# UDT Alarm Deadband

**URL:** <https://forum.inductiveautomation.com/t/udt-alarm-deadband/6700>\
**Category:** Ignition\
**Created:** [June 13, 2013, 2:10am UTC](https://forum.inductiveautomation.com/t/udt-alarm-deadband/6700 "2013-06-13T02:10:52Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![gadgetguru69](https://avatars.discourse-cdn.com/v4/letter/g/e274bd/32.png) [@gadgetguru69](https://forum.inductiveautomation.com/u/gadgetguru69)\
**Post date:** [June 13, 2013, 2:10am UTC](https://forum.inductiveautomation.com/t/udt-alarm-deadband/6700/1 "2013-06-13T02:10:52Z")

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Can someone else please verify that they are seeing the same issue with the Alarm deadband inside a UDT. What I am seeing is that when I try to set the alarm deadband to a UDT tag it causes all of the tags in the UDT to go to a unknown state. I have attached the UDT there is only one value that has an alarm at this point that is the Value\_in tag. this UDT does not have the deadband for this tags alarm set in it.  
We are running 7.6.2.rc1

Any thoughts?  
[RTDUDT.xml](https://us1.discourse-cdn.com/inductiveautomation/original/2X/3/39fe799aca8a4bfa67c5a93c12e7160a19969669.xml) (19.5 KB)

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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:** [July 1, 2013, 10:51pm UTC](https://forum.inductiveautomation.com/t/udt-alarm-deadband/6700/2 "2013-07-01T22:51:03Z")

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Hi,

I’m not seeing this. Is it still happening? Since that UDT uses many OPC items that I don’t have, the best I can do is mock up a similar structure, and I’m not running into a problem.

If the values are going to “unknown”, my best guess is that perhaps an error is occurring on initializing the instance, and it’s ending up in some half-started state. Is there anything in the gateway console? If you disable and re-enable the instance, the error should happen again.

Regards,

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**Author:** ![gadgetguru69](https://avatars.discourse-cdn.com/v4/letter/g/e274bd/32.png) [@gadgetguru69](https://forum.inductiveautomation.com/u/gadgetguru69)\
**Post date:** [July 2, 2013, 10:57am UTC](https://forum.inductiveautomation.com/t/udt-alarm-deadband/6700/3 "2013-07-02T10:57:00Z")

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Colby  
I have attached a test UDT that you can use it does the same thing pointing to the simulator so you should be able to see what I am talking about. If you simple remove the binding from the alarm deadband all is well. running 7.6.2 rc5  
[testUDT.xml](https://us1.discourse-cdn.com/inductiveautomation/original/2X/5/5437e84d2a516ddbe76481d75a053a845ac1f91d.xml) (1.16 KB)

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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:** [July 2, 2013, 5:14pm UTC](https://forum.inductiveautomation.com/t/udt-alarm-deadband/6700/4 "2013-07-02T17:14:58Z")

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Thanks, I’ve tracked it down. When the tag is initialized, the first referenced opc value hasn’t come in yet, and so the value is null, causing a problem on the alarm init. It has been fixed for 7.6.3. If you need a workaround, bind it to an expression instead:

```auto
coalesce({TagRef},0.0)
```

Regards,

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**Author:** ![gadgetguru69](https://avatars.discourse-cdn.com/v4/letter/g/e274bd/32.png) [@gadgetguru69](https://forum.inductiveautomation.com/u/gadgetguru69)\
**Post date:** [July 2, 2013, 7:06pm UTC](https://forum.inductiveautomation.com/t/udt-alarm-deadband/6700/5 "2013-07-02T19:06:36Z")

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Great Thanks Colby