem is related to Sessions.

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**Author:** ![Carl.Gould](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/carl.gould/32/7262_2.png) [@Carl.Gould](https://forum.inductiveautomation.com/u/Carl.Gould)\
**Post date:** [April 16, 2010, 4:21pm UTC](https://forum.inductiveautomation.com/t/fpmi-system-invokelater-problem/1753/5 "2010-04-16T16:21:36Z")

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Yes the problem is due to sessions. You’ve logged out - you don’t have a session, and yet you’ve told the system to do something “later”. You can’t do that, it will fail because you are no longer logged in.

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**Author:** ![skallepalli](https://avatars.discourse-cdn.com/v4/letter/s/54ee81/32.png) [@skallepalli](https://forum.inductiveautomation.com/u/skallepalli)\
**Post date:** [April 17, 2010, 11:43am UTC](https://forum.inductiveautomation.com/t/fpmi-system-invokelater-problem/1753/6 "2010-04-17T11:43:54Z")

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Thank you Carl