# Modbus TCP Uncertain\_InitialValue

**URL:** <https://forum.inductiveautomation.com/t/modbus-tcp-uncertain-initialvalue/41057>\
**Category:** Ignition\
**Created:** [November 30, 2020, 5:58pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-uncertain-initialvalue/41057 "2020-11-30T17:58:09Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![alicia](https://avatars.discourse-cdn.com/v4/letter/a/ecd19e/32.png) [@alicia](https://forum.inductiveautomation.com/u/alicia)\
**Post date:** [November 30, 2020, 5:58pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-uncertain-initialvalue/41057/1 "2020-11-30T17:58:09Z")

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![ModbusSubscription](https://us1.discourse-cdn.com/inductiveautomation/original/3X/1/3/1368005455f203c66fe98401a7bf1638b8d21697.png)

I’m using a Moxa E1240 remote IO device. I had values coming in, but now they’re saying uncertain\_InitialValue when I subscribe and in the tag that I created. However, if I read from quick client there are good values. Does anyone have any idea how to resolve?

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**Author:** ![Matrix\_Engineering](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/matrix_engineering/32/19781_2.png) [@Matrix\_Engineering](https://forum.inductiveautomation.com/u/Matrix_Engineering)\
**Post date:** [November 30, 2020, 6:07pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-uncertain-initialvalue/41057/2 "2020-11-30T18:07:45Z")

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[![](https://us1.discourse-cdn.com/inductiveautomation/original/3X/2/8/288d9e10aeb71d1d8d0a81b8d0f3ef8265010e60.jpeg "ModBusTCP Moxa E1240 Ignition SCADA") ](https://www.youtube.com/watch?v=RDcFgat6_sc)

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**Author:** ![Matrix\_Engineering](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/matrix_engineering/32/19781_2.png) [@Matrix\_Engineering](https://forum.inductiveautomation.com/u/Matrix_Engineering)\
**Post date:** [November 30, 2020, 6:08pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-uncertain-initialvalue/41057/3 "2020-11-30T18:08:28Z")

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And welcome to the forum 🙂

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**Author:** ![alicia](https://avatars.discourse-cdn.com/v4/letter/a/ecd19e/32.png) [@alicia](https://forum.inductiveautomation.com/u/alicia)\
**Post date:** [November 30, 2020, 6:39pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-uncertain-initialvalue/41057/4 "2020-11-30T18:39:06Z")

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I used this video to get it going, but then ran into the uncertain initial value issue. Any ideas why my tags are doing that and how to recover? Thanks for the video by the way.

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**Author:** ![Matrix\_Engineering](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/matrix_engineering/32/19781_2.png) [@Matrix\_Engineering](https://forum.inductiveautomation.com/u/Matrix_Engineering)\
**Post date:** [November 30, 2020, 6:47pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-uncertain-initialvalue/41057/5 "2020-11-30T18:47:00Z")

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I have an E1240 here in the office, send me an export from the gateway of the tag setup, and also a tag export from designer.

Also, you can go to status (in the gateway), click the device, and look at the info (change the min level to trace).

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**Author:** ![alicia](https://avatars.discourse-cdn.com/v4/letter/a/ecd19e/32.png) [@alicia](https://forum.inductiveautomation.com/u/alicia)\
**Post date:** [November 30, 2020, 7:37pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-uncertain-initialvalue/41057/6 "2020-11-30T19:37:25Z")

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I’m trying a gateway reboot. It’s something with the subscription datamode. It works with polling.

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<div class="post-metadata">

**Author:** ![alicia](https://avatars.discourse-cdn.com/v4/letter/a/ecd19e/32.png) [@alicia](https://forum.inductiveautomation.com/u/alicia)\
**Post date:** [November 30, 2020, 7:44pm UTC](https://forum.inductiveautomation.com/t/modbus-tcp-uncertain-initialvalue/41057/7 "2020-11-30T19:44:12Z")

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Reboot of gateway resolved. Alternatively, by using polling, which isn’t ideal was a good work around.