1) DCS — Distributed Control Systems
Architecture & Features
- Redundant controllers, networks, and power (1+1, 2N)
- Remote/Marshalled I/O: HART-enabled, intrinsically safe options (Ex ia/ib)
- Industrial Ethernet: OPC UA, Modbus TCP, PROFINET, EtherNet/IP; historian connectors
- Batch & recipes: ISA-88 / IEC 61512; integrated historian & reporting
- Advanced control: PID libraries, MPC, soft sensors, embedded analytics
- Alarm management: ISA-18.2 / EEMUA 191 philosophy, KPIs, shelving & suppression
- Cybersecurity: IEC 62443 defense-in-depth, role-based access, secure remote access, patch mgmt
- Time sync: IEEE 1588 (IEC 61588) PTP for event fidelity
Standards & Good Practice
- IEC 61131-3 languages (LD/FBD/ST/SFC)
- ISA-95 / IEC 62264 (OT↔MES/ERP integration)
- IEC 62443 (IACS cybersecurity)
Deliverables
- Control narratives, cause & effect, alarm philosophy
- Network & I/O drawings, cable schedules
- FAT/SAT test scripts, maintenance & operator training
RFQ Checklist (DCS)
Process scope, I/O list (AI/AO/DI/DQ + HART), redundancy strategy, batch needs, integration points (MES/CMMS), cybersecurity level, FAT/SAT location & scope.
2) SIS — Safety Instrumented Systems
Positioning: Independent protection layers to reduce process risk to tolerable levels—designed, verified, and documented across the IEC 61511 safety lifecycle.
Core Concepts
- SIL 1–3 targets via LOPA; Safety Requirement Specification (SRS)
- Architectures: 1oo1, 1oo2, 2oo3 logic solvers & sensor/Final Element voting
- PFDavg calculation, proof-test intervals, diagnostic coverage, HFT per IEC 61508/61511
- Separation from BPCS/DCS; independent power and comms as required
- Final elements: partial-stroke testing (PST), solenoid monitoring, position feedback
- HIPPS, ESD, F&G integration with certified devices
Standards
- IEC 61511 (process SIS lifecycle) / IEC 61508 (functional safety of E/E/PE systems)
- SIL-capable devices and logic solvers with third-party certifications
Deliverables
- SRS, LOPA reports, verification/validation plan
- Proof-test procedures, bypass management, override logs
- Safety manual packs, as-built architecture & cause/effect
RFQ Checklist (SIS)
Target SIL per SIF, demand rates, trip setpoints, proof-test interval/coverage, voting logic, bypass rules, reporting & cybersecurity segregation.