Allen‑Bradley 1746‑N2 SLC 500 Chassis Slot Filler Module

1746‑N2 is an official slot filler accessory designed by Allen‑Bradley (Rockwell Automation) exclusively for the SLC 500 PLC chassis series including 1746‑A4, 1746‑A7 and other rack models. It fits into any vacant standard I/O slot to fully block open rack openings, acting as a protective cover for unused backplane connectors. This accessory is a mandatory matching component to maintain the original thermal airflow layout of SLC modular control systems.

This slot filler draws minimal 50mA backplane current at 5VDC and contains no signal processing circuits. It was officially discontinued by Rockwell on September 30, 2024 with no direct replacement model. It is widely stocked as maintenance spare parts for legacy SLC 500 automation cabinets deployed across manufacturing, water treatment and energy industries worldwide.

Main Specifications

• Brand: Allen‑Bradley, Rockwell Automation; Model: 1746‑N2; Series: SLC 500 Accessory
• Product Type: Single‑slot chassis slot filler cover, no I/O or control functions
• Backplane Power Consumption: 50mA @ 5VDC, no 24VDC load
• Operating Temperature: 0℃ ~ +60℃; Storage Temperature: -40℃ ~ +85℃
• Humidity Tolerance: 5%~95% non‑condensing relative humidity
• Mechanical Compatibility: All 1746 series modular chassis (1746‑A2/A4/A7/A10/A13)
• Physical Feature: Standard single‑slot form factor with detachable front protective flap
• Lifecycle Status: Discontinued since Sep 30, 2024, no official replacement part
• Certifications: CE, UL, CSA compliant, Class I Division 2 hazardous location approved
• Net Weight: Approx 0.09kg; Country of Origin: United States

Core Functions

• Seal empty rack slots to block dust, metal debris and moisture from contaminating exposed backplane gold connectors, preventing short circuit or communication failure.
• Restore the original designed air convection channel of PLC chassis, guarantee uniform heat dissipation of CPU, power supply and I/O modules to avoid overheating alarms.
• Improve cabinet electromagnetic shielding performance, reduce EMI leakage through open slots and minimize signal interference from nearby inverters and high‑voltage equipment.
• Standard plug‑in design identical to functional I/O modules for fast installation and removal without extra fixing tools during on‑site cabinet reconfiguration.
• Front blank cover keeps cabinet layout neat and consistent, complying with industrial automation cabinet safety and maintenance standard specifications.
• Low power consumption design avoids abnormal backplane bus load errors caused by empty slots, maintaining stable communication of the entire SLC rack system.

Application Scenarios

• Spare slot filler replacement for 1746‑A4 4‑slot and other SLC 500 PLC racks in packaging, conveyor and assembly automation cabinets.
• Maintenance backup stock for vintage SLC control systems in municipal water treatment, textile printing and food processing factories.
• Cabinet renovation matching accessory for metallurgical cooling pump auxiliary control racks and boiler auxiliary small PLC control cabinets.
• Retrofit supporting parts for old plastic injection, printing and material handling equipment equipped with Allen‑Bradley SLC 500 platforms.
• Hazardous workshop cabinet auxiliary accessory for chemical plant auxiliary signal collection racks with strict dustproof requirements.
• Global aftermarket spare inventory for automation maintenance workshops servicing discontinued Rockwell SLC 500 hardware series.