3D SCADA FACILITY VIEW — PURDUE / ISA-95 MODEL
LEVEL 4 — ERP / BUSINESS
ERP System
Corporate Network
🔒 IT/OT Firewall (DMZ)
IEC 62443 zone conduit
LEVEL 3 — MES / HISTORIAN
Data Historian
MES Server
LEVEL 2 — SCADA / HMI
HMI Workstation
SCADA Server
🔒 OT/DMZ Firewall
NERC CIP-005 perimeter
LEVEL 1 — PLCs / REMOTE I/O
PLC Rack
Remote I/O Module
LEVEL 0 — FIELD DEVICES
Temp Sensor
Pressure TX
Flow Meter
Control Valve
VFD Motor
SCADA ARCHITECTURE — PURDUE / ISA-95 REFERENCE MODEL
L4 — Enterprise / Business
ERP SERVER
BUSINESS WS
⇡ TCP/IP via firewall + data diode (OT→IT one-way)
L3.5 — IDMZ / Security
FIREWALL
IDMZ ZONE
DATA DIODE
JUMP SERVER
⇡ OPC UA / SQL · historian replication
L3 — Operations / Data
HISTORIAN
OPC SERVER
APP / MES
⇡⇣ OPC UA / DNP3 · SCADA poll + control
L2 — Supervisory / Control Room
HMI / OP WS
SCADA PRIMARY
SCADA STANDBY
⇡⇣ Modbus TCP / EtherNet/IP / PROFINET
L1 — Basic Control (Controllers)
PLC
SAFETY PLC
RTU
REMOTE I/O
⇡⇣ 4-20mA / HART / PROFIBUS PA / Foundation Fieldbus
L0 — Field / Process
TEMP RTD/TC
PRESSURE TX
FLOW METER
CONTROL VALVE
VFD MOTOR
SCADA NETWORK TOPOLOGY — ZONES & CONDUITS (IEC 62443)
ENTERPRISE ZONE — Corporate IT LAN (Level 4)
ERP SERVER
BUSINESS WS
⇡ TCP/IP via firewall + data diode (unidirectional OT→IT)
INDUSTRIAL DMZ (IDMZ) — No direct OT↔IT path
FIREWALL ▲
IDMZ SERVERS
DATA DIODE →
JUMP SERVER
⇡ OPC UA replication · HTTPS broker · zone & conduit rules
CONTROL-CENTER LAN — Redundant Ring (L2/L3)
RING SWITCH A
ROUTER
GPS/NTP
⟲ MRP/RSTP ring
SCADA-1
SCADA-2
HISTORIAN
OPC SVR
HMI / OP WS
⇡ fiber (Modbus TCP / PROFINET / IEC 61850) · dedicated OT network
OT NETWORK — Field Control (Level 1/0)
PLC
SAFETY PLC
IED
REMOTE I/O
Field Sensors
⇠ DNP3 / IEC 60870-5-104 over licensed radio or LTE VPN
REMOTE SITE — RTU over Telemetry
RTU
TELEMETRY RADIO
LTE GATEWAY