Altronix AT4 4-Channel Annual Event Timer with Alphanumeric LCD
Overview
The Altronix AT4 is a 4-channel, 365-day programmable timer built for commercial security and building automation applications where precise, reliable relay scheduling is non-negotiable. With an alphanumeric LCD display and support for up to 254 daily/weekly events plus 254 holiday dates, the AT4 handles complex annual scheduling that simpler 7-day timers cannot accommodate. It accepts 12 to 24 VAC or VDC input, making it compatible with a wide range of existing control panels and power supplies without requiring a dedicated transformer. If you're wiring timed access control outputs, gate controllers, lighting circuits, or alarm zone activations into a single programmable unit, the AT4 is purpose-built for that role. Browse the full Altronix security power and control line for complementary products.
Key Features
- 4 Form C Relay Outputs, 10A @ 120VAC/28VDC: Each of the four relay contacts handles up to 10 amps — sufficient to directly switch door strikes, magnetic locks, lighting contactors, or small motor loads without an intermediate relay. That rating covers most commercial access control loads without additional hardware.
- 254 Daily/Weekly Events + 1,778 Weekly Event Capacity: Most commercial installations never approach these limits, but facilities running multi-zone scheduled lighting, HVAC interlocks, and access control simultaneously across four outputs will appreciate the headroom. You won't hit a ceiling mid-deployment.
- 254 Holiday Dates: Program up to 254 specific calendar dates for exception scheduling — school closures, corporate holidays, or special event overrides. This eliminates manual reprogramming before every holiday, a common failure point on simpler weekly timers.
- 12–24 VAC or VDC Input: Dual-voltage, dual-polarity input means the AT4 drops into virtually any existing low-voltage control cabinet. You're not locked into a specific transformer or panel voltage, which simplifies retrofits significantly.
- Battery Backup — 12VDC Sealed Lead Acid or Gel: Relay outputs continue operating through power outages. The onboard charger handles up to 300mA charge current, sized for standard 7Ah or 12Ah SLA batteries. The clock itself uses a separate lithium CR2032 cell, so timekeeping survives even if the main battery is disconnected.
- Alphanumeric LCD Display: Plain-text readout makes programming and verification straightforward for technicians who aren't the original installer. Cryptic icon-only displays are a recurring service call source — the AT4 avoids that.
- -20°C to 49°C Operating Range: Covers unheated mechanical rooms and outdoor enclosures in most North American climates. Not rated for extreme cold environments below -20°C.
- 20mA Standby Current (Relays Off): Minimal draw on the host panel or power supply, relevant when the AT4 shares a supply with other devices on a tight power budget.
Integration & Compatibility
The AT4 fits naturally alongside access control systems, gate operators, and building automation panels that require timed relay outputs. Its Form C contacts (normally open, normally closed, common) integrate with virtually any low-voltage control circuit. The enclosure dimensions (12" x 7.5" x 4.5") accommodate standard rack or wall-mount installations; the board itself measures 7" x 5.5" x 1.2" for panel-mount applications. For facilities also deploying timed security power supplies or access hardware, the AT4 consolidates scheduling without adding a separate controller. Consider pairing with a door controller for sites requiring credential-based override of timed outputs. If you need a structured access control planning guide, that resource covers scheduling architecture for multi-zone facilities.
Frequently Asked Questions
Q: What input voltage does the AT4 accept?
A: The AT4 accepts 12 to 24 VAC or VDC, making it compatible with a wide range of existing low-voltage control panels and power supplies.
Q: How many events can the AT4 store?
A: The AT4 supports 254 daily/weekly events, a total weekly event capacity of 1,778, and 254 programmable holiday dates.
Q: Does the AT4 have battery backup?
A: Yes. It supports a 12VDC sealed lead acid or gel battery for relay output backup, with up to 300mA charge current. A separate CR2032 lithium cell maintains the clock independently.
Q: What is the relay contact rating?
A: Each of the 4 Form C relay contacts is rated at 10A @ 120VAC or 28VDC — sufficient for most commercial door strikes, magnetic locks, and lighting contactors.
Q: What are the operating temperature limits?
A: The AT4 operates from -20°C to 49°C (-4°F to 120°F), suitable for unheated mechanical rooms and most North American indoor/sheltered environments.
Q: Can the AT4 handle holiday scheduling?
A: Yes. Up to 254 specific calendar dates can be programmed as holiday exceptions, eliminating manual reprogramming before scheduled closures or special events.
The AT4 is one of those workhorses I keep specifying on mid-size commercial retrofits precisely because the 12–24 VAC/VDC input flexibility means I can wire it into almost any existing cabinet without sourcing a new transformer. The 1,778 weekly event capacity and 254 holiday dates genuinely cover the most demanding multi-zone schedules I've encountered on school campuses and corporate campuses alike.
Technical Highlights:
- Form C Relay Contacts @ 10A: Four independently programmable outputs each rated 10A at 120VAC/28VDC — you can drive door strikes, magnetic locks, and lighting relays directly without intermediate hardware on most commercial loads.
- Dual Battery Architecture: Main SLA/gel battery sustains relay outputs during outages (300mA max charge); a separate CR2032 keeps the clock running even if the main battery is pulled — useful during service calls where you need to swap the backup battery without losing the schedule.
- -20°C to 49°C Range: Handles unheated IDF closets and mechanical rooms in northern climates without a heater kit, which simplifies the enclosure BOM on budget-conscious installs.
Deployment Considerations:
- Size the SLA battery to your expected outage duration — the AT4's 300mA charge ceiling means a large 12Ah battery will take several hours to fully recharge after a deep discharge, so don't underestimate runtime needs on critical circuits.
- The enclosure is 12" x 7.5" x 4.5" — verify cabinet depth before ordering, particularly in shallow surface-mount enclosures where 4.5" depth is a tight fit.
The AT4 is the right call for school districts, corporate campuses, or healthcare facilities that need annual holiday-aware scheduling across four independent relay circuits without deploying a full building automation controller. If your site only needs a single output on a 7-day schedule, a simpler timer will do — but the moment holiday exceptions and multiple independent outputs enter the picture, the AT4 earns its place.
