Allen‑Bradley 1746-IB16 16‑Point 24VDC Sinking Digital Input Module for SLC 500 PLC System

Product Description

1746-IB16 is a standard discrete DC input module for Rockwell SLC 500 modular PLC racks, designed to collect 24VDC field switch, proximity sensor, limit switch and relay contact signals. It adopts current sinking (sink) input circuit, all 16 points share one common COM terminal, with built-in hardware signal filtering to suppress contact bounce and industrial EMI interference.

Each channel matches an independent green status LED to quickly judge on-site signal status. Equipped with detachable screw terminal block, no need to remove the whole module during wiring maintenance. It directly inserts into SLC500 backplane and takes power from the rack backplane, widely used as replacement spare for old production line SLC PLC control cabinets.

Technical Specifications

PN: 1746-IB16, Manufacturer: Allen‑Bradley (Rockwell Automation, USA)

Compatible System: Full SLC 500 series CPU (1747-L511/L524/L531/L542 etc.)

Input Type: DC sinking input

Total Channels: 16 digital input points, 1 common group (16 points per COM)

Operating Voltage Range: 10–30VDC (nominal 24VDC)

Nominal Input Current: 8mA per channel @24VDC

Off-state Max Leakage Current: ≤1mA

Signal Delay: Max 8ms ON / 8ms OFF hardware filter

Backplane Power Draw: 5VDC bus 0.05A, no 24VDC external rack power consumption

Isolation: 500VDC isolation between field signal and PLC backplane circuit

Termination: Removable blue screw terminal block

Indicator: 16 independent green channel status LEDs

Mount: Single slot SLC500 rack plug-in

Operating Temp: 0℃ ~ +60℃; Storage: -40℃ ~ +85℃

Humidity: 5%–95% non‑condensing, IP20 cabinet grade

Weight: ~0.4kg

Configuration Software: RSLogix 500, RSLogix Micro

Key Features

16 high-density DC input points, reduces rack slot occupation for multi-signal acquisition.

Sinking input circuit, matches most NPN proximity sensors and mechanical switches on site.

Built-in 8ms hardware filter, effectively eliminate contact jitter and transient electrical interference.

Independent LED per channel, rapid on-site troubleshooting without PLC software monitoring.

Detachable terminal block, wiring modification or module replacement without re‑crimping cables.

500VDC isolation between field side and control backplane, avoid field surge damaging PLC CPU.

Low backplane power consumption, suitable for multi-module expansion SLC rack layout.

Fully compatible all SLC500 CPU models, plug-and-play without extra program configuration.

Application Scope

Production line conveyor, packaging machine limit switch & proximity signal acquisition

Water treatment, sewage plant flow switch, level switch discrete signal input cabinet

Thermal power auxiliary equipment, boiler auxiliary valve feedback signal collection module

Metallurgy, cement, printing machinery old SLC500 PLC control cabinet spare replacement

Oil & gas small station auxiliary safety switch, interlock status signal input board

Global aging SLC500 automation system overhaul, spare inventory and equipment retrofit