Allen‑Bradley 1746‑IB16 SLC 500 Digital Input Module

1746‑IB16 is a standard discrete DC input module for Rockwell Allen‑Bradley SLC 500 PLC series. It provides 16‑channel sinking NPN‑type digital signal acquisition, receiving 10‑30VDC field signals from proximity sensors, limit switches, push‑buttons and relay auxiliary contacts, and transmits digital status data to SLC CPU through rack backplane for automatic logic processing.

This single‑slot compact module adopts optical isolation and EMI filtering to resist industrial electromagnetic interference. Each channel is fitted with independent LED indicator for real‑time signal diagnosis. It installs directly into 1746 series rack, supports hot‑swap operation, and delivers stable 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 1746 I/O System
• Channel Configuration: 16 sinking DC input points, common terminal for all channels
• Rated Input Voltage: 24VDC, operating voltage range 10‑30VDC
• Electrical Parameter: Nominal input current 8mA @24VDC, maximum off‑state leakage current 1mA
• Response Delay: Max 8ms ON delay, max 8ms OFF delay
• Isolation: 500VDC optical isolation between field circuit and PLC backplane bus
• Backplane Power Consumption: 0.05A @5VDC
• Installation: Single slot for 1746 rack, removable terminal block, cabinet IP20 protection
• Operating Environment: -20℃ ~ +60℃, 5%‑95% RH non‑condensing, anti‑vibration industrial grade
• Diagnostic: Independent LED status indicator for each input channel
• Certifications: CE, UL, meets global factory automation standards

Core Functions

• Collect sinking DC discrete signals from field NPN sensors, limit switches, emergency stop buttons and relay feedback contacts.
• Optical isolation isolates noisy field circuits from PLC internal logic to prevent interference damage to main CPU hardware.
• Front‑panel LED lights show real‑time channel status, helping technicians quickly locate open‑circuit and sensor faults on site.
• Deliver 16‑point digital status data to SLC 5/01‑5/05 CPUs via rack backplane for cyclic logic execution.
• Built‑in hardware filter suppresses voltage spike and contact bounce to avoid false triggering of PLC control programs.
• Hot‑swap single‑slot structure supports module replacement without shutting down whole PLC rack to reduce equipment downtime.

Application Scenarios

• Digital input spare replacement for SLC 500 PLC cabinets in automobile assembly lines, packaging machinery and textile workshops.
• Field signal acquisition module for water‑treatment plants, sewage pumping stations and heating furnace auxiliary automation systems.
• Maintenance spare inventory for petrochemical interlock detection, mining conveyor safety monitoring and power distribution control cabinets.
• Matching input expansion module used with SLC CPU, relay output modules and analog acquisition boards.
• Retrofit replacement for old automation systems with signal loss, unstable detection and damaged terminals.
• Global aftermarket spare parts for automation maintenance teams maintaining Rockwell SLC 500 control equipment.