sfera-labs / exo-sense-py-modbus Goto Github PK

Hi, where can I found an example of the implementation of the Modbus slave?

For the function: def get_request(self, unit_addr_list, timeout=None)

Thanks

Hi,

Your library works perfectly! But I have a device that uses the "little endian byteorder".

How to add :

if lsb_first:
        formatcode = "<" # Little-endian
    else:
        formatcode = ">" # Big-endian

I think I'd have to add a constant for decoding

def read_holding_registers(starting_address: int, quantity: int) -> bytes:
    """
    Create Modbus Protocol Data Unit for reading holding registers.

    :param      starting_address:  The starting address
    :type       starting_address:  int
    :param      quantity:          Quantity of coils
    :type       quantity:          int

    :returns:   Packed Modbus message
    :rtype:     bytes
    """
    if not (1 <= quantity <= 125):
        raise ValueError('Invalid number of holding registers')

    return struct.pack('>BHH',
                       Const.READ_HOLDING_REGISTERS,
                       starting_address,
                       quantity)

I'd like to do it but I'm not sure of my abilities !

Thank you

Hello!
First, many thanks for tweaking original pycom lib, and share on github.

I'm using the library successfully with WiPy devices as Modbus TCP server, but there's some problem I can't find under another ESP32 board (olimex ESP32-POE) with micropython v1.11.
The exact same code works without problems under WiPy, but on micropython throws this error:

Traceback (most recent call last):
  File "main.py", line 47, in <module>
  File "modbus.py", line 44, in bind
  File "/lib/uModBus/tcp.py", line 144, in bind
TypeError: function takes 2 positional arguments but 1 were given

I've added a print over line 144:
self._sock.bind((socket.getaddrinfo(local_ip, local_port))[0][-1])
In order to see if local_ip and local_port have correct values and also checked socket.getaddrifo() returns the same tuple both with WiPy and Micropython.

At the moment I'm trying, but I'm not obtaining good results. Perhaps newer usocket library breaks something?

Best regards

Hi, I do some changes in the modbus.py, probably not implemented it correctly.
Can we communicate by email?
Where can I define Modbus slave address?