Honeywell 24VDC Fail-Safe Output Module FS-SDO-0424

Honeywell FS-SDO-0424 Fail-Safe Digital Output Module

The Honeywell FS-SDO-0424 is a de-energize-to-safe digital output module designed for the most demanding safety applications. With 4 high-current channels at 24VDC, this module ensures failsafe operation in critical control systems where reliability and safety are paramount.

Core Specifications

• Brand: Honeywell
• Model: FS-SDO-0424
• Product Type: Fail-Safe Digital Output Module
• Safety Philosophy: De-energize-to-safe (positive-driven safety)
• Number of Channels: 4 Channels
• Output Voltage: 24 VDC nominal (18-30 VDC range)
• Output Current: 2.0 A per channel continuous

Electrical Characteristics

• Output Type: Electromechanical safety relay with forced-guided contacts
• Contact Configuration: 4 normally open (NO) safety contacts
• Contact Material: Silver alloy with gold plating
• Maximum Switching Power: 48 W per channel (24VDC @ 2A)
• Minimum Switching Current: 10 mA for reliable contact wetting
• Maximum Inrush Current: 15 A for 20 ms (inductive loads)
• Contact Resistance: < 30 mΩ (new, at 1A)

Safety Performance Metrics

• Safety Integrity Level: SIL 3 (IEC 61508)
• Performance Level: PL e (ISO 13849-1)
• Category: 4 (EN ISO 13849-1)
• Hardware Fault Tolerance: 1 (HFT=1)
• Diagnostic Coverage (DC): ≥ 99%
• PFH Value: < 5×10⁻⁹ per hour
• MTTFd (Mean Time to Dangerous Failure): > 150 years

Isolation & Protection

• Isolation Voltage: 1500 V AC (contact to coil, contact to contact)
• Dielectric Strength: 3500 V AC for 1 second (impulse withstand)
• Creepage Distance: > 10 mm
• Clearance Distance: > 8 mm
• Surge Immunity: 2 kV (IEC 61000-4-5, line-to-line)
• Overvoltage Category: III per IEC 60664-1
• Pollution Degree: 3

Timing & Switching Performance

• Operate Time (Pick-up): ≤ 8 ms (at nominal voltage)
• Release Time (Drop-out): ≤ 5 ms
• Bounce Time: < 2 ms
• Mechanical Life: > 10⁷ operations (no load)
• Electrical Life: > 10⁵ operations at rated load
• Maximum Switching Frequency: 10 Hz (at rated load)

Diagnostic & Monitoring Features

• Contact Monitoring: Real-time contact position feedback
• Coil Monitoring: Continuous coil circuit integrity check
• Temperature Monitoring: Embedded thermal sensor with overtemperature shutdown
• Forced-Guided Contact Verification: Mechanical linkage ensures NO/NC synchronization
• LED Indicators: Per-channel status (green=energized, red=fault)
• Fault Memory: Last 10 faults stored with timestamp

Power Requirements

• Coil Voltage: 24 VDC ±20%
• Coil Power Consumption: 1.8 W per channel (energized)
• Inrush Current (Coil): 3 A for 50 ms per channel
• Hold Current: 75 mA per channel
• Backplane Power: 5 VDC @ 200 mA maximum
• Total Module Power: ≤ 15 W maximum (all channels energized)

Environmental Specifications

• Operating Temperature: -40°C to +70°C (full performance)
• Storage Temperature: -55°C to +85°C
• Altitude Rating: 5000 meters without derating
• Vibration (Operational): 5-500 Hz, 3.0 G
• Shock (Operational): 50 G, 11 ms
• Relative Humidity: 0-100% condensing
• Corrosion Resistance: Salt fog tested per IEC 60068-2-52

Mechanical Specifications

• Module Dimensions: 125 × 85 × 120 mm (H × W × D)
• Weight: 450 grams
• Mounting: DIN rail EN 60715 TH35-7.5 or TH35-15
• Terminal Type: Screw terminals with cage clamp
• Wire Range: 0.5-4.0 mm² (AWG 20-12)
• Terminal Torque: 0.6-0.8 Nm
• Agency Spacing: 50 mm left/right for heat dissipation

Compliance & Certifications

• Safety Standards: IEC 61508, IEC 62061, ISO 13849-1
• EMC: EN 61326-3-1 (safety-related equipment)
• Safety Certifications: TÜV Rheinland SIL 3, exida certified
• Hazardous Area: ATEX/IECEx Ex ia IIC T4 Ga
• Marine: DNV-GL, LR, ABS, BV (full maritime package)
• Seismic: IEEE 693 (high performance level)