Hello everyone,
i’m an absolute newbie to home assistant and i hope my question is not too dump … 
What i want to do:
I have to solar inverters and i sum the solar production of these two inverters in my templates.yaml:
- sensor:
- name: Kaco PV Gesamt
unique_id: kaco_pv_gesamt
unit_of_measurement: kW
state: >
{{ ( states('sensor.kaco_watt_hours_1')|float + states('sensor.kaco_watt_hours_2')|float ) }}
This is working fine and i get my actual total solar power production, for example the value: 8,07 kW
Now i want to send these value to my heat pump via modbus.
I want to do this via an automation and via modbus TCP.
Here is what i’ve done in the automation.yaml:
- id: '1668426381693'
alias: IDM
description: ''
trigger:
- platform: time_pattern
seconds: "/30"
action:
- service: modbus.write_register
data:
address: 74
slave: 1
value: "{{ states('sensor.kaco_pv_gesamt') }}"
hub: idm
Sadly the value in the heat pump isn’t updating and i think it has something to do with wrong number formats or anything like that.
Address 74 in my heat pump:
Could anyone of you help me with my topic? 
Best regards and TIA for your help,
Chris