Altronix SMP312CX Board-Mount Power Supply Charger
The Altronix SMP312CX is a compact board-mount regulated power supply designed for integration into security, access control, and surveillance systems requiring 24/7 availability and battery backup support. This unit accepts flexible AC input (12–28VAC) and provides selectable DC output voltages, making it suitable for retrofit and new-build deployments where space and voltage flexibility are constraints.
Key Features
- Selectable Output Voltage (6VDC, 12VDC, or 24VDC): Choose the exact voltage your downstream device requires — eliminates the need to stock multiple PSU models for different control circuits, access readers, or sensor modules. Configured at installation time.
- Input Range 12–28VAC: Accepts transformer or wall-power secondary voltage without additional conditioning. Covers both standard 24VAC (common in HVAC and control cabinets) and lower-voltage AC feeds, reducing dependency on a single source.
- 0.5A Maximum Output Current: Sufficient for auxiliary circuits, electronic locks, door strikes, access control readers, alarm panel power modules, and low-power camera backup systems. Do not overload this supply for high-current applications (12W @ 24VDC, 6W @ 12VDC, 3W @ 6VDC); size accordingly for your load.
- Board-Mount Form Factor: Designed for direct integration onto DIN-rail backplanes or embedded within cabinet power distribution boards. Eliminates external enclosure overhead and reduces wiring complexity in constrained spaces.
- Battery Backup Support via BT126 Module: Compatible with Altronix BT126 battery modules for uninterruptible power to critical circuits during AC mains failure. Supports graceful shutdown of access control systems and alarm panels when mains power is lost.
- Single Regulated Output: One DC output with internal regulation ensures stable voltage delivery even as AC input fluctuates across the 12–28VAC range, protecting downstream equipment from voltage sag or transient damage.
- Lifetime Limited Warranty: Manufacturer Warranty covers defects in materials and workmanship, standard for Altronix security-grade power supplies.
Integration & Compatibility
The SMP312CX integrates into power supply and charger architectures where compact, multi-voltage capability is required. It is commonly deployed in access control system cabinets for lock and reader power, in alarm panel auxiliary circuits, and as backup power for low-bandwidth IP cameras and edge recording devices. Consult the datasheet for wiring diagrams, terminal assignments, and battery module pairing guidelines.
When to Choose a Different Model
If your application requires higher output current (e.g., powering multiple door strikes simultaneously or a 24V LED backlight panel), consider a higher-current variant from the Altronix power supply family. If you need integrated surge suppression or DIN-rail enclosure form factor rather than board-mount, evaluate Altronix's standalone cabinet-mounted supplies. For 12VDC-only applications where voltage selection is unnecessary, a fixed-voltage supply may reduce cost and board real estate.
Typical Deployment Considerations
Install the SMP312CX on a DIN-rail or embedded backplane where it has access to clean 12–28VAC transformer output. Ensure AC conductor sizing matches transformer VA rating and electrical code. When deploying battery backup, wire the BT126 module according to Altronix documentation to enable automatic float charging during normal operation and seamless backup discharge during AC loss. Test the backup circuit under load before final commissioning. Do not exceed 0.5A continuous draw on the selected voltage rail; oversizing protection fuses will not compensate for undersized supply current capacity.
Frequently Asked Questions
Q: Can I use the SMP312CX to power both a door strike and an access control reader simultaneously?
A: Only if their combined continuous current draw does not exceed 0.5A at the selected output voltage. A heavy-duty strike (e.g., 1.5A @ 24VDC) will overload this supply; you will need a higher-current model or a dedicated supply for the strike circuit.
Q: Does the SMP312CX include a BT126 battery module?
A: No. The unit supports battery backup via a separately purchased Altronix BT126 module. Order the BT126 if backup power is required.
Q: What is the warranty period for the SMP312CX?
A: Lifetime Limited Warranty, covering defects in materials and workmanship under normal use conditions.
Q: Can the output voltage be changed after installation?
A: Yes, but it requires opening the enclosure and adjusting the selector (typically a jumper or switch on the board). This is a one-time configuration task done during commissioning, not a field-adjustable parameter during operation.
Q: Is the SMP312CX suitable for outdoor or wet-location installations?
A: No. This is a board-mount component designed for installation inside cabinets or on sheltered backplanes. For outdoor or wet-location power applications, use an environmentally sealed enclosure or a dedicated outdoor-rated power supply.
Q: What AC input frequency does the SMP312CX require?
A: The unit operates on standard 50/60 Hz AC. Consult the datasheet for input impedance and transient response characteristics if your AC source is non-standard.
Ted PerryPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The Altronix SMP312CX is a no-frills, space-efficient workhorse for access control and low-power security circuits. The selectable voltage output and broad 12–28VAC input range make it adaptable to retrofit cabinets where standardizing on one PSU model would otherwise require inventory of three separate devices. In 24/7 access control deployments, the 0.5A capacity is the critical constraint — it will power a single electromagnetic strike or a handful of readers, but not both simultaneously at full draw.
Technical Highlights:
- Selectable Output (6/12/24VDC): One board supplies three voltage options, reducing SKU burden in multi-site rollouts. Avoids the cost and space penalty of having separate 6V, 12V, and 24V supplies on the shelf.
- 0.5A Maximum Current: Do the math upfront: a 24VDC output maxes out at 12 watts. A typical electronic strike draws 0.6–1.2A, meaning you cannot run a strike alone on this supply. Size a larger model if strike + reader power is both required on one circuit.
- 12–28VAC Input Range: Covers both transformer secondaries and direct line supplies. Regulatory voltage swings in real buildings (overvoltage during light load, sag during heavy load) stay within this window, so the SMP312CX regulates without dropout.
Deployment Considerations:
- This is a board-mount component — it goes inside a cabinet, not in an outdoor box. Plan for a DIN-rail or embedded PCB mounting during cabinet design. No IP rating; moisture or dust ingress will cause failure.
- Battery backup (BT126) is optional but standard in uninterruptible access control designs. The SMP312CX floats the battery automatically during normal AC operation and switches to backup discharge on AC loss — verify the battery module is ordered separately if you need it.
- Current limit is the real constraint. If your circuit list totals more than 0.5A continuous draw, this supply will not be sufficient. Over-current will not blow a field fuse; it will cause voltage droop and erratic behavior in downstream devices. Size the supply conservatively — never assume peak-to-average load ratio will prevent overload.
Use the SMP312CX when you have multiple low-current auxiliary circuits (readers, keypads, small solenoids, alarm panel power) and voltage flexibility is valuable. Skip it if you need high-current strike power or outdoor/wet-location capability; those require larger or more rugged supplies.
