Help with a first knx to modbus

[stevesu]

Hi everyone,
i have a project coming up where i have to control a Danfoss novoCom 6 valve trough the modbus interface on a spacelynk, after  reading several documents en guides i managed to write the json profile wich i uploaded to the spacelynk (the profile ,if working , i am happy to post it on the forum).

Now the next qeustion i have, if i go throug the manual provided by Schneider i have to make scripts to control the valve or have i misunderstood it, or do i have to link the grp.adres with the percentual value from thermostat to the profile ?

If someone can help me with this i would greatly appreciate it

with regards steven

[Daniel]

Hi
If you add "writable": 1 then any value written to the mapped address will be sent to modbus.
BR

[stevesu]

hi Daniel,
first i want to thank you for the reply but it was really busy the last two weeks with the project.

i managed to write a profile and it works for a part , switching between cooling and heating works but when i want to send a % value to the valve
i get no response from the valve (feedback trough a register or visual by LED's on the valve), first i got errors but then i changed type from "register" to "input register" and the errors are gone but like i said no respons on the valve .

if someone can look into it , i attach the profile and the a piece of the datasheet of the valve into the reply.

i really hope someone can give me a hand with it


greatings steven

[Daniel]

Hi
Input register can be only read.  To read and write you have to use holding register.
Try RTU Read test to find correct settings.
BR

[stevesu]

so if i understand well when i set "writeable : true" the type is "register" and if it is "false"   then it is "input_register" ?

[Daniel]

https://en.wikipedia.org/wiki/Modbus

[stevesu]

so if i use following for writing to register 33280 , witch have functioncode 3,4 & 16 (datasheet)

Code:

{ "name": "Flow Rate Setpoint", "bus_datatype": "05", "type": "register", "address":33280, "writable": true , "value_delta": "0", "datatype": "float16" },

and for only reading the actual setpoint in register 33282 , witch have functioncode 3,4

Code:

{ "name": "Actual Flow Rate", "bus_datatype": "05", "type": "inputregister", "address":33282, "writable": 0, "value_delta": "0" , "datatype": "float16" },

ps: when i read "register" i must actually read "holding register".

sorry for asking these qeustions, but it is all new for me and having someone to explane it  makes it a bit easier

[Daniel]

You can use register for reead and write.
Use RTU read test to find correct settings. Most likely modbus dpt is nof float only int16