Honeywell 2MLI-D28A 64-Point Digital Input Module

Product Overview

The Honeywell 2MLI-D28A is a high-density 64-point digital input module built for the MasterLogic-200 (ML200) PLC system. Supporting both sink and source-type DC 24 V inputs, this module delivers exceptional I/O density for large-scale automation projects. With photo-coupler isolation, individual LED status indicators, and a wide operating temperature range, the 2MLI-D28A is engineered for demanding applications in production line control, safety interlocks, and facility monitoring.

Key Features

• 64 high-density digital input channels — maximum I/O density per module
• Sink/Source configurable DC 24 V inputs
• Configurable response time: 1 ms to 100 ms (default 3 ms)
• Photo-coupler isolation — AC 560 V rms / 3 cycles
• Individual LED indicators for all 64 channels
• Dual 40-pin connectors for organized high-density wiring
• Wide temperature range: −20°C to +60°C
• Ultra-compact — 150 g

Technical Specifications

• Model: 2MLI-D28A
• Product Type: Digital Input Module
• Series: MasterLogic-200
• Input Channels: 64 points
• Input Type: Sink / Source (DC 24 V)
• Rated Input Voltage: DC 24 V
• Input Voltage Range: DC 20.4 V – 28.8 V (ripple < 5%)
• Rated Input Current: Approx. 4 mA
• Input Resistance: Approx. 5.6 kΩ
• On Voltage / Current: ≥ DC 19 V / ≥ 3 mA
• Off Voltage / Current: ≤ DC 11 V / ≤ 1.7 mA
• Response Time: Configurable 1–100 ms; default 3 ms
• Isolation Method: Photo-coupler
• Isolation Voltage: AC 560 V rms / 3 cycles
• Isolation Resistance: ≥ 10 MΩ
• Common Grouping: 32 points per COM (2 COM groups)
• Current Consumption: Approx. 60 mA
• Status Indicators: LED for each input channel
• External Connection: 40-pin connectors × 2
• Weight: 0.15 kg
• Operating Temperature: −20°C to +60°C
• Storage Temperature: −40°C to +85°C
• Humidity: 5% to 95% RH (non-condensing)
• Certifications: CE

Typical Applications

• Large-scale production line monitoring and control
• Safety interlock systems and emergency stop circuits
• Facility-wide status monitoring and alarm inputs
• Conveyor and material handling system control
• High-density packaging and assembly automation

FAQ

Q: How many inputs does the 2MLI-D28A provide?
A: It provides 64 digital input points — the highest density in the MasterLogic-200 digital input lineup.

Q: How are the commons organized?
A: The 64 points are grouped into two commons of 32 points each, allowing flexible wiring for different sensor groups.

Q: What connectors are used for field wiring?
A: The module uses two 40-pin connectors. Pre-assembled breakout cables to terminal blocks are recommended for clean cabinet wiring.

Q: Can I mix sink and source sensors on the same module?
A: Yes. Each 32-point COM group can be wired independently as sink or source, provided the external power connections are configured correctly.

Q: Is the module suitable for outdoor or cold environments?
A: With an operating range of −20°C to +60°C, it handles colder environments than standard 0–55°C modules. For extreme cold, verify additional enclosure heating.

Installation Guide

1. Power Isolation: Ensure the MasterLogic-200 rack is completely powered down before installing or removing the module.
2. Slot Placement: Insert the 2MLI-D28A into any available I/O slot. Press firmly until the module locks into the backplane connector.
3. Connector Attachment: Connect the two 40-pin connectors to the module front. Label cables clearly (e.g., "COM1 — Inputs 0–31" and "COM2 — Inputs 32–63").
4. Field Wiring: Use breakout cables to route signals to terminal blocks. For each 32-point group, wire the COM terminal according to your sensor type (sink = 0 V, source = +24 V).
5. Response Time Configuration: In SoftMaster, set the input filter per channel or globally. Use 1 ms for high-speed applications and 10–100 ms for mechanical switch debouncing.
6. LED Verification: Power on and activate each input. Verify that the corresponding LED illuminates and the PLC I/O table reflects the correct state.

Selection Tips

• Choose the 2MLI-D28A when you need maximum digital input density (64 points) in a single module slot.
• For smaller I/O counts or simpler wiring, the 2MLI-D22A (16-point) or 2MLI-D24A (32-point) may be more cost-effective.
• Plan cable management carefully — 64 wires require organized routing. Use cable ducts and labeled breakout boards.
• Verify that your power supply capacity accounts for the ~60 mA module draw plus all connected sensor loads.
• When mixing NPN and PNP sensors, clearly segregate wiring by COM group to avoid configuration errors.