Allen-Bradley 1746-N2 SLC 500 Modular Chassis Slot Filler Cover

Protective Function and Purpose

The 1746-N2 is a passive mechanical component designed for the Allen-Bradley SLC 500 controller platform. Its primary function is to occupy vacant I/O slots within a 1746 chassis, providing an essential physical barrier for the backplane. By sealing unused openings, the 1746-N2 prevents the ingress of dust, metallic debris, and other airborne contaminants that could cause electrical short circuits or hardware degradation. Furthermore, it ensures proper airflow management within the enclosure, maintaining the thermal integrity of adjacent active modules.

Technical Characteristics

• Manufacturer: Allen-Bradley / Rockwell Automation

• Product Line: SLC 500

• Model Number: 1746-N2

• Hardware Type: Modular Card Slot Filler

• Compatibility: Any standard 1746 I/O Chassis slot

• Construction: Industrial-grade polymer housing

• Mounting: Snap-in installation (Self-locking tabs)

• Backplane Interaction: Non-electrical (Passive)

• Operating Temperature: 0°C to 60°C (32°F to 140°F)

• Dimensions: Occupies one (1) standard module slot width

• Weight: 0.09 kg (0.19 lbs)

System Maintenance and Reliability

In industrial automation environments, leaving a PLC backplane exposed is a significant risk factor for system failure. The 1746-N2 acts as a "dummy" module, giving the chassis a finished, professional appearance while strictly serving a protective role. Unlike active I/O modules, the 1746-N2 consumes no backplane current and requires no software configuration. It is an industry best practice to install these filler covers in any system expansion slots reserved for future use to comply with environmental protection standards for open-style industrial equipment.

Frequently Asked Questions

Does the 1746-N2 consume any power from the SLC 500 power supply?No. The 1746-N2 is a non-electronic component. It does not have a bus connector and therefore has a zero-milliamp draw on both the 5V and 24V DC backplane circuits.

Is this part required for the PLC to run?While the PLC processor will execute logic without slot fillers, the 1746-N2 is highly recommended to prevent environmental damage to the backplane pins and to ensure the chassis meets safety and cleanliness standards.