309 lines
10 KiB
Python
309 lines
10 KiB
Python
"""Modbus client async serial communication."""
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from __future__ import annotations
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import contextlib
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import sys
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import time
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from collections.abc import Callable
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from functools import partial
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from pymodbus.client.base import ModbusBaseClient, ModbusBaseSyncClient
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from pymodbus.exceptions import ConnectionException
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from pymodbus.framer import FramerType
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from pymodbus.logging import Log
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from pymodbus.transport import CommParams, CommType
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from pymodbus.utilities import ModbusTransactionState
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with contextlib.suppress(ImportError):
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import serial
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class AsyncModbusSerialClient(ModbusBaseClient):
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"""**AsyncModbusSerialClient**.
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Fixed parameters:
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:param port: Serial port used for communication.
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Optional parameters:
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:param framer: Framer name, default FramerType.RTU
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:param baudrate: Bits per second.
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:param bytesize: Number of bits per byte 7-8.
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:param parity: 'E'ven, 'O'dd or 'N'one
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:param stopbits: Number of stop bits 1, 1.5, 2.
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:param handle_local_echo: Discard local echo from dongle.
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:param name: Set communication name, used in logging
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:param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
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:param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
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:param timeout: Timeout for a connection request, in seconds.
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:param retries: Max number of retries per request.
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:param on_reconnect_callback: Function that will be called just before a reconnection attempt.
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.. tip::
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**reconnect_delay** doubles automatically with each unsuccessful connect, from
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**reconnect_delay** to **reconnect_delay_max**.
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Set `reconnect_delay=0` to avoid automatic reconnection.
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Example::
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from pymodbus.client import AsyncModbusSerialClient
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async def run():
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client = AsyncModbusSerialClient("dev/serial0")
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await client.connect()
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...
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client.close()
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Please refer to :ref:`Pymodbus internals` for advanced usage.
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"""
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def __init__( # pylint: disable=too-many-arguments
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self,
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port: str,
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framer: FramerType = FramerType.RTU,
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baudrate: int = 19200,
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bytesize: int = 8,
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parity: str = "N",
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stopbits: int = 1,
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handle_local_echo: bool = False,
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name: str = "comm",
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reconnect_delay: float = 0.1,
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reconnect_delay_max: float = 300,
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timeout: float = 3,
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retries: int = 3,
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on_connect_callback: Callable[[bool], None] | None = None,
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) -> None:
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"""Initialize Asyncio Modbus Serial Client."""
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if "serial" not in sys.modules:
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raise RuntimeError(
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"Serial client requires pyserial "
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'Please install with "pip install pyserial" and try again.'
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)
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self.comm_params = CommParams(
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comm_type=CommType.SERIAL,
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host=port,
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baudrate=baudrate,
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bytesize=bytesize,
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parity=parity,
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stopbits=stopbits,
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handle_local_echo=handle_local_echo,
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comm_name=name,
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reconnect_delay=reconnect_delay,
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reconnect_delay_max=reconnect_delay_max,
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timeout_connect=timeout,
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)
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ModbusBaseClient.__init__(
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self,
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framer,
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retries,
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on_connect_callback,
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)
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def close(self, reconnect: bool = False) -> None:
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"""Close connection."""
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super().close(reconnect=reconnect)
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class ModbusSerialClient(ModbusBaseSyncClient):
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"""**ModbusSerialClient**.
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Fixed parameters:
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:param port: Serial port used for communication.
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Optional parameters:
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:param framer: Framer name, default FramerType.RTU
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:param baudrate: Bits per second.
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:param bytesize: Number of bits per byte 7-8.
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:param parity: 'E'ven, 'O'dd or 'N'one
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:param stopbits: Number of stop bits 0-2.
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:param handle_local_echo: Discard local echo from dongle.
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:param name: Set communication name, used in logging
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:param reconnect_delay: Minimum delay in seconds.milliseconds before reconnecting.
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:param reconnect_delay_max: Maximum delay in seconds.milliseconds before reconnecting.
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:param timeout: Timeout for a connection request, in seconds.
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:param retries: Max number of retries per request.
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.. tip::
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**reconnect_delay** doubles automatically with each unsuccessful connect, from
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**reconnect_delay** to **reconnect_delay_max**.
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Set `reconnect_delay=0` to avoid automatic reconnection.
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Example::
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from pymodbus.client import ModbusSerialClient
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def run():
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client = ModbusSerialClient("dev/serial0")
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client.connect()
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...
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client.close()
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Please refer to :ref:`Pymodbus internals` for advanced usage.
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Remark: There are no automatic reconnect as with AsyncModbusSerialClient
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"""
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state = ModbusTransactionState.IDLE
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inter_byte_timeout: float = 0
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silent_interval: float = 0
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def __init__( # pylint: disable=too-many-arguments
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self,
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port: str,
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framer: FramerType = FramerType.RTU,
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baudrate: int = 19200,
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bytesize: int = 8,
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parity: str = "N",
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stopbits: int = 1,
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handle_local_echo: bool = False,
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name: str = "comm",
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reconnect_delay: float = 0.1,
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reconnect_delay_max: float = 300,
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timeout: float = 3,
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retries: int = 3,
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) -> None:
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"""Initialize Modbus Serial Client."""
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self.comm_params = CommParams(
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comm_type=CommType.SERIAL,
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host=port,
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baudrate=baudrate,
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bytesize=bytesize,
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parity=parity,
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stopbits=stopbits,
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handle_local_echo=handle_local_echo,
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comm_name=name,
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reconnect_delay=reconnect_delay,
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reconnect_delay_max=reconnect_delay_max,
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timeout_connect=timeout,
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)
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super().__init__(
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framer,
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retries,
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)
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if "serial" not in sys.modules:
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raise RuntimeError(
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"Serial client requires pyserial "
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'Please install with "pip install pyserial" and try again.'
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)
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self.socket: serial.Serial | None = None
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self.last_frame_end = None
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self._t0 = float(1 + bytesize + stopbits) / baudrate
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# Check every 4 bytes / 2 registers if the reading is ready
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self._recv_interval = self._t0 * 4
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# Set a minimum of 1ms for high baudrates
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self._recv_interval = max(self._recv_interval, 0.001)
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if baudrate > 19200:
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self.silent_interval = 1.75 / 1000 # ms
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else:
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self.inter_byte_timeout = 1.5 * self._t0
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self.silent_interval = 3.5 * self._t0
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self.silent_interval = round(self.silent_interval, 6)
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@property
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def connected(self):
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"""Connect internal."""
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return self.connect()
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def connect(self) -> bool:
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"""Connect to the modbus serial server."""
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if self.socket:
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return True
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try:
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self.socket = serial.serial_for_url(
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self.comm_params.host,
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timeout=self.comm_params.timeout_connect,
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bytesize=self.comm_params.bytesize,
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stopbits=self.comm_params.stopbits,
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baudrate=self.comm_params.baudrate,
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parity=self.comm_params.parity,
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exclusive=True,
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)
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self.socket.inter_byte_timeout = self.inter_byte_timeout
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self.last_frame_end = None
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# except serial.SerialException as msg:
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# pyserial raises undocumented exceptions like termios
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except Exception as msg: # pylint: disable=broad-exception-caught
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Log.error("{}", msg)
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self.close()
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return self.socket is not None
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def close(self):
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"""Close the underlying socket connection."""
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if self.socket:
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self.socket.close()
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self.socket = None
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def _in_waiting(self):
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"""Return waiting bytes."""
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return getattr(self.socket, "in_waiting") if hasattr(self.socket, "in_waiting") else getattr(self.socket, "inWaiting")()
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def send(self, request: bytes) -> int:
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"""Send data on the underlying socket.
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If receive buffer still holds some data then flush it.
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Sleep if last send finished less than 3.5 character times ago.
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"""
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super()._start_send()
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if not self.socket:
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raise ConnectionException(str(self))
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if request:
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if waitingbytes := self._in_waiting():
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result = self.socket.read(waitingbytes)
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Log.warning("Cleanup recv buffer before send: {}", result, ":hex")
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if (size := self.socket.write(request)) is None:
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size = 0
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return size
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return 0
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def _wait_for_data(self) -> int:
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"""Wait for data."""
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size = 0
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more_data = False
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condition = partial(
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lambda start, timeout: (time.time() - start) <= timeout,
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timeout=self.comm_params.timeout_connect,
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)
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start = time.time()
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while condition(start):
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available = self._in_waiting()
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if (more_data and not available) or (more_data and available == size):
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break
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if available and available != size:
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more_data = True
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size = available
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time.sleep(self._recv_interval)
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return size
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def recv(self, size: int | None) -> bytes:
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"""Read data from the underlying descriptor."""
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if not self.socket:
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raise ConnectionException(str(self))
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if size is None:
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size = self._wait_for_data()
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if size > self._in_waiting():
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self._wait_for_data()
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result = self.socket.read(size)
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return result
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def is_socket_open(self) -> bool:
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"""Check if socket is open."""
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if self.socket:
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return self.socket.is_open
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return False
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def __repr__(self):
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"""Return string representation."""
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return (
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f"<{self.__class__.__name__} at {hex(id(self))} socket={self.socket}, "
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f"framer={self.framer}, timeout={self.comm_params.timeout_connect}>"
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)
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