midas

Python driver for Honeywell Midas gas detectors.

Installation

uv pip install midas

Usage

Command Line

To test your connection and stream real-time data, use the command-line interface. You can read the state with:

$ midas 192.168.1.100

This will output a JSON object which can be further manipulated. See below for object structure.

Python

For more complex behavior, you can write a python script. This solely uses Python ≥3.5's async/await syntax.

import asyncio
from midas import GasDetector

async def get():
    async with GasDetector('192.168.1.100') as detector:
        print(await detector.get())

asyncio.run(get())

If the detector is operating at that address, this should output a dictionary of the form:

{
  'alarm': 'none',             # Can be 'none', 'low', or 'high'
  'concentration': 0.0,        # Current gas concentration reading
  'connected': True,           # Monitors heartbeat for connection
  'fault': {                   # Fault data, when applicable
    'code': 'F39',
    'condition': 'User has generated a simulated fault.',
    'description': 'Simulated fault',
    'recovery': 'Reset simulated fault.',
    'status': 'Instrument fault'
  },
  'flow': 514,                 # Flow rate, in cc / minute
  'high-alarm threshold': 2.0, # Threshold concentration for high alarm trigger
  'ip': '192.168.1.192',       # IP address of connection, can be used to link to Honeywell's own web interface
  'life': 538.95,              # Days until cartridge replacement required
  'low-alarm threshold': 1.0,  # Threshold concentration for low alarm trigger
  'state': 'Monitoring',       # Can be any option in `gas_detector.monitoring_status_options`
  'temperature': 26,           # Detector temperature, in celsius
  'units': 'ppm'               # Units for concentration values
}

Additionally, there are four commands which can be sent to the device

• Clear all alarms and faults - detector.clear_alarms_and_faults()
• Inhibit alarms - detector.inhibit_alarms()
• Inhibit alarms and faults - detector.inhibit_alarms_and_faults()
• Turn off inhibition - detector.remove_inhibit()