Altronix ACM4CB 4-Output Access Power Controller
The Altronix ACM4CB is a multi-output power distribution and switching device that takes a single 12 to 24 VAC or VDC input and converts it into four independently controlled outputs, each rated at 2A and protected by PTC-resettable fuses. This solves a common deployment pain point: managing power to multiple access control devices (magnetic locks, electric strikes, door holders) from one centralized source without complicated relay wiring or undersized power chains.
Key Features
- Four Independently Controlled Outputs: Each output is isolated and controlled separately—you can energize locks on different doors on different schedules without crosstalk. Maximum system load is 10A total, with 2A per channel, so you won't accidentally overload a single line if one device draws more than expected.
- PTC Auto-Reset Protection Per Output: Instead of traditional fuses that require replacement, each output uses a resettable thermal fuse that trips during fault conditions and re-engages once the fault clears. Reduces field service calls and parts inventory.
- Configurable Trigger Inputs: Accepts dry contact (normally open) or open collector sink signals from access control panels, card readers, keypads, and motion sensors. No special interfaces required—standard dry contact logic works directly.
- Fail-Safe and Fail-Secure Modes Per Output: Configure each of the four outputs independently—some doors can default to unlocked on power loss (Fail-Safe for emergency egress), while others remain locked (Fail-Secure for high-security zones) on the same board. This flexibility eliminates the need for separate controllers in mixed-security deployments.
- Fire Alarm / FACP Integration: Each output can be individually configured to disconnect on fire alarm activation. Supports both normally open and open collector input logic from fire alarm control panels, ensuring emergency egress compliance without additional wiring logic.
- Four Unswitched Auxiliary Power Outputs: Provides continuous 12–24V power for auxiliary devices (sensors, indicators, card readers) independent of the switched relay outputs. Useful when you need some devices powered all the time and others switched by access events.
- Status Indication: LED indicators show input voltage presence and relay activation state for each output—helps troubleshoot wiring and configuration issues on-site without a multimeter.
Integration & Compatibility
The ACM4CB accepts input from any standard access control system that provides dry contact or open collector outputs—no proprietary interfaces. The board supports both single power source designs (one 12–24V supply feeding the controller) and dual isolated supply setups (one supply for board logic, another for lock/accessory loads), giving you flexibility in power architecture depending on system-level redundancy needs.
Board dimensions measure 5.175" × 3.36" × 1.25" (131.4 mm × 85.3 mm × 31.8 mm), making it compact enough for wall-mount DIN rail installation in electrical enclosures or equipment cabinets. Operating temperature range of 0°C to 49°C (32°F to 120°F) covers standard indoor and uninsulated outbuilding environments; if you need extended cold weather operation, verify your power supply specification before deployment.
Certifications & Standards
UL294 listed and cUL certified to CSA C22.2 No. 205-M1983—the relevant safety standards for access control power supplies. This certification confirms the board meets electrical safety and Class 2 power delivery requirements for North American deployments. Lifetime Limited Warranty.
When to Choose a Different Model
If you need more than four outputs or higher current per output, consider higher-capacity models in the Altronix access power family. If your deployment requires integrated battery backup or UPS functionality, you'll need a separate backup supply paired with this controller. For applications requiring field-programmable logic or networked monitoring, investigate whether an access control panel with integrated power distribution might consolidate your bill of materials.
Frequently Asked Questions
Q: Can I mix 12V and 24V devices on the same ACM4CB?
A: The ACM4CB output voltage matches the input voltage—if you supply 12V in, all four outputs deliver 12V out. You cannot create mixed-voltage outputs on a single board. If you need both 12V and 24V devices, you'll require two separate power supplies and controllers, or select a different distribution architecture.
Q: Does the ACM4CB support battery backup or UPS input?
A: The ACM4CB is a power distribution controller only; it has no built-in battery or backup logic. Pair it with a separate UPS or backup power supply if your application requires uninterrupted power during mains failure.
Q: What happens if one output's load exceeds 2A?
A: The PTC fuse on that output will trip (auto-reset), cutting power to prevent damage. Once the overload fault is cleared, the fuse will reset automatically. Ensure your lock and accessory specifications do not exceed 2A per output during normal operation.
Q: Is the ACM4CB suitable for outdoor mounting?
A: The board itself is not sealed; it requires installation in a weatherproof enclosure if exposed to rain or direct sunlight. Verify the enclosure maintains the operating temperature range (0°C to 49°C) for reliable operation in your climate.
Q: Can I daisy-chain multiple ACM4CB units?
A: Yes. Each board operates independently from the same or different power supplies. If you need eight outputs, deploy two ACM4CB units in series with their trigger inputs wired in parallel to your access control panel.
Q: What's the difference between Fail-Safe and Fail-Secure mode on the ACM4CB?
A: In Fail-Safe mode, the output de-energizes if power is lost, unlocking the door for emergency egress. In Fail-Secure mode, the output remains energized even during power loss (via mechanical latching), keeping the door locked. The ACM4CB lets you select either mode per output, so a single board can control both locked and unlocked emergency exits.
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The Altronix ACM4CB fills a genuine gap in multi-door access deployments: independent per-output control without relay switching complexity or undersized power lines. On mid-size to large installations (8–16 doors), this board replaces half a dozen tangled relay modules and eliminates the finger-pointing when one device trips a shared fuse. The 2A per output limit is real, so verify your strike currents beforehand—a heavy-duty electronic strike can draw 1.5–2A, and you won't have headroom for an auxiliary buzzer on the same line.
Technical Highlights:
- PTC Auto-Reset Fuses: No replaceable fuses means fewer parts to carry and faster recovery from temporary overloads. A sympathetic fault—say a shorted door holder—won't leave you hunting a blown component in a dark electrical closet.
- Per-Output Fail-Safe/Fail-Secure Selection: Eliminates the need to deploy separate boards for emergency egress zones (Fail-Safe) and secure zones (Fail-Secure). Single board, eight relay modes possible across four outputs—saves space and simplifies integration testing.
- Four Unswitched Auxiliary Outputs: Continuous 12–24V feed for card readers, LED indicators, or motion sensors independent of the switched relay circuit. Prevents nuisance dropout of auxiliary systems when the main lock relay cycles.
- Class 2 Rating & UL294 Certification: Officially safe for access control use per North American electrical code—no exceptions, no caveats. If your jurisdiction requires third-party certification, this board delivers it out of the box.
Deployment Considerations:
- Input voltage must be stable 12–24V (AC or DC). If your supply drifts below 12V, the board may not latch properly or relays may chatter. Budget for a regulated power supply in your enclosure, not a raw transformer tap.
- Watch the 10A total system limit. Four outputs at 2A each = 8A typical draw, but peaks during simultaneous lock energization. If your application requires all four locks open at once (e.g., emergency override), verify your supply can sustain 10A without sagging below 12V—undersized supplies cause relay dropout and resets.
- Board dimensions and DIN rail footprint are tight; ensure your access control panel enclosure has sufficient space and clearance for terminal block wiring before you order. Cramped installs lead to field rework and callbacks.
Best deployment fit: mid-to-large multi-door access control installations where you need independent per-door power control, mixed Fail-Safe/Fail-Secure logic, and bulletproof UL-certified distribution without relay complexity. Avoid if your application demands more than four outputs, per-output current exceeding 2A, or integrated battery backup—those require a different architecture.
