2MLI-A21A Honeywell I/O Module AC100-240V DC24V Photo Coupler Isolation

2MLI-A21A Honeywell MasterLogic-200 I/O Module | 8/16 Point Input

The Honeywell 2MLI-A21A is a digital input module for the MasterLogic-200 PLC family. It carries two input groups in one unit. The AC group handles 8 points at 100 to 240 V. The DC group handles 16 points at 24 V. Both groups use photo coupler isolation. This design blocks field noise from the logic side. As a result, the module suits mixed-voltage panels in process and factory lines.

AC Input Group Data

• Input points: 8 point
• Isolation method: Photo coupler isolation
• Rated input voltage: AC100 to 240 V (+10 / -15 %)
• Frequency: 50 / 60 Hz, ±3 Hz
• Distortion rate: 5 %
• Rated input current: about 17 mA at AC200 V, 60 Hz
• Rated input current: about 14 mA at AC200 V, 50 Hz
• Inrush current: max 500 mA for under 1 ms at AC264 V
• Input derating: Yes
• On voltage: AC80 V or higher
• On current: 5 mA or higher at 50 / 60 Hz

DC Input Group Data

• Input points: 16 point
• Isolation method: Photo coupler isolation
• Rated input voltage: DC24 V
• Operation range: DC20.4 to 28.8 V, ripple under 5 %
• Input derating: None
• On voltage: DC19 V or higher
• On current: 3 mA or higher
• Off voltage: DC11 V or lower
• Off current: 1.7 mA or lower
• Weight: 0.13 kg

Electrical Behavior Notes

• AC inputs draw higher current at 60 Hz than at 50 Hz
• Inrush stays under 500 mA for 1 ms at AC264 V
• AC side needs derating in hot cabinets
• DC side runs without derating across its range
• Photo coupler isolation separates each group from logic

Suitable Equipment and Systems

• Honeywell MasterLogic-200 PLC racks
• Process panels with mixed AC and DC signals
• Legacy Honeywell control systems needing spares
• Factory lines with 24 V sensor banks
• Panels with 100 to 240 V pushbutton and relay contacts
• Retrofit projects keeping existing MasterLogic wiring