Allen‑Bradley 1746‑IB16 SLC 500 16‑Channel Sinking DC Digital Input Module

1746‑IB16 is a standard discrete DC input module designed exclusively for Rockwell Allen‑Bradley SLC 500 PLC series. It provides 16‑channel sinking (NPN) digital signal acquisition, receiving 10–30VDC field signals from proximity sensors, limit switches, pushbuttons and relay contacts, and transmitting digital status data to the SLC CPU via the rack backplane for automated logic judgment.

This compact single‑slot module features built‑in optical isolation and EMI filtering to resist industrial electromagnetic interference. Each channel is equipped with independent LED status indicators for real‑time signal diagnosis. It adopts plug‑in rack mounting without extra DIN rails, supports hot‑swap replacement, and delivers stable long‑term signal collection for assembly lines, water treatment and power auxiliary control systems.

Main Specifications

• Brand: Allen‑Bradley (Rockwell Automation); Model: 1746‑IB16; Series: SLC 500 PLC 1746 I/O Rack
• Channel Configuration: 16 sinking DC input points, all channels share one common terminal
• Operating Voltage Range: 10VDC to 30VDC, rated working voltage 24VDC
• Electrical Parameters: Nominal input current 8mA @24VDC; max off‑state leakage current 1mA
• Signal Delay: Max 8ms for ON state, max 8ms for OFF state switching response
• Isolation Grade: 500VDC optical isolation between field circuits and PLC backplane bus
• Backplane Power Draw: 0.05A @5VDC, no 24VDC backplane power consumption
• Physical Installation: Single slot for 1746 series rack, removable terminal block, IP20 cabinet protection
• Operating Environment: -20℃ ~ +60℃ working temperature, 5%–95% RH non‑condensing, anti‑vibration industrial grade
• Diagnostic Design: Individual LED indicator for each input channel to display signal on/off status
• Certifications: CE, UL industrial certification, compliant with global factory automation standards

Core Functions

• Capture discrete sinking DC signals from field NPN sensors, mechanical limit switches, emergency stop buttons and auxiliary contact feedbacks.
• Optical isolation separates field high‑noise circuits from PLC internal logic circuits to eliminate cross‑interference and protect the main CPU.
• Front‑panel LED lights show real‑time channel status, enabling field technicians to quickly locate open circuits or faulty sensors without programming tools.
• Transmit all 16‑point digital status data to SLC 5/01~5/05 CPUs through the rack backplane for automatic cycle logic execution.
• Built‑in hardware filtering suppresses transient voltage spikes and contact bounce signals to avoid false trigger of PLC control programs.
• Hot‑swappable single‑slot structure allows independent module replacement without shutting down the entire PLC rack to reduce production downtime.

Application Scenarios

• Digital input spare replacement for SLC 500 PLC control cabinets in automobile assembly lines, packaging machinery and textile production workshops.
• Field signal acquisition module for water treatment plants, sewage pumping stations and heating furnace auxiliary automation control systems.
• Maintenance backup inventory for petrochemical compressor interlock detection, mining conveyor safety monitoring and new energy power distribution control cabinets.
• Matching input expansion module paired with SLC series CPU, relay output modules and analog signal acquisition boards.
• Retrofit replacement for aging automation systems suffering signal loss, unstable detection and damaged channel terminals.

• Global aftermarket spare supply for factory automation maintenance teams managing Rockwell SLC 500 control equipment worldwide.