Honeywell 51120841-101 SPDT Control Relay Module

Honeywell 51120841-101 SPDT Control Relay Module

The Honeywell 51120841-101, also cataloged as the MR Series SPDT relay module, operates as a single-pole, double-throw control relay for discrete signal switching in Honeywell system architectures.

Hardware Specifications

Galvanic Isolation and Fail-Safe Execution

The 51120841-101 relay module provides galvanic isolation between coil control voltage and switched contacts, ensuring safe separation of logic and field circuits. In fail-safe configurations, the SPDT contact arrangement supports deterministic switching to default states, maintaining system integrity under fault conditions.

Frequently Asked Questions (FAQ)

Q: What is the maximum current rating of the relay contacts? A: The contacts are rated at 10 A for 250 VAC and 10 A for 30 VDC.

Q: Does the module include a status indicator? A: Yes. A built-in red LED illuminates when the coil is energized.

Q: What mounting options are supported? A: The module supports DIN rail, track-mounting, or panel installation.

Field Installation Guidelines

• Mount the relay module securely on DIN rail or panel tracks with proper mechanical engagement.
• Ensure coil voltage wiring matches the specified operating range (18–30 VDC or AC variants).
• Use shielded wiring for control circuits, grounding shields at the system end only.
• Separate relay wiring from high-current conductors to minimize interference.
• Verify contact polarity and load ratings before energizing.
• Maintain ambient conditions within specified operating temperature limits.