Technical Specifications:

• Model: SC4A-T-AD-1502-10-T1
• Series: SC4A
• Product Type: Safety Controller (SIS)
• Display: Color Touchscreen HMI (T)
• Input Configuration: Analog + Digital (AD) — 15 total inputs
• Output Configuration: 2 safety relay outputs (1502)
• Number of Safety Loops: 10 (10)
• SIL Rating: SIL 2 / SIL 3 (IEC 61511)
• Communication: Ethernet (100BASE-TX), PROFIBUS DP (optional)
• Power Supply: 24 V DC (redundant, dual supply capable)
• Protection Class: IP65 front panel (NEMA 4X)
• Redundancy: CPU and I/O redundancy available (hot standby)
• Diagnostics: Online diagnostics with 99%+ coverage
• Certifications: IEC 61508, IEC 61511, ATEX, FM, CSA

Functional Features:

• Configurable safety logic (AND, OR, NOT, timer, voting)
• Touchscreen-based configuration and monitoring
• Online modification of safety logic without shutdown (with proper procedure)
• Event logging with timestamp for forensic analysis
• Dual-channel voting for critical inputs (2oo3 architecture)
• Automatic diagnostics with fail-safe output on fault detection
• Compatible with Yokogawa CENTUM DCS for integrated safety and control

Performance Parameters:

• Safety Loop Response Time: ≤ 100 ms (typical)
• Diagnostic Coverage: ≥ 99%
• Proof Test Interval: Configurable (1 month to 12 months)
• MTBF (Mean Time Between Failures): ≥ 100 years (for dangerous undetected failures)
• Operating Temperature: -20 °C to +60 °C
• Humidity: 5–95% RH (non-condensing)

Material Composition:

• Housing: Die-cast aluminum alloy with conformal coating
• Front Panel: Glass touchscreen with protective overlay
• Terminal Blocks: Gold-plated contacts for high reliability
• Internal: Redundant CPU modules with gold-finger connectors

Structural Features:

• DIN rail or panel-mount installation
• Redundant power supply inputs (dual 24 V DC)
• Front-accessible terminal blocks with individual channel labeling
• Status LEDs for CPU, power, communication, and I/O status

Working Principle:
The SC4A continuously monitors safety-related process signals via its 15 inputs. The safety logic is executed by redundant CPUs in a 1oo2 (one-out-of-two) or 2oo3 (two-out-of-three) voting architecture. When a dangerous process condition is detected and the safety logic condition is satisfied, the controller drives the 2 safety relay outputs to their safe state (typically de-energizing to trip the final element). All operations are continuously self-monitored; any internal fault triggers a safe-state output.

Advantages & Highlights:

• SIL 2 / SIL 3 certified — meets the highest safety integrity requirements
• Touchscreen HMI simplifies configuration, testing, and troubleshooting
• 10 independent safety loops in a single compact controller
• Online logic modification capability reduces downtime during process changes
• Seamless integration with Yokogawa CENTUM VP/CS DCS systems

Applicable Industries:

• Oil and Gas (refineries, offshore platforms, LNG terminals)
• Chemical and Petrochemical Plants
• Power Generation (gas turbines, boilers)
• Pharmaceutical (reactor safety)
• Mining (gas detection, ventilation control)

Installation Requirements:

• Install in a dedicated safety cabinet separate from non-safety instrumentation
• Provide redundant 24 V DC power supplies from separate sources
• Use safety-rated (SIL-certified) cables and barriers for field wiring
• Ground the safety controller chassis to the plant earth grid (≤ 1 Ω)
• Maintain minimum 200 mm separation from high-voltage cables (> 400 V)
• Perform a Site Acceptance Test (SAT) and Factory Acceptance Test (FAT) before commissioning

Usage Precautions:

• Never bypass or defeat any safety function — this voids SIL certification
• Perform proof testing at the configured interval (mandatory for SIL compliance)
• Do not modify safety logic without following the formal Management of Change (MOC) procedure
• Keep firmware updated to the latest safety-certified version
• Log all configuration changes and maintenance activities for audit compliance