# Power Meter - KNX - node red - Modbus - PV Inverter

**URL:** <https://discourse.nodered.org/t/power-meter-knx-node-red-modbus-pv-inverter/82283>\
**Category:** General\
**Tags:** modbus\
**Created:** [23 October 2023 13:47 UTC](https://discourse.nodered.org/t/power-meter-knx-node-red-modbus-pv-inverter/82283 "2023-10-23T13:47:53Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![colalight890](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@colalight890](https://discourse.nodered.org/u/colalight890)\
**Post date:** [23 October 2023 13:47 UTC](https://discourse.nodered.org/t/power-meter-knx-node-red-modbus-pv-inverter/82283/1 "2023-10-23T13:47:53Z")

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Halllo all,

I am new to the forum and also completely inexperienced with Node red. But I hope to learn quickly.

My goal is to provide the electric power values to the inverter - the inverter is the Modbus master - Node Red should be the slave:

Data from KNX Power Meter =\> KNX Node Red =\> Node Red Modbus Client with USB adapter (PI) \<= Hybrid Inverter

Does anyone happen to have such a solution, or can go with tips.

Many many thanks already  
Franz

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**Author:** ![marcus-j-davies](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/marcus-j-davies/32/103435_2.png) [@marcus-j-davies](https://discourse.nodered.org/u/marcus-j-davies)\
**Post date:** [23 October 2023 13:55 UTC](https://discourse.nodered.org/t/power-meter-knx-node-red-modbus-pv-inverter/82283/2 "2023-10-23T13:55:56Z")

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Welcome @colalight890

Just to let you know - I have moved your question away from **Core Development** - as its not about the core/internals of Node RED.

I don't use any modbus / KNX stuff, but plenty here who do.

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [23 October 2023 14:37 UTC](https://discourse.nodered.org/t/power-meter-knx-node-red-modbus-pv-inverter/82283/3 "2023-10-23T14:37:49Z")

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> [@colalight890](#):
>
> the inverter is the Modbus master - Node Red should be the slave:

Are you sure? Normally that would be the other way round, with node red accessing registers on the device.

If you do want node-red to be a modbus server, however, node-red-contrib-modbus has a server node, though I have never used it.

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**Author:** ![colalight890](https://avatars.discourse-cdn.com/v4/letter/c/ccd318/32.png) [@colalight890](https://discourse.nodered.org/u/colalight890)\
**Post date:** [23 October 2023 14:53 UTC](https://discourse.nodered.org/t/power-meter-knx-node-red-modbus-pv-inverter/82283/4 "2023-10-23T14:53:05Z")

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Hello Colin,  
The Inverter is the master and asking the Power Meter in this case. So Node Red must play the Slave role 🙂  
For Node Red, Server = Slave - right?

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**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [23 October 2023 14:54 UTC](https://discourse.nodered.org/t/power-meter-knx-node-red-modbus-pv-inverter/82283/5 "2023-10-23T14:54:41Z")

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> [@colalight890](#):
>
> Server = Slave - right?

Yes. Let us know whether the server node does what you need.

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [22 December 2023 14:54 UTC](https://discourse.nodered.org/t/power-meter-knx-node-red-modbus-pv-inverter/82283/6 "2023-12-22T14:54:58Z")

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