System Sensor R-20E Single DPDT Relay with EOL

System Sensor R-20E Single DPDT Relay with EOL

Overview

The System Sensor R-20E is a single DPDT (double-pole, double-throw) relay module designed for integration with fire alarm control panels and security automation systems. The R-20E provides relay switching capability with end-of-line (EOL) supervision, enabling reliable control signaling in fire detection and life safety applications. This module serves as an interface between control panels and external devices requiring relay-switched outputs, including door strikes, auxiliary equipment, and visual/audible notification devices.

Key Features

• Single DPDT relay configuration provides two independent contact sets for flexible switching control
• End-of-line (EOL) supervision ensures circuit continuity monitoring and fault detection
• Compatible with System Sensor fire alarm control panels and third-party systems supporting standard relay interfaces
• Dual-channel output capability enables simultaneous control of multiple auxiliary circuits
• Compact form factor suitable for retrofit and new installation applications
• Reliable electromechanical relay design for critical life safety applications
• Standard 24 VDC operation typical for fire alarm systems
• Field-installable module for control panel integration

Integration & Compatibility

The R-20E (commonly searched as R 20E) integrates with System Sensor addressable and conventional fire alarm control panels as an auxiliary relay output module. The module accepts trigger signals from panel zone circuits, notification appliance circuits, or addressable device loops, translating logic commands into DPDT relay switching actions. EOL supervision monitoring provides circuit fault reporting, alerting operators to open or compromised relay output lines. This is particularly valuable in installations where loss of control signal must be detected and logged.

The relay contacts support standard 24 VDC loads typical in life safety systems, including magnetic door strikes, solenoid valve actuators, and external relay banks. Contact rating and switching capacity conform to fire alarm equipment standards, ensuring safe operation in continuous-duty and momentary-switch applications. System integrators can use the dual-pole design to control two independent circuits from a single module, reducing overall panel footprint and wiring complexity.

Typical Applications

Security integrators and fire system installers deploy the R-20E in fire evacuation control systems, where alarm signals trigger door unlock sequences, stairwell pressurization fan control, or emergency lighting circuits. Facilities managers use relay modules in multi-building campuses to coordinate alarm signals across geographically distributed zones. Healthcare facilities integrate the R-20E into nurse call and life safety networks, ensuring alarms trigger appropriate facility automation responses without manual intervention.

Jerry Tildsen

The System Sensor R-20E has proven itself as a reliable, straightforward relay interface in hundreds of fire alarm panel installations I've coordinated. Its DPDT configuration and EOL supervision make it an economical choice when you need dual-channel switching with circuit continuity assurance. The R-20E integrates seamlessly into conventional System Sensor panels and provides the contact isolation necessary for driving external 24 VDC loads.

Technical Highlights:

• DPDT Relay Contact Configuration: Two independent contact pairs (NO and NC) from a single coil, allowing simultaneous control of separate circuits or cross-switching logic
• EOL Supervision: Built-in end-of-line monitoring detects open or shorted relay output lines, reporting faults to the control panel for operator awareness and audit compliance

Deployment Considerations:

• Verify control panel compatibility before ordering—the R-20E is designed for System Sensor panels; confirm your specific panel model supports auxiliary relay modules
• Plan wiring runs to external loads (door strikes, solenoids) with adequate gauge conductor sizing; verify load voltage and current requirements are within 24 VDC relay contact ratings
• During commissioning, test EOL circuit with a resistor across the supervised pair to confirm panel receives and logs fault signals when the loop is opened
• Position the module in the control panel enclosure away from high-voltage wiring and ensure proper grounding of the panel chassis to prevent supervisory circuit noise

For integrators working in large multi-tenant or multi-zone facilities, the dual-pole design allows you to reduce overall module count by combining two simple switching operations into one R-20E. This approach cuts panel real estate demand and simplifies maintenance documentation. Ensure EOL circuit is terminated with the correct resistor value specified by your control panel manufacturer to avoid nuisance faults during normal operation.