Technical Specifications:

• Number of Channels: 4 channels
• Input Type: RTD (Pt100, Pt1000, Cu50, Cu100, JPt100)
• Redundancy Configuration: PRP (Redundant pair)
• Input Resistance Range: 0 to 400 Ω (Pt100), 0 to 4000 Ω (Pt1000)
• Measurement Method: 3-wire or 4-wire RTD
• A/D Resolution: 16-bit
• Conversion Time: 250 ms per channel (all channels)
• Accuracy: ±0.1% of span (at 25 °C ambient)
• Temperature Drift: ±15 ppm/°C
• Isolation: 500 V AC between channels, 500 V AC channel to backplane
• Power Consumption: 1.5 W per module (typical)
• Operating Temperature: 0 to 55 °C (32 to 131 °F)
• Humidity: 5 to 95% RH (non-condensing)
• Mounting: DIN rail or direct mounting in FA-M3 rack
• Dimensions: 25 × 90 × 130 mm (W × H × D) approximately

Functional Features:

• 3-Wire RTD Compensation: Built-in lead wire resistance compensation eliminates errors from long cable runs
• 4-Wire RTD Support: Full 4-wire configuration available for highest accuracy
• Cold Junction Compensation: Automatic compensation for thermocouple reference junction (when used in mixed configurations)
• Redundant Operation: PRP configuration enables seamless switchover on primary module failure
• Online Diagnostics: Channel status, wire break detection, and sensor fault indication
• Self-Diagnosis: Module-level self-test on power-up and during operation

Performance Parameters:

• Input Impedance: 1 MΩ (typical)
• Common Mode Rejection Ratio (CMRR): 120 dB minimum at 50/60 Hz
• Normal Mode Rejection Ratio (NMRR): 80 dB minimum at 50/60 Hz
• Backplane Communication: FA-M3 high-speed serial bus
• Update Rate: 4 scans per second (all 4 channels)
• Alarm Thresholds: Configurable high/low alarms per channel

Structural Features:

• FA-M3 standard module format
• Front-facing terminal blocks for field wiring
• LED indicators per channel (power, active, alarm)
• Redundant backplane connector for PRP configuration
• DIN rail clip or screw mounting option

Working Principle:
The SAI143 module receives RTD resistance signals from field sensors via 3-wire or 4-wire connections. An internal constant current source excites the RTD element, and the resulting voltage drop is measured by a precision A/D converter. The 16-bit digital value is transmitted to the FA-M3 central processor via the backplane bus. In PRP configuration, a second identical module runs in parallel, and the system automatically switches to the backup module upon detection of a primary module fault.

Advantage Highlights:

• Redundant Architecture: PRP configuration ensures zero-downtime operation in critical processes
• High Accuracy RTD Measurement: ±0.1% span accuracy with 3-wire lead compensation
• FA-M3 Integration: Seamless integration with Yokogawa FA-M3 DCS platform
• Online Replaceability: Hot-swappable module design for maintenance without process shutdown
• Comprehensive Diagnostics: Per-channel LED status and system-level fault reporting

Applicable Industries:

• Oil refineries
• Chemical plants
• Power plants (thermal, nuclear, combined cycle)
• Water treatment facilities
• Pharmaceutical production
• Steel and metal processing

Installation Requirements:

• Install in FA-M3 compatible rack or DIN rail enclosure
• Ensure ambient temperature remains within 0 to 55 °C
• Use shielded twisted-pair cables for RTD connections
• Maintain minimum 50 mm clearance between modules for airflow
• Connect redundant backplane cable for PRP configuration
• Ground the shield at one end only (control room end)

Usage Precautions:

• Match input type configuration (S33 = RTD) to actual field sensor before commissioning
• Do not mix RTD and thermocouple inputs on the same module
• Verify 3-wire or 4-wire configuration matches actual field wiring
• Replace both PRP modules simultaneously during scheduled maintenance
• Ensure backup power supply is active for redundant system operation