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HomeLynk as Modbus TCP/IP slave
#1
Hello!

Is it possible to setup a Homelynk as a Modbus slave on TCP/IP?

Regards!

P
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#2
Hi
Use this
http://openrb.com/lm-as-modbus-tcp-slave/
BR
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#3
Thanks!

/P
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#4
Hello!

This works fine in genneral but I have an issue with the temperature. When I set the datatype in the script to float16 I get wrong scale on the modbus side. For example if the temperature value is 7.5 on KNX side I get value 7 on modbus side. I should get 750. If I change the datatype in script to int16 it gets completely wrong because temperature on KNX are float16. Are there any way to integrate a multiplier in the script only for float16 objects?
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#5
You should make the conversion outside the script.  Use an virtual object for modbus and make simple event script  like this.

Code:
grp.update('virtual object address', event.getvalue()*100)
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#6
Hello!

Are there any limitations of the amount of adresses in this script above? Or are there any ather better way if there is a lot of adresses? I have a project where I have a modbus master that have to read about 300 adresses.

BR
Per-Åke
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#7
Hi,

Hard to say exactly as it depends on other processes in your controller like amount of KNX object updates etcetera. The indicator of limitations is most of the time the CPU load.

We tested a lot of scenarios / addressable limits and you can see them in this document: https://www.schneider-electric.com/en/download/document/AN017/

On page 13 you can see the results of a test with 1000 objects on a HW2 device (you can increase this on HW3).

So if your controller is not doing anything else then 300 objects should work just fine.

BR,

Erwin
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