OPC-UA Bridge

Connect the Methanol APC Environment to real plant DCS/SCADA systems via OPC Unified Architecture — the standard industrial communication protocol used by Honeywell Experion, ABB 800xA, Siemens PCS 7, Yokogawa CENTUM, and Emerson DeltaV.

Setup

pip install asyncua

No other configuration needed for server mode. For client mode, set:

export OPCUA_ENDPOINT=opc.tcp://plant-dcs.local:4840

Two Operating Modes

Server Mode — Shadow Deployment

Exposes the simulation as an OPC-UA server. Real HMI/SCADA systems connect to read simulated sensor values. Use this to:

Display AI suggestions alongside human operator actions
Validate agent behavior before switching to live control
Train operators on the AI's decision-making patterns

from methanol_apc_env.integrations import OPCUABridge

bridge = OPCUABridge(mode="server", endpoint="opc.tcp://0.0.0.0:4840")
await bridge.start()

# After each simulation step, publish state
await bridge.publish_state(reactor_state)

# Read setpoints written by external HMI operator
operator_setpoints = await bridge.read_setpoints()

await bridge.stop()

Client Mode — Live Plant Connection

Connects to a real plant's OPC-UA server. Reads live sensor data and writes agent actions to real actuators.

Safety

Client mode writes to real actuators. Only use after thorough validation in simulation mode and shadow mode.

bridge = OPCUABridge(mode="client", endpoint="opc.tcp://plant-dcs.local:4840")
await bridge.connect()

# Read live sensor data
readings = await bridge.read_plant_tags()
# {"temperature": 252.3, "pressure": 81.2, "catalyst_health": 0.93, ...}

# Write agent actions to DCS
await bridge.write_action({
    "feed_rate_h2": 5.2,
    "cooling_water_flow": 42.0,
    "compressor_power": 67.0,
})

await bridge.disconnect()

OPC-UA Tag Mapping

Tags follow the ISA-95 naming convention: Area.Unit.Instrument.Measurement

Process Values (PV) — Agent Reads These

OPC-UA Tag	ReactorState Field	Unit	Description
`METHANOL.REACTOR.TI001.PV`	`temperature`	°C	Reactor bulk temperature
`METHANOL.REACTOR.PI001.PV`	`pressure`	bar	Reactor pressure
`METHANOL.REACTOR.FI001.PV`	`feed_rate_h2`	mol/s	Hydrogen feed rate
`METHANOL.REACTOR.FI002.PV`	`feed_rate_co`	mol/s	CO feed rate
`METHANOL.REACTOR.FI003.PV`	`cooling_water_flow`	L/min	Cooling water flow
`METHANOL.REACTOR.TI002.PV`	`cooling_water_temp`	°C	Cooling water inlet temp
`METHANOL.REACTOR.AI001.PV`	`catalyst_health`	0–1	Catalyst activity
`METHANOL.REACTOR.FI004.PV`	`reaction_rate`	mol/s	Methanol formation rate
`METHANOL.REACTOR.XI001.PV`	`compressor_power`	kW	Compressor power
`METHANOL.REACTOR.FI005.PV`	`methanol_produced`	kg	Cumulative methanol
`METHANOL.REACTOR.CI001.PV`	`cumulative_profit`	$	Total profit
`METHANOL.REACTOR.RI001.PV`	`h2_co_ratio`	—	H₂/CO molar ratio
`METHANOL.REACTOR.ZI001.PV`	`emergency_shutdown`	bool	Shutdown flag

Setpoints (SP) — Agent Writes These

OPC-UA Tag	Action Field	Unit
`METHANOL.REACTOR.FI001.SP`	`feed_rate_h2`	mol/s
`METHANOL.REACTOR.FI002.SP`	`feed_rate_co`	mol/s
`METHANOL.REACTOR.FI003.SP`	`cooling_water_flow`	L/min
`METHANOL.REACTOR.XI001.SP`	`compressor_power`	kW
`METHANOL.REACTOR.FV001.SP`	`purge_valve_position`	%
`METHANOL.REACTOR.FI006.SP`	`recycle_ratio`	—
`METHANOL.REACTOR.TI003.SP`	`feed_preheat_temp`	°C
`METHANOL.REFORMER.FI001.SP`	`reformer_fuel_gas`	mol/s
`METHANOL.REFORMER.FI002.SP`	`reformer_steam_flow`	mol/s
`METHANOL.DISTILL.RI001.SP`	`distillation_reflux`	—
`METHANOL.DISTILL.QI001.SP`	`reboiler_duty`	kW
`METHANOL.REACTOR.FV002.SP`	`flare_valve`	%

Security

For production plant networks, enable OPC-UA security:

from methanol_apc_env.integrations.opcua_bridge import OPCUAConfig

config = OPCUAConfig(
    endpoint="opc.tcp://plant-dcs.local:4840",
    security_policy="Basic256Sha256",
    certificate_path="/path/to/client_cert.pem",
    private_key_path="/path/to/client_key.pem",
)
bridge = OPCUABridge(mode="client", config=config)

Deployment Path

Simulation → Train agent on reactor_sim.py (no OPC-UA needed)
Shadow mode → OPC-UA server exposes sim alongside real HMI
Pilot → OPC-UA client reads real sensors, suggests actions (human approves)
Production → OPC-UA client writes setpoints directly to DCS