HES PDB-1R Interface Board Fire Trigger Relay
The HES PDB-1R is a dedicated interface board that translates fire detection signals into access control commands, enabling synchronized emergency response across integrated security systems. Designed for commercial installations where fire alarm and access control must coordinate in real time—unlocking doors, triggering alerts, or silencing card readers during fire events—the PDB-1R handles the relay logic that keeps life safety separate from security convenience.
Key Features
- Fire-to-Access Relay Bridge: Accepts fire trigger inputs and outputs relay commands to unlock mechanisms, disable readers, or activate auxiliary devices. Eliminates the need for manual override during emergency egress.
- 24VDC Operation: Standard building automation voltage. Integrates cleanly with fire alarm panels and HES access control architecture without additional power distribution.
- ULC-S533/S318 Enclosure Approved: Meets Canadian life-safety certification standards for fire alarm system integration. Professional installers can specify with confidence in regulated environments.
- Relay-Based Integration: No proprietary protocols—dry relay contacts work with any fire panel, access control system, or auxiliary device. Reduces vendor lock-in and simplifies cross-platform troubleshooting.
- Multi-System Event Coordination: Single input can trigger cascading relay outputs—e.g., unlock exit doors, silence card readers, alert the NVR to switch to full-frame-rate recording, all from one fire sensor signal.
- Compact Form Factor: 0.35 lb board fits standard equipment racks and DIN rail mounting for indoor control room installation. Designed for retrofit into existing access control closets.
The PDB-1R operates at the critical junction between life safety and security systems. During normal operation, access control enforces tenant isolation and audit trails. When a fire alarm signal arrives, the relay interface overrides those policies: requested exit doors unlock, card readers go offline, and emergency lighting circuits activate. This separation of concerns—fire logic in the fire system, access logic in the access system, integration in the PDB-1R—is the proven pattern for avoiding accidental lockouts or delayed egress.
Installation requires dry relay contacts from the fire panel (typically a conventional fire alarm loop or a programmable output) and relay outputs wired to the access control system's input terminals. HES systems recognize these relay closures as 'force unlock' or 'alarm input' events depending on the access control configuration. The board itself draws negligible current; 24VDC backplane power from the host control panel is the only requirement. No additional UPS or 120VAC outlet is needed.
Compliance with ULC-S533 (fire alarm system integration) and ULC-S318 (Canadian security system standards) means the PDB-1R clears building code review and fire marshal inspection in regulated sectors—hospitals, long-term care, multi-tenant office. US-manufactured, the board uses standard relay technology (no firmware, no licensing fees) and is supported by the HES channel through standard spare-parts logistics.
Marty AllisonPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
We've installed the PDB-1R in everything from medical office parks to data centers, and it remains one of the simplest, most bulletproof fire-to-access bridges in the market. The core strength is architectural clarity: it does one job (relay fire signals to access control outputs) and does it without proprietary firmware or cloud dependencies. On a recent retrofit at a 12-story office tower, we replaced a failed access control system's integrated fire module with a PDB-1R and the existing fire panel—saved the integrator $8k in panel reprogramming and gave the building's fire marshal confidence that the fire logic stayed in the fire system. The relay-based design also means troubleshooting is transparent: trace the wire, check the relay, confirm the output. No middleware, no protocol handshake failures at 3 a.m. The ULC-S533 and S318 approvals are real gatekeepers in Canada and regulated US facilities; if your project is in a medical or government building with strict fire-life-safety review, this board passes inspection without exception. Trade-off: the PDB-1R is strictly relay logic—no IP connectivity, no advanced analytics, no integration with modern IP access control systems. If your customer is moving to cloud-native or IP-based fire integration, this is a legacy-bridge tool. But for sites with hardwired fire panels and traditional access control (which is still the majority of installs), the simplicity and rock-solid reliability make it the pragmatic choice over more complex integration schemes.
Technical Highlights:
- 24VDC Backplane Power: Draws less than 50mA; integrates into existing fire panel or access control 24VDC supply without oversizing. No additional transformer or power conditioning required.
- Dry Relay Contacts: Input accepts any dry closure (conventional fire loop, programmable relay output, door sensor, pushbutton). Output relays are rated for access control solenoid loads (typically 200–500mA @ 24VDC). Field-proven across Schlage, Salto, HID, and legacy electromechanical systems.
- ULC-S533 / S318 Certification: Meets Canadian Standards Association fire alarm and security integration rules. Clears inspections in regulated sectors without exemption or variance request. US-manufactured enclosure sourcing keeps lead times predictable.
- No Firmware, No Cloud: Relay logic is hard-wired; no software updates, no licensing keys, no cloud dependency. Operates even if your network is offline or your VMS is down—pure hardware failsafe.
- Compact Indoor Mounting: 0.35 lb form factor fits in access control closets or equipment racks. Standard 24VDC and relay control wiring; no special cabling or fiber runs.
Deployment Considerations:
- Verify fire panel output type (dry relay vs. voltage output) before wiring. The PDB-1R accepts dry closures; if your fire panel only provides a voltage output, you'll need an external relay module to convert.
- Test the fire trigger path in the fire system's loop test before handing off to the access control team. A missed fire signal can delay emergency egress; verify end-to-end during commissioning.
- Wire the relay outputs to the access control system's designated emergency input terminals (often labeled 'Fire', 'Alarm', or 'Force Unlock'). Confirm polarity and contact rating with the access control panel's wiring diagram.
- Power the PDB-1R from a backed-up 24VDC source (the fire alarm panel's supply or a dedicated emergency battery) so the relay interface stays live during a mains power outage.
- Label relay inputs and outputs clearly in the equipment rack. Future troubleshooting will assume someone knows which fire sensor or access reader is on which terminal.
The PDB-1R is the right choice for integrators and facility managers who prioritize simplicity, regulatory compliance, and long-term reliability over feature count. If your building has a hardwired fire system, traditional access control, and a need for coordinated emergency response, this board eliminates complexity and passes inspection. For more details on HES integration standards and related interface modules, visit the HES catalog.
