Allen-Bradley - 1756-A4 ControlLogix Chassis

Allen-Bradley 1756-A4 ControlLogix Chassis

Quick Specifications Overview

• Total Slots: 4 module slots including processor and I/O
• Chassis Dimensions: 263 x 169 x 145 mm (10.35" x 6.65" x 5.71")
• Backplane Power: 15A @ 5.1V DC total capacity
• Power Dissipation: 4 Watts maximum
• Mounting: Horizontal panel mounting only
• Weight: 0.75 kg (1.7 lb) lightweight design
• Enclosure: Open-style for cabinet installation

Chassis Configuration Details

• Slot Capacity: Four total slots for module installation
• Power Supply Location: Separate dedicated mounting area
• Module Compatibility: All ControlLogix processors and I/O modules
• Empty Slot Requirement: 1756-N2 filler modules mandatory
• Mounting Method: Secure panel mounting with provided hardware

Power Distribution System

• 5.1V DC Backplane: 15A chassis total / 6A per slot maximum
• 24V DC Backplane: 2.8A chassis total / 2.8A per slot maximum
• 3.3V DC Backplane: 4A chassis total / 4A per slot maximum
• 1.2V DC Backplane: 1.5A chassis total / 1.5A per slot maximum
• Efficiency: Low 4W power dissipation for cool operation

Physical Dimensions & Space Planning

• Chassis Footprint: 263mm width x 169mm height x 145mm depth
• Minimum Cabinet Size: 507 x 507 x 203 mm (20" x 20" x 8")
• Weight Characteristics: Lightweight 0.75kg for easy handling
• Panel Clearance: Adequate space for wiring and maintenance
• Compact Design: Ideal for space-constrained installations

Compatible Power Supplies

• Standard Models: 1756-PA72, 1756-PB72
• Enhanced Models: 1756-PA75, 1756-PB75, 1756-PC75
• Specialized Models: 1756-PH75 for specific applications
• Selection Guidance: Choose based on module power requirements
• Installation Note: Power supply mounts separately from main slots

Advanced System Features

• RIUP Capability: Safe Removal and Insertion Under Power
• Electronic Keying: Prevents incorrect module installation
• High-Speed Backplane: Optimized module-to-module communication
• Hot Swap Support: Module replacement without system shutdown
• Diagnostic Monitoring: System status and health indicators

Installation Requirements

• Mounting Orientation: Horizontal mounting mandatory
• Cabinet Requirements: Standard industrial enclosure
• Ventilation Needs: Adequate air circulation around chassis
• Wiring Access: Front-accessible terminal blocks
• Safety Compliance: Follow all local electrical codes

Application Scenarios

• Compact Control Systems: Small machine automation
• Distributed I/O Applications: Remote I/O drops
• System Expansion: Additional I/O capacity
• Standalone Applications: Dedicated process control
• Mobile Equipment: Space-constrained installations

Frequently Asked Questions

What are the main advantages of the 4-slot chassis?

• The 1756-A4 provides compact size with full ControlLogix performance, perfect for applications where space is limited but reliability is critical.

How many modules can I install in this chassis?

• You can install up to four ControlLogix modules, including processors, I/O, communication, and specialty modules in any combination.

What power supplies are compatible?

• The chassis works with 1756-PA72, PB72, PA75, PB75, PC75, and PH75 power supplies, chosen based on your module power requirements.

Can this chassis be used in distributed systems?

• Yes, the 1756-A4 is ideal for distributed I/O applications when equipped with a communication adapter module.

What are the RIUP capabilities?

• Removal and Insertion Under Power allows safe module replacement while the system remains operational, minimizing downtime.

How much cabinet space is required?

• Plan for minimum 20" W x 20" H x 8" D cabinet space to accommodate the chassis and provide proper maintenance access.

What about empty slots?

• All unused slots must be filled with 1756-N2 slot filler modules for safety and proper air flow.

For technical specifications and application assistance, contact our automation experts at: sales@nex-auto.com