Technical Specifications:

• Number of Channels: 2 channels (S2)
• Output Type: Relay contacts (SPDT — Single Pole Double Throw)
• Contact Rating: 250 VAC 3 A (resistive) / 30 VDC 3 A (resistive)
• Contact Material: AgNi (Silver-Nickel alloy)
• Operating Voltage (Coil): 24 VDC
• Insulation: Channel-to-channel isolation, channel-to-bus isolation
• Insulation Resistance: ≥100 MΩ at 500 VDC
• Dielectric Strength: 1500 VAC for 1 minute
• Mechanical Life: 10,000,000 operations (minimum)
• Electrical Life: 100,000 operations (at rated load, resistive)
• Operating Temperature: 0°C to +55°C
• Power Supply: 24 VDC (bus-powered from DCS backplane)
• Mounting: DIN rail or DCS card cage (Yokogawa specified)
• Dimensions: 25 mm × 120 mm × 120 mm (W × H × D)

Functional Features:

• 2 independent SPDT relay outputs
• Dry-contact (voltage-free) outputs — compatible with any voltage/current within rating
• Channel-to-channel isolation — prevents crosstalk
• LED status indicator per channel (energized / de-energized)
• Hot-swappable in DCS card cage
• Fast response time: ≤10 ms (coil energize to contact change)

Material Composition:

• Housing: Flame-retardant ABS resin (UL94 V-0)
• Relay: Sealed electromagnetic relay with AgNi contacts
• PCB: Multi-layer FR-4 with conformal coating
• Connectors: Yokogawa proprietary 96-pin DCS backplane connector

Structural Characteristics:

• Form Factor: DCS I/O card module
• Width: 25 mm (half-width Eurocard)
• Height: 120 mm
• Weight: Approximately 150 g

Working Principle:
The DCS controller sends a 24 VDC command signal via the backplane bus to the RB301-S2 module. The module’s internal driver circuit energizes the electromagnetic relay coil, causing the SPDT contacts to change state (from Normally Open to Normally Closed or vice versa). The dry contacts are then available to switch external circuits (alarm horns, solenoid valves, indicator lights, interlocks). Each of the 2 channels operates independently with full electrical isolation.

Key Advantages:

• Dry-contact outputs — universal compatibility with any external device
• 250 VAC 3 A rating — handles most industrial loads
• 10 million mechanical operations — extremely long service life
• Full DCS integration — native CENTUM VP/CS compatibility
• Hot-swappable — zero downtime for module replacement

Applicable Industries:

• DCS-based safety interlocks (Yokogawa CENTUM VP/CS)
• Oil & Gas (ESD systems, pump interlocks)
• Chemical & Petrochemical (alarm annunciation)
• Power Generation (turbine protection, boiler interlocks)
• Manufacturing (machine control)

Installation Requirements:

• Install in Yokogawa DCS card cage with specified backplane
• Wire external loads to screw terminals (AWG 22–14)
• Do not exceed contact ratings: 250 VAC 3 A / 30 VDC 3 A
• Configure relay logic in DCS engineering software (System View)

Usage Precautions:

• Do not switch inductive loads (motors, solenoids) without snubber/suppression circuit
• Maximum switching voltage: 250 VAC / 30 VDC — do not exceed
• Use appropriate wire gauge for contact current rating
• Do not hot-swap without following Yokogawa DCS procedure