HES 10306LA Current Transmitter Two-Leaf Door/Window

We've installed hundreds of HES transmitters across institutional campuses, commercial office towers, and industrial facilities, and the 10306LA is one of the cleanest solutions for paired-leaf scenarios. In our experience, the biggest operational win is that you're not wire-tracing two separate transmitters back to two separate inputs on your access control panel — you get one logical monitoring point that handles both leafs. On a university dorm vestibule or a pharmaceutical cleanroom with dual interlocking doors, that consolidation saves engineering time during commissioning and reduces the troubleshooting surface area when a door sensor misbehaves. We've seen integrators make the mistake of using single-leaf transmitters for paired doors and then discovering that their HES logic can't easily enforce "both doors closed before next unlock" without custom programming — the 10306LA bakes that dual-leaf semantic into the hardware, keeping the control panel logic simpler and less prone to commissioning delays.

Technical Highlights:

• Current Transmitter Architecture: HES current transmitters operate by modulating a current loop signal — typically 4–20 mA or discrete contact-closure equivalents depending on the HES controller model. This approach is inherently noise-immune compared to voltage-based signaling, which matters in facilities with heavy inductive loads (motor controllers, HVAC equipment). We've never seen noise-induced false reports on properly terminated HES current loops, even in industrial plants with extensive electromagnetic interference.
• Dual-Leaf Input Consolidation: The transmitter accepts two independent contact inputs (one per leaf) and combines them into a single output state — either "both closed", "one open", or "both open". HES controllers then interpret that combined state to enforce your specific interlock logic. No external relay logic or software translation needed.
• Real-Time Status Delivery: State changes propagate through the HES network at line frequency (60 Hz in North America) — effectively instantaneous for access control purposes. This ensures that if a vestibule door opens unexpectedly, your HES event log captures the exact moment and your interlock logic can respond (lock the inner door, trigger an alarm, etc.) without perceptible lag.
• US Manufacturing: Built domestically by HES, which means spare transmitters are typically stocked in the US supply chain and available for next-day replacement. We've worked with integrators managing 500+ card readers across a state university system, and HES's domestic fulfillment meant zero downtime due to parts scarcity — a significant operational advantage compared to overseas suppliers with 8–12 week lead times.
• Weight and Form Factor: At 2 lb, the 10306LA is sized for either cabinet mounting or small enclosure integration. On warehouse installations where we've had to retrofit transmitters into existing conduit runs or DIN-rail spaces, the compact footprint has consistently fit without re-engineering the panel layout.

Deployment Considerations:

• Contact Input Polarity: HES current transmitters require proper contact closure polarity on each leaf input. During installation, verify that both door/window sensors provide normally-open contacts (or configure jumpers on the transmitter for normally-closed if required). A backwards contact polarity will be obvious during testing, but catching it in your pre-commissioning checklist beats a post-handoff callback.
• Cable Run Distance: Current-loop wiring can span 500+ feet without signal degradation — important for distributed campuses or multi-building industrial sites where your doors might be far from the central access control panel. Use standard shielded twisted pair (STP) rated for low-voltage control circuits and terminate shield at the controller end only to avoid ground loops.
• Paired-Leaf Logic in HES Controller: The transmitter reports combined state, but the controller's response depends on how you program it. For true interlock ("don't unlock the inner door until the outer door closes"), you'll need to configure that logic in HES software or hardware relay configuration — the transmitter itself is passive. Spend time in the commissioning phase defining your interlock sequence with the facility team so HES logic matches physical security intent.
• Integration with HVAC/Fire Systems: In facilities where HVAC or fire safety also needs to know door state (e.g., maintain pressure differential in a cleanroom), you may need to tap the HES current loop signal and feed it to a secondary system. This is straightforward if your fire/HVAC system accepts 4–20 mA input, but coordinate beforehand to avoid double-wiring doors.
• Maintenance Access: The 10306LA lives in your access control cabinet or a field-mounted enclosure. Ensure that technicians can access it without disassembling critical wiring. On some installations we've seen, a poorly labeled or inaccessible transmitter led to 20-minute troubleshooting calls that could have been 2-minute swaps. Label your cabinet clearly and provide spare transmitters on-site for facilities where downtime is expensive.

The 10306LA is the right choice for integrators and facility teams already committed to HES access control who need to monitor paired doors or windows without fragmenting their architecture. If your facility has vestibules, interlocking doors, dual loading docks, or any paired-leaf configuration, this transmitter eliminates the confusion of managing multiple monitoring points and keeps your HES event logs coherent. Explore the full HES catalog for other transmitters, controllers, and credential readers that integrate with this core component.