# Unable to read TCP Modbus String Tag Value

**URL:** <https://forum.inductiveautomation.com/t/unable-to-read-tcp-modbus-string-tag-value/113749>\
**Category:** Ignition\
**Tags:** vision\
**Created:** [February 4, 2026, 7:06am UTC](https://forum.inductiveautomation.com/t/unable-to-read-tcp-modbus-string-tag-value/113749 "2026-02-04T07:06:38Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![bhavanap](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@bhavanap](https://forum.inductiveautomation.com/u/bhavanap)\
**Post date:** [February 4, 2026, 7:06am UTC](https://forum.inductiveautomation.com/t/unable-to-read-tcp-modbus-string-tag-value/113749/1 "2026-02-04T07:06:39Z")

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I have a string tag in Holding Register with Address 20. The array length is 16. I need to map the OPC Path of this tag in designer. I have tried the following mappings:

1. ns=1;s=[Riedhammer Kiln]1.HRS20:16 - Qualtiy good, Value empty str
2. ns=1;s=[Riedhammer Kiln]1.HRS20:15 - Qualtiy good, Value empty str
3. ns=1;s=[Riedhammer Kiln].HRS20:15 / 16 - Qualtiy good, Value empty str
4. ns=1;s=[Riedhammer Kiln]1.HRS19:15 / 16 - Qualtiy good, Value - Some Symbol shown in ss
5. ns=1;s=[Riedhammer Kiln]1.HRS21:15 / 16 - Qualtiy good, Value “.26m m\ni”

What am I doing wrong?

 ![Screenshot 2026-02-04 123601](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/e/9e81412b88ce4ee02c7d0d612949dba3355751d3.jpeg)

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**Author:** ![David\_Stone](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/david_stone/32/79749_2.png) [@David\_Stone](https://forum.inductiveautomation.com/u/David_Stone)\
**Post date:** [February 4, 2026, 7:33am UTC](https://forum.inductiveautomation.com/t/unable-to-read-tcp-modbus-string-tag-value/113749/2 "2026-02-04T07:33:42Z")

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A string and an array are very different structures.  
Can you show us the PLC data block where the string is defined?

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<div class="post-metadata">

**Author:** ![David\_Stone](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/david_stone/32/79749_2.png) [@David\_Stone](https://forum.inductiveautomation.com/u/David_Stone)\
**Post date:** [February 4, 2026, 7:38am UTC](https://forum.inductiveautomation.com/t/unable-to-read-tcp-modbus-string-tag-value/113749/3 "2026-02-04T07:38:12Z")

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> [@bhavanap](#):
>
> .26m m\ni

Is this part of your string?

`.62 m/min`

If so, you need to tick "Reverse String Byte Order" in the device settings and probably also tick "Zero-based Addressing" and reference the following address:

`ns=1;s=[Riedhammer Kiln]1.HRS20:16`

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<div class="post-metadata">

**Author:** ![bhavanap](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@bhavanap](https://forum.inductiveautomation.com/u/bhavanap)\
**Post date:** [February 4, 2026, 8:08am UTC](https://forum.inductiveautomation.com/t/unable-to-read-tcp-modbus-string-tag-value/113749/4 "2026-02-04T08:08:09Z")

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Actually we have been only provided an excel sheet of addresses as follows:

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/3/3/331ba045a0584884ff86cce95a5ff0fb8f5d6bf8.png)