HES RB-4-24 24VDC Relay Board
The HES RB-4-24 is a 24VDC auxiliary relay board designed to expand output switching capacity in HES access control and electric locking deployments. This relay module integrates directly with HES power supplies and control systems, providing additional relay outputs to drive electric door locks, gate operators, and secondary devices across multi-door installations. It mounts in control rooms and equipment racks, enabling system architects to scale beyond the native relay count of primary control modules without replacing core infrastructure.
Key Features
- 24VDC Relay Outputs: Auxiliary switching for electric door locks and ancillary devices. Expands control capacity in access control systems without modifying primary control modules.
- HES System Integration: Native compatibility with HES power supplies and control systems. Eliminates integration complexity and certification risk.
- Rack-Mount Form Factor: Mounts in control rooms and equipment cabinets. Centralizes relay logic in a single point of management and simplifies field troubleshooting.
- Multi-Door Deployment Support: Scales auxiliary switching outputs to support larger facilities. Reduces the need for external relays or additional control modules.
- Straightforward Wiring: 24VDC inputs and outputs work with standard access control wiring practices. No special power conditioning or isolation required.
- Industrial Reliability: Purpose-built for access control environments. Operates in temperature and humidity ranges typical of secure control rooms and locked equipment cabinets.
System Architecture & Integration
The RB-4-24 serves as an output expansion module for HES control ecosystems. In practice, it sits downstream of a primary control module or power supply, receiving control signals over low-voltage switching lines and providing isolated relay contacts to electric locks, solenoids, and status indicators. This architecture is common in multi-tenant or multi-building deployments where a single control room manages access across dozens of doors — the relay board keeps wiring consolidated and eliminates the scatter of small relays throughout the facility.
The 24VDC supply requirement is standard for HES infrastructure, so no separate power conversion is needed. Integrators should confirm that the primary HES power supply has sufficient capacity (amps) to drive both the control module and any relay boards in parallel; on most commercial systems, a single 24VDC/5A supply can support one control module and one or two relay boards without issues. Datasheet review and site load calculation are essential before deployment.
Deployment Considerations & ROI
The RB-4-24 is cost-effective for expanding control in existing HES installations without replacing the entire control stack. If a facility outgrows the native outputs of the primary control module (a common scenario as tenants add doors or access zones), adding a relay board is faster and cheaper than swapping the control module itself. For integrators managing service contracts, a stocked RB-4-24 or two allows quick capacity upgrades on-site, minimizing downtime and call-back cycles. Total installation time is typically 30 minutes — mount the board, wire the control signal and 24VDC, and terminate the lock circuits to the relay contacts.
Environmental resilience is adequate for indoor control rooms and secured equipment racks; the board is not rated for outdoor or high-humidity (>95% RH) enclosures. Installers in damp or corrosive environments (e.g., parking-garage control rooms, salt-air proximity) should mount the RB-4-24 in a NEMA 4X or better enclosure to extend service life.
Compliance & Support
The RB-4-24 is manufactured in the United States and carries no NDAA or Section 889 restrictions. It works exclusively within HES control ecosystems, so interoperability testing is limited to HES-branded power supplies and control modules. Documentation and wiring diagrams are available in the product datasheet; for integration into custom or legacy HES installations, contact HES technical support to confirm module revision and control signal compatibility. When properly configured, the RB-4-24 integrates transparently — no special drivers, middleware, or recertification of the primary control module is required.
Marty AllisonPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
We've specified the HES RB-4-24 on dozens of access control projects over the past eight years, and it remains one of the most practical capacity-expansion modules in the HES product line. The board solves a real architectural problem: a facility manager calls their integrator to add five new doors to an existing two-door HES system, but the primary control module is at relay-output capacity. Rather than rip out the whole control stack — which means reprovisioning power supplies, rewiring sensor inputs, and re-testing the entire installation — a relay board drops in downstream, uses the existing 24VDC infrastructure, and adds the outputs you need in an afternoon. On large deployments (50+ doors split across multiple control rooms), we typically see one relay board per control module, sometimes two. The module is not intelligent; it's just clean relay switching, which is exactly what you want in a supporting component.
Technical Highlights:
- 24VDC Supply Compatibility: Works with any HES-branded 24VDC power supply rated 5A or higher. No power conditioning, no isolation transformers needed. Standard amps calculation: each relay typically draws 50–150mA when pulled; a single supply usually accommodates control module + one relay board without upgrade.
- Isolated Relay Contacts: Each relay output is galvanically isolated from the control signal, preventing ground-loop noise from corrupting access system logic. Critical in multi-door installations where lock circuits run across long conduit runs (100+ feet).
- Modular Expansion Path: Unlike monolithic control modules with fixed outputs, the RB-4-24 lets you add relay capacity without replacing the primary control unit. Scales the system without throwing away the installer's existing configuration and testing investment.
- US Manufacture: Built in the United States, no supply-chain volatility, and straightforward technical support through domestic HES channels. Important for organizations subject to NDAA procurement rules.
- No Firmware or Software: Pure electromechanical relay logic. No firmware updates, no compatibility matrix to track, no driver conflicts on the access control PC. Reliability is deterministic.
Deployment Considerations:
- Verify 24VDC supply amp rating before installation. If the existing supply is at 90%+ of rated capacity, a 5A or 10A upgrade is cheaper upfront than an on-site power shortage callback six months later.
- Control signal wiring into the RB-4-24 must use the same gauge and conduit discipline as the primary control module inputs. Do not mix the relay-board wiring with low-voltage data lines (network cables, sensor signal pairs) unless they are shielded or separated by at least 6 inches in the enclosure.
- Test relay coil pull-in voltage and contact voltage drop under full load before handing off to the customer. A marginal 24VDC supply may energize the relay at idle but fail to hold the contact when the lock solenoid draws peak current.
- Mount the RB-4-24 in a metal or NEMA-rated enclosure in field installations, even in 'secure' control rooms. Protects against accidental shorts and extends component life in dusty or temperature-cycling environments.
- Label the relay board clearly in the enclosure. Document which relay output drives which door or device; many field service calls stem from mis-wiring on relay expansions added months or years after the primary installation.
The RB-4-24 is the right choice for any integrator managing a multi-door HES installation that has outgrown its native relay count or anticipates adding doors in the future. It is not suitable for applications requiring remote control signaling (Ethernet, serial, cellular) or for systems that need to integrate third-party (non-HES) hardware on the relay outputs — those scenarios call for a full control module upgrade or an external gateway. For straightforward door count expansion within the HES ecosystem, the relay board is reliable, cost-effective, and fast to deploy. See the HES catalog for compatible power supplies and control modules.
