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🛡️ Integration of SIS with DCS — Explained Simply

In modern plants, SIS and DCS work together… but they must remain independent 👇

⚙️ What is DCS?

➡️ Distributed Control System
➡️ Handles normal process control

Controls:
🔹 Temperature
🔹 Pressure
🔹 Flow
🔹 Level

👉 Goal = Keep process running

⚙️ What is SIS?

➡️ Safety Instrumented System
➡️ Protects plant during dangerous conditions

👉 Goal = Keep process safe

🔗 Why integrate SIS with DCS?

❌ DCS should NOT control SIS safety logic
✅ SIS must remain independent

🏭 Typical integration data

📡 Trip status
📡 Bypass status
📡 SOE (Sequence of Events)
📡 Fault diagnostics
📡 Shutdown indications

🚨 Real example

🔥 High pressure detected

👉 DCS tries normal control
👉 If pressure continues rising → SIS trips process
👉 DCS displays trip/alarm to operator

🎯 Key takeaway

🟢 DCS = Process control
🔴 SIS = Process protection