Dongubak
56 lines
1.9 KiB
Python
56 lines
1.9 KiB
Python
"""pymodbus-based helpers for the ZLAC8015D V4 RS485 (Modbus RTU) protocol.
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Register reference (from "ZLAC8015D V4 Series RS485 Communication" manual):
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0x2001 RS485 Custom Drive Node Number (RW/S, range 1-127, default 1)
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0x2002 RS485 custom communication baud rate (RW/S)
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0x2010 Save all RW attribute parameters to EEPROM (write 1 to save)
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Requires: pip install pymodbus pyserial
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"""
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from pymodbus.client import ModbusSerialClient
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REG_NODE_ID = 0x2001
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REG_SAVE_EEPROM = 0x2010
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# pymodbus renamed the "slave id" keyword across major versions
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# (unit -> slave -> device_id). Try each so this works regardless of
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# which pymodbus version is installed (e.g. on the Ubuntu test box).
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_ID_KWARGS = ("device_id", "slave", "unit")
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def _call(fn, *args, node_id, **kwargs):
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last_err = None
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for kw in _ID_KWARGS:
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try:
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return fn(*args, **{kw: node_id}, **kwargs)
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except TypeError as exc:
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last_err = exc
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continue
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raise TypeError(f"pymodbus client does not accept any of {_ID_KWARGS}: {last_err}")
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def make_client(port: str, baud: int = 115200, timeout: float = 0.3) -> ModbusSerialClient:
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return ModbusSerialClient(
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port,
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baudrate=baud,
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bytesize=8,
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parity="N",
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stopbits=1,
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timeout=timeout,
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)
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def read_register(client: ModbusSerialClient, node_id: int, address: int, count: int = 1):
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"""Return list of register values, or None on error/no response."""
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result = _call(client.read_holding_registers, address, node_id=node_id, count=count)
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if result is None or result.isError():
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return None
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return result.registers
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def write_register(client: ModbusSerialClient, node_id: int, address: int, value: int) -> bool:
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result = _call(client.write_register, address, value, node_id=node_id)
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if result is None or result.isError():
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return False
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return True
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