Altronix AL600ULB 12VDC/24VDC 6A Timer/Relay Module
The Altronix AL600ULB is a board-level timer/relay module that converts 28VAC input into selectable 12VDC or 24VDC output at up to 6 amps. It integrates AC mains monitoring and sealed lead acid or gel-type battery backup support, making it a practical power-conditioning solution for access control systems, fire alarm circuits, and other security devices that require uninterrupted DC supply during mains failure.
Key Features
- Selectable Output Voltage: Choose 12VDC or 24VDC via onboard jumper — eliminates the need to stock two separate modules and lets you match downstream device requirements without redesign.
- 6A Maximum Output Current: Delivers enough power for multiple low-draw devices (door locks, access readers, siren drivers) on a single module. Verify the sum of connected device currents stays below 6A to avoid nuisance shutdowns.
- 28VAC Input: Accepts standard transformer-based AC supplies, which are common in legacy and new installations. Input voltage tolerance is tight, so measure your transformer output before deployment.
- AC Fail and Battery Presence Supervision: Built-in status signals detect when mains power drops and whether a battery is connected — essential for UL-listed fire alarm and access control systems that require fault reporting to a central station or local annunciator.
- Fire Alarm Disconnect Capability: Supports supervised disconnect of fire alarm circuits per UL1481 — a critical safety feature for systems that must de-energize locks or solenoids during alarm conditions.
- Single Relay Output: One SPDT relay allows switching auxiliary loads or signaling downstream controllers. Load current is independent of the 6A DC output limit, but verify the relay's contact rating for your intended load.
- UL294 (Access Control) and UL1481 (Fire Alarm) Certifications: These certifications mean the AL600ULB meets safety and reliability standards for monitored security circuits — a requirement for any system that ties into a UL-listed control panel or central station monitoring.
- Battery Backup Support: Sealed lead acid or gel-type batteries (sold separately) keep DC output alive during AC loss. Size the battery based on load current and desired backup duration — a 12Ah battery will run a 2A load for roughly 6 hours.
- Wide Operating Temperature Range: Rated 0°C to 49°C (32°F to 120°F), so it tolerates unheated closets, outdoor enclosures with weather protection, or heated utility rooms. Below 0°C or above 49°C, performance is not guaranteed.
- Compact Board Form Factor: Measures 7.1" × 4.3" × 2.3" (180.3mm × 109.2mm × 58.4mm), fitting easily into standard 2U or larger DIN-rail-mounted power enclosures alongside related modules.
Integration & Compatibility
The AL600ULB is a passive power-conditioning module — it does not require software setup, IP addressing, or integration with a VMS. It mounts on DIN rail and wires directly to a 28VAC transformer input and DC load circuits. The relay output and supervision signals connect to access control or fire alarm control panels via simple terminal blocks. This makes it suitable for installations where a dedicated power supply module is needed without adding network complexity. Verify your battery type matches Altronix specifications before purchase; incompatible battery chemistries may damage the module or fail to charge properly.
When to Choose a Different Model
If you need higher output current (above 6A), consider a higher-amperage power supply in the Altronix power supply line. If you require integrated surge protection or status LEDs for quicker troubleshooting, check for Altronix modules with those features. For non-UL-listed applications or where battery backup is optional, a simpler non-supervised AC/DC converter may reduce cost.
Frequently Asked Questions
Q: What battery types does the AL600ULB support?
A: The module is compatible with sealed lead acid and gel-type batteries sold separately. Do not use lithium-ion or other battery chemistries unless explicitly approved by Altronix, as they may overcharge or fail to accept charge properly.
Q: What is the warranty on the AL600ULB?
A: Altronix provides a Lifetime Limited Warranty covering defects in materials and workmanship.
Q: Can I use the AL600ULB without a battery?
A: Yes. The module will condition and output 12VDC or 24VDC from the 28VAC input without a battery installed. However, if you need AC Fail supervision (a requirement for UL-listed systems), a battery must be present so the module can signal a mains failure.
Q: What transformer output voltage do I need to power the AL600ULB?
A: The module requires 28VAC input. Measure your transformer's secondary output at full load before wiring; if it drops below 25VAC or exceeds 31VAC, the module may not perform as specified.
Q: Is the AL600ULB suitable for fire alarm applications?
A: Yes. The module carries UL1481 certification and includes fire alarm disconnect capability, making it compliant for use in monitored fire alarm circuits.
Jerry TildsenPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The AL600ULB is a workhorse module for any access control or fire alarm install that needs clean, supervised DC power with battery backup. The fact that it handles both 12VDC and 24VDC output via a simple jumper change means you can keep a single SKU on the shelf instead of maintaining two separate part numbers — that alone saves integration time and inventory headaches.
Technical Highlights:
- 6A Output at Selectable Voltage: Whether you need 12VDC or 24VDC, the AL600ULB delivers the same 6A maximum, so you're not forced to choose between voltage flexibility and current capacity. Real-world benefit: one module supports 4–6 proximity readers, door controllers, and low-draw solenoids simultaneously without chaining power supplies.
- AC Fail and Battery Presence Supervision: Both signals are supervised, meaning a central station panel knows instantly if mains drops or a battery disconnects. This is non-negotiable for any UL-listed fire alarm or access control circuit; without it, a dead battery or unplugged transformer goes undetected until someone tries to use the door lock.
- UL294 and UL1481 Dual Certification: These aren't cosmetic badges. They mean Altronix tested this module against access control AND fire alarm safety standards. You can deploy the same module in either application without worrying about secondary approvals.
Deployment Considerations:
- Input Voltage Tolerance is Tight: The module expects 28VAC ±3V, which is narrower than some transformers tolerate under full load. Always measure your transformer output with the full connected load running before you close the panel. A sagging transformer can drop below 25VAC, and the module will not regulate properly.
- Battery Sizing Requires Calculation: The Altronix documentation doesn't ship with a ready-made battery selection chart, so you must size your sealed lead acid battery based on connected load current and desired backup duration. A 12Ah battery backing a 2A load gives roughly six hours of autonomy. Under-size the battery and you lose backup. Over-size it and you're paying for capacity you won't use and charging time you don't need.
- Relay Output Load Is Independent of DC Output Current: This is a common gotcha. The relay can switch loads up to its contact rating (typically 10A at 24VDC), but that load does NOT count against the 6A DC output limit. However, if the relay drives a solenoid or lock that also draws from the DC supply, you must account for both the relay's coil current and the device current when sizing your transformer and battery.
Deploy the AL600ULB in any monitored access control or fire alarm enclosure where you need reliable, battery-backed DC power from standard 28VAC transformer input. It's especially valuable in retrofit projects where existing 28VAC transformers are already in place — saves cost over installing new transformer and power supply combinations. For new greenfield installs with multiple power zones, the selectable voltage feature lets you standardize on one module family across the entire site.
