# Limitations demo version

**URL:** <https://forum.inductiveautomation.com/t/limitations-demo-version/3820>\
**Category:** General Discussion\
**Created:** [January 4, 2012, 3:35pm UTC](https://forum.inductiveautomation.com/t/limitations-demo-version/3820 "2012-01-04T15:35:42Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![merlijn](https://avatars.discourse-cdn.com/v4/letter/m/54ee81/32.png) [@merlijn](https://forum.inductiveautomation.com/u/merlijn)\
**Post date:** [January 4, 2012, 3:35pm UTC](https://forum.inductiveautomation.com/t/limitations-demo-version/3820/1 "2012-01-04T15:35:42Z")

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Im unable to write tags using modbus tcp devices on the OPC-UA Server  
Getting the error message:  
[color=#FF0000]“Error writing to MW\_WORD\_01.value: Gateway Comm Mode is not Read/Write.”[/color]

When I monitor the communication with the programm Wireshark I only see modbus read instructions and no write instructions

Can it be that this is caused by limitations in the demo version of Ignition  
As far as I can see I dont have a option to set a read or write option in the modbus-tcp driver

I Have put a Image of the error message as atachment

Does anybody experience the same problem  
 ![](https://us1.discourse-cdn.com/inductiveautomation/original/1X/0768e07845aa23826b6e37f0e548f443ff9c8638.jpg)

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**Author:** ![Greg.Buehler](https://avatars.discourse-cdn.com/v4/letter/g/ecc23a/32.png) [@Greg.Buehler](https://forum.inductiveautomation.com/u/Greg.Buehler)\
**Post date:** [January 4, 2012, 3:47pm UTC](https://forum.inductiveautomation.com/t/limitations-demo-version/3820/2 "2012-01-04T15:47:46Z")

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Here’s a few dumb questions: Is this problem in the designer? If so, what mode is the designer in?

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**Author:** ![JordanCClark](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jordancclark/32/83362_2.png) [@JordanCClark](https://forum.inductiveautomation.com/u/JordanCClark)\
**Post date:** [January 4, 2012, 4:07pm UTC](https://forum.inductiveautomation.com/t/limitations-demo-version/3820/3 "2012-01-04T16:07:11Z")

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I PM’d you on this from our conversation, but here’s the “public” version. 😉

In the designer: ![](https://us1.discourse-cdn.com/inductiveautomation/original/1X/46b76efa555c151a011621c6559fb68b1358c87f.png)

Also, if you go the Project properties dialog:

 ![](https://us1.discourse-cdn.com/inductiveautomation/original/1X/c05c5cae0ef9c72f304eb0346a1ee782d28a9b98.png)

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**Author:** ![merlijn](https://avatars.discourse-cdn.com/v4/letter/m/54ee81/32.png) [@merlijn](https://forum.inductiveautomation.com/u/merlijn)\
**Post date:** [January 7, 2012, 9:39am UTC](https://forum.inductiveautomation.com/t/limitations-demo-version/3820/4 "2012-01-07T09:39:35Z")

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Problem solved  
The problem was in the Designer  
I have changed the mode to read and write enable.

Thanks for your support