Allen-Bradley 1771-ID Isolated AC/DC Discrete Input Module, 6 Inputs, 120V AC/DC

Allen-Bradley 1771-ID Isolated 120V AC/DC Input Module for PLC-5 Systems

The Allen-Bradley 1771-ID is a PLC-5 compatible isolated AC/DC discrete input module designed to monitor field-level ON/OFF devices at 120V AC or DC. It installs into a single slot of a 1771 I/O chassis and provides six individually isolated input channels for improved noise immunity and signal integrity.

Individually Isolated Discrete Input Architecture

• Six isolated AC/DC input channels
• Supports 92–138V AC or DC input signals
• Opto-electrical isolation between channels
• Front-panel LED indicators for input status

Reliable Signal Conditioning and Backplane Integration

The module incorporates input filtering to reduce false triggering caused by electrical noise or contact bounce. Each channel processes field signals independently before transferring logic states to the PLC-5 backplane for deterministic control performance.

Industrial Control Applications

• Monitoring limit switches and pushbuttons
• Discrete input sensing for selector and float switches
• Isolated multi-phase industrial control circuits