Johnson ACM-48A & AEM-48A Fire Alarm Display Card: Complete Technical & Installation Guide

General Description & System Architecture

The Johnson ACM-48A is an advanced Annunciator Control Module featuring 48 color-programmable active LEDs. It is engineered to deliver immediate visual feedback concerning active alarm conditions, system faults, and operational statuses across complex building networks.

To scale monitoring capability, the Johnson AEM-48A serves as a dedicated expander module, seamlessly doubling the capacity of the ACM-48A to support a total of 96 distinct monitoring points. Together, this modular pairing ensures robust, centralized status tracking for high-demand life-safety architectures.

Technical Specifications of ACM-48A & AEM-48A

Review the electrical, physical, and environmental parameters of the Johnson ACM-48A and Johnson AEM-48A modules to verify compatibility with your fire alarm control panel (FACP) loop:

• Power Supply Requirements: 24V DC nominal (operates within a range of 17V DC to 28V DC)

• Current Draw Profile:

• On-line flashing state (all auxiliary LEDs off): 0.016 A

• Active alarm condition (all LEDs fully illuminated): 0.070 A

• Physical Dimensions:

• ACM-48A: 8.375 in. (213 mm) high $\times$ 4.375 in. (111 mm) wide

• AEM-48A: Identical physical footprint to the ACM-48A

• Operating Temperature: 0°C to 49°C (32°F to 120°F)

• Environmental Humidity: Up to 93% relative humidity ($\pm$2%) at 32°C ($\pm$2°C)

Advanced Functional Features

1. Tri-Color Programmable LEDs: Each of the 48 active indicator lights can be individually configured to display red, green, or yellow, providing precise visual categorization of system events.

2. Dedicated Fault & Power Diagnostics: Built-in system fault and primary power indicators ensure maintenance staff can instantly diagnose internal panel health.

3. Integrated Piezo Sounder: An on-board acoustic alarm generator emits audible signals during unacknowledged alarm states, boosting situational awareness for operators.

4. Silence & Acknowledge Controls: A physical switch allows technicians or security personnel to mute the local piezo sounder and acknowledge active events directly at the module level.

5. Plug-and-Play Expansion: The Johnson AEM-48A connects via a dedicated ribbon interface to the ACM-48A, scaling system capacity without complex reconfiguration.

Target Applications in Critical Infrastructure

The Johnson ACM-48A and Johnson AEM-48A configuration is widely specified across multiple high-stakes sectors:

• Commercial Office Complexes & Retail Towers: Delivering rapid zone identification across multi-story real estate.

• Industrial Manufacturing Plants & Warehouses: Providing rugged monitoring nodes capable of withstanding heavy operational environments.

• Educational Campuses: Enhancing safety protocols throughout school networks and university administration buildings.

• Healthcare Facilities & Hospitals: Supporting critical-care environments where immediate, unambiguous emergency response is essential.

Professional Installation & Wiring Guidelines

Execute the following steps to ensure safe mechanical mounting and reliable data communication:

1. Site Preparation: Ensure the installation environment is clean, dry, and free of structural obstructions. Keep insulated screwdrivers and precision wire strippers on hand.

2. Mechanical Mounting: Secure the Johnson ACM-48A into its designated fire-rated wall enclosure or backbox using appropriate hardware, maintaining adequate spacing around the chassis for thermal ventilation.

3. Power & Expansion Wiring: Terminate the 24V DC supply lines directly to the labeled power inputs. For capacity expansion, bridge the Johnson AEM-48A to the main board using the factory-supplied ribbon cable into the matching socket.

4. Configuration & Addressing: Adjust internal DIP switches according to your panel layout specifications, and clearly apply custom designation labels next to each LED bank.

5. Functional Testing: Power up the loop, simulate alarm and fault triggers to verify LED response matrices, and confirm that the local piezo sounder activates as intended.

Related Part Numbers & Series Alternatives

For system scaling or alternative point requirements within this product family, consider these matched components:

• Johnson ACM-24AT: 24-point control module with integrated graphic display options.

• Johnson AEM-24AT: 24-point expander module designed for smaller-scale zone scaling.

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