tcp-modbus-aio

asyncio client library for tcp modbus devices. built on top of umodbus but extended for more industrial robustness and asyncio compat. the umodbus documentation is recommended reading to have any hope of using this code.

narrowly constructed for the use cases of Tutor Intelligence, but feel free to post an issue or PR if relevant to you.

usage

create a TCPModbusClient. once you have it, you can call the following methods on it:

• await conn.send_modbus_message(request_function, **kwargs): sends a umodbus.functions.ModbusFunction to the modbus device and returns the corresponding ModbusFunction reply.
• await conn.test_connection(): sends a modbus message to the device to ensure it's still operational (currently hardcoded to read coil 0) and return boolean of whether it succeeded. is implemented as a cached awaitable to allow you to spam this call.
• await conn.clear_tcp_connection(): kill the current TCP socket (a new one will automatically be created for the next request)
• await conn.log_watch(msg, memo_key="system_temperature", expiry_period_s=10, hz=1): spins up a background coroutine to log the result of that message for the next expiry_period seconds at hz frequency. memo_key is used to allow multiple calls to log_watch without having overlapping log watch loops.
• await conn.close(): for cleaning up the connection (kills TCP conn and ping loop)