drivers.PyModbus.PyModbus¶

Modbus client wrapper for Oizom IoT sensor drivers.

Centralizes Modbus communications for all driver consumers in the Oizom firmware by wrapping the pymodbus library. Exposes a Modbus server (TCP or RTU over RS-485) that holds a configurable bank of 32-bit IEEE-754 float registers which the firmware updates on every sensing cycle so that external SCADA, PLC, and gateway clients can poll the latest sensor values.

This module is a utility (not a sensor driver) and is shared by all Modbus-based sensor drivers in drivers that need to publish data to upstream Modbus masters.

Example

>>> from drivers.PyModbus.PyModbus import PyModbus
>>> server = PyModbus(size=20)
>>> ctx = server.build_context(slaveId=1, fixId=True)
>>> server.update_data(1, 3, 0, 23.5)
>>> server.run_tcp_server("0.0.0.0", 5020)

Note

Two transports are supported and chosen at runtime by the consumer:

Modbus TCP - networked transport over Ethernet/Wi-Fi, started with PyModbus.run_tcp_server().
Modbus RTU - serial transport over RS-485, started with PyModbus.run_rtu_server().

Four common Modbus register types are pre-allocated by PyModbus.build_context():

di - Discrete Inputs (read-only bits, function code 0x02).
co - Coils (read/write bits, function codes 0x01 / 0x05 / 0x0F).
hr - Holding Registers (read/write 16-bit words, codes 0x03 / 0x06 / 0x10). Used to publish 32-bit floats as register pairs.
ir - Input Registers (read-only 16-bit words, code 0x04).

See pymodbus for the underlying protocol implementation and consumer drivers under drivers for usage patterns.

Attributes¶

`basic_logger`
`context_logger`
`pymodbus`

Classes¶

PyModbus

Modbus server wrapper for exposing sensor data over TCP or RTU.

Module Contents¶

drivers.PyModbus.PyModbus.basic_logger¶

drivers.PyModbus.PyModbus.context_logger¶

drivers.PyModbus.PyModbus.pymodbus¶