# BAOS 777 KNX interface - Web service data to Tags

**URL:** <https://forum.inductiveautomation.com/t/baos-777-knx-interface-web-service-data-to-tags/44186>\
**Category:** Maker\
**Tags:** scripting\
**Created:** [March 6, 2021, 6:55pm UTC](https://forum.inductiveautomation.com/t/baos-777-knx-interface-web-service-data-to-tags/44186 "2021-03-06T18:55:30Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Happ](https://avatars.discourse-cdn.com/v4/letter/h/e9c0ed/32.png) [@Happ](https://forum.inductiveautomation.com/u/Happ)\
**Post date:** [March 6, 2021, 6:55pm UTC](https://forum.inductiveautomation.com/t/baos-777-knx-interface-web-service-data-to-tags/44186/1 "2021-03-06T18:55:30Z")

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Hi,  
Im quite newbie with Ignition but I want to use Maker for my home automation system UI. My system has this BAOS 777 KNX-eth gateway. It has web service where you can Get or Set values from/to KNX bus.  
Example: [http://xxx.xxx.xxx.xxx//baos/GetDatapointValue?DatapointStart=55&DatapointCount=1&Format=](http://xxx.xxx.xxx.xxx//baos/GetDatapointValue?DatapointStart=55&DatapointCount=1&Format=) Default  
This gives me answer: {“Data”:[{“Datapoint”:55,“Format”:“DPT9”,“Length”:2,“State”:16,“Value”:21.1}],“Result”:true,“Service”:“GetDatapointValue”}  
or you can ask multiple values same time by setting DatapointCount=“wantedcount”. Then I get response: {“Data”:[{“Datapoint”:49,“Format”:“DPT1”,“Length”:1,“State”:0,“Value”:false},{“Datapoint”:50,“Format”:“DPT3”,“Length”:1,“State”:0,“Value”:{“Control”:false,“StepCode”:0}},{“Datapoint”:51,“Format”:“DPT5”,“Length”:1,“State”:0,“Value”:0},{“Datapoint”:52,“Format”:“DPT1”,“Length”:1,“State”:0,“Value”:false},{“Datapoint”:53,“Format”:“DPT3”,“Length”:1,“State”:0,“Value”:{“Control”:false,“StepCode”:0}},{“Datapoint”:54,“Format”:“DPT1”,“Length”:1,“State”:0,“Value”:false},{“Datapoint”:55,“Format”:“DPT9”,“Length”:2,“State”:16,“Value”:21.6}],“Result”:true,“Service”:“GetDatapointValue”}

Then to my question: What is best way to get values to tags? I tried to read value to tag by using UDT where expression tag reads value from httpget and use value in derived tag {source} value but jsonGet it didnt work. Is it best way to read all values in script (1000ms interval) and write to tags? How I can parse “value” from that json?

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<div class="post-metadata">

**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [March 6, 2021, 7:09pm UTC](https://forum.inductiveautomation.com/t/baos-777-knx-interface-web-service-data-to-tags/44186/2 "2021-03-06T19:09:28Z")

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What doesn’t work about jsonGet?

I put the sample JSON data into a String tag and extracted the value using another expression tag with this expression:

```auto
jsonGet({[~]JsonData}, "Data[0].Value")

```

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<div class="post-metadata">

**Author:** ![Happ](https://avatars.discourse-cdn.com/v4/letter/h/e9c0ed/32.png) [@Happ](https://forum.inductiveautomation.com/u/Happ)\
**Post date:** [March 6, 2021, 8:39pm UTC](https://forum.inductiveautomation.com/t/baos-777-knx-interface-web-service-data-to-tags/44186/3 "2021-03-06T20:39:51Z")

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Thanks, now I got it work. I added Data[0] to my expression.