Honeywell 2MLI-A12A Digital Input Module

The Honeywell 2MLI-A12A is a high-performance 12-channel digital input module designed for use in modular I/O systems. It is part of the Modular Local I/O (MLI) platform, which supports flexible configurations in modern industrial control environments. This module captures discrete signals from field devices such as pushbuttons, limit switches, relays, and sensor outputs, and provides reliable status feedback to distributed control systems (DCS) or programmable logic controllers (PLC).

With built-in diagnostics, robust electrical isolation, and fast input scanning, the 2MLI-A12A module offers dependable operation in mission-critical applications. The module interfaces easily with control systems such as Honeywell Experion PKS, Safety Manager, and other field-based automation platforms, enabling seamless communication and integration across complex industrial architectures.

Product Specifications

Product Applications

The 2MLI-A12A module is designed to gather binary signals from field instruments and devices in a wide range of industrial automation scenarios. Key application areas include:

• Power Plants – Monitoring circuit breakers, status switches, and control cabinet interlocks.

• Oil & Gas Facilities – Detecting digital statuses from pressure switches, limit contacts, and ESD buttons.

• Pharmaceutical Manufacturing – Input detection from batch control systems and cleanroom interlocks.

• Water Treatment Systems – Monitoring float switches, pump run status, valve open/close signals.

• Food & Beverage Industry – Capturing conveyor signals, machine safeties, and door locks.

• Chemical Processing Units – Handling critical digital alarms and trip signals in hazardous areas.

Product Advantages

• High Density: Accommodates 12 digital inputs within a compact module, optimizing cabinet space.

• Fast Response: Rapid signal recognition with minimal delay ensures real-time control accuracy.

• Robust Isolation: Prevents ground loops and protects control systems from voltage spikes.

• Built-in Diagnostics: Simplifies troubleshooting by identifying wiring issues and signal faults.

• Versatile Mounting: Compatible with DIN rail and backplane setups for installation flexibility.

• Industrial Durability: Designed to withstand harsh conditions including wide temperature ranges and vibration.

• Field Proven: Backed by Honeywell’s long-standing reputation in process automation.

• Compliance: Meets global safety and performance standards, including ATEX and SIL certifications.

• Visual Feedback: Per-channel LED indicators allow easy status verification during operation.

• Seamless Integration: Fully interoperable with Honeywell’s DCS and Safety System architectures.

Frequently Asked Questions (FAQ)

1. What type of signals does the 2MLI-A12A module accept?

   It accepts standard 24 VDC discrete signals from field devices like pushbuttons, limit switches, and relays.

2. How many digital inputs are provided by this module?

   The module supports 12 independent digital input channels.

3. Is there electrical isolation between the inputs and system bus?

   Yes, the inputs are galvanically isolated from the backplane at ≥1500 VDC.

4. What diagnostic features are included?

   The module supports short-circuit protection and open wire detection to help identify wiring issues quickly.

5. Can the module be mounted on a DIN rail?

   Yes, the 2MLI-A12A can be mounted on DIN rails or integrated into a modular backplane.

6. What voltage level is required to turn the input ON?

   The input registers as ON when the signal exceeds 15 VDC.

7. Does the module include status LEDs for each input?

   Yes, each input channel has an associated LED to indicate its current logic state.

8. Is it safe to use in hazardous areas?

   Yes, the module is certified for use in ATEX Zone 2 environments.

9. Can the module operate under extreme temperatures?

   It supports operation from -20°C to +60°C and storage down to -40°C.

10. Is this module suitable for safety-instrumented systems?

    Yes, it is SIL2-capable and can be used in functional safety applications.