I have a question about how to handle register address.

[gunji-m]

Hello everyone.

I have a question about how to handle address.
The value next to the address specified by the client (30000 in this case) will be returned.
The address of validata-log? on the server side is already 30000, but
How can I get the value of the target address?

Is there a way to do this by incrementing the address by 1 when mapping the register and then storing it in the data block?

-------- Logs ----------

• • Client log - - - - -
    DEBUG:pymodbus.logging:Connection to Modbus server established. Socket ('192.168.11.24', any port number)
    Modbus Client Connected!!
    INFO:main:Modbus Client Connected.
    unit_number :1
    regist (ir or hr) : ir
    address :30000
    count : 1
    DEBUG:pymodbus.logging:Processing: 0x0 0x1 0x0 0x0 0x0 0x5 0x1 0x4 0x2 0x4e 0x32
    DEBUG:pymodbus.logging:decoded PDU function_code(4 sub -1) -> ReadInputRegistersResponse(dev_id=0, transaction_id=0, address=0, count=0, bits=[], registers=[20018], status=1)
    DEBUG:pymodbus.logging:Frame advanced, resetting header!!

(print result) [address 30001's value]

Modbus Client Closed

---

• • Server log - - - - -
    DEBUG:pymodbus.logging:Awaiting connections server_listener
    INFO:pymodbus.logging:Server listening.
    DEBUG:pymodbus.logging:Connected to server
    DEBUG:pymodbus.logging:recv: 0x0 0x1 0x0 0x0 0x0 0x6 0x1 0x4 0x75 0x30 0x0 0x1 old_data: addr=None
    DEBUG:pymodbus.logging:Processing: 0x0 0x1 0x0 0x0 0x0 0x6 0x1 0x4 0x75 0x30 0x0 0x1
    DEBUG:pymodbus.logging:decoded PDU function_code(4 sub -1) -> ReadInputRegistersRequest(dev_id=0, transaction_id=0, address=30000, count=1, bits=[], registers=[], status=1)
    DEBUG:pymodbus.logging:Frame advanced, resetting header!!
    DEBUG:pymodbus.logging:validate: fc-[4] address-30001: count-1
    DEBUG:pymodbus.logging:getValues: fc-[4] address-30001: count-1
    DEBUG:pymodbus.logging:send: 0x0 0x1 0x0 0x0 0x0 0x5 0x1 0x4 0x2 0x4e 0x32
    DEBUG:pymodbus.logging:-> transport: received eof
    DEBUG:pymodbus.logging:Connection lost server due to None
    DEBUG:pymodbus.logging:Handler for stream [server] has been canceled

---

[gunji-m]

I don't have enough experience, and there are many things I don't understand.
I have a question about how to handle the register addresses in the following part.

https://github.com/pymodbus-dev/pymodbus/blob/dev/pymodbus/datastore/context.py

pymodbus > datastore > context.py
Lines 119, 131, and 142 here

address += 1

What is the intention of this?

I deliberately commented out this part and tried the Server, and it seemed to resolve the address discrepancy.

However, I expect this will only apply to my environment, so I don't think it's the right thing to do.
If I'm wrong I'd like some advice.

thank you.

[janiversen]

The intention is that older modbus devices did that address 1 in the server was to be requested as address 0 in the communication.

The newer data stores in pymodbus uses the communication address meaning 0==0.

But what is the real problem....you CONFIGURE the server in one way and REQUEST the data in another way ? just wait until you start with coils that are adressed differently or non-shared register spaces.

Anyhow if you want changes then pull requests are welcome.

[gunji-m]

Veo…
De modo que hay un trasfondo para la diferente forma de pensar en las direcciones. Gracias.

Cómo configurar el servidor:
Siguiendo el ejemplo compartido en la documentación, lo configuramos utilizando el Contexto y Datastore proporcionado por pymodbus.
Pretendo adaptarlo a los formatos de argumentos requeridos por cada clase y otras funciones.

Al solicitar datos, en client.py, por ejemplo, los datos se obtienen de HoldingRegister utilizando read_holding_registers().
(Usando clases y funciones proporcionadas por pymodbus)

No creo que estén solicitando ninguna configuración de servidor o datos particularmente extraños. . . tal vez. . .

Gracias por tu respuesta.
No es imprescindible realizar el cambio con urgencia, por lo que intentaré gestionarlo yo mismo de forma que se ajuste a estas especificaciones.

(Traducción: Japonés → Español)

[janiversen]

This es an english forum.

please look at our examples and documentation where it is shown how to configure a server.