Overview
The Allen-Bradley 1746-A2 is a fixed I/O expansion chassis designed for the SLC 500 programmable controller series. This 2-slot expansion rack provides the flexibility to add additional I/O and communication modules to existing SLC 500 systems without requiring a complete system redesign. The 1746-A2 supports back-panel mounting and integrates seamlessly via interconnect cabling, allowing consolidation of I/O and expansion of system capacity in industrial control applications.
Key Features
- 2-slot module capacity for additional I/O, communication, or specialty modules
- Back-panel mounting for straightforward integration into existing control panels
- Requires dedicated power supply (5.1 VDC and 24 VDC backplane)
- Supports up to 3 chassis interconnection for maximum 30 total module slots
- Compact dimensions (5.5″ × 7″ × 4″) for space-constrained enclosures
- Modular design for simple installation and configuration
Technical Specifications
The Allen-Bradley 1746-A2 provides the following specifications:
- Backplane Voltage (5V Rail): 10 A maximum at 5.1 VDC
- Backplane Voltage (24V Rail): 2.88 A maximum at 24 VDC
- Module Slots: 2 slots for I/O and specialty modules
- Dimensions: 5.5″ × 7″ × 4″
- Weight: Approximately 0.3 kg (0.66 lbs)
- Mounting Style: Back-panel/DIN rail compatible
- Enclosure Type: Open frame
Typical Applications
The 1746-A2 expansion rack is ideal for:
- Expanding I/O capacity on existing SLC 500 control systems
- Adding discrete input/output modules to fixed-I/O systems
- Integrating communication modules (ASCII, network adapters) without processor replacement
- Consolidating multiple standalone controllers into one modular system
- Industrial manufacturing, packaging, and process control environments
- Field upgrades where physical space in control enclosures is limited
Compatibility & Replacements
Compatible With
- SLC 500 processors (1747-L series and equivalent)
- SLC 500 I/O modules (1746-IO series discrete and analog cards)
- SLC 500 communication modules (1746-ASB, 1746-NET, etc.)
- SLC 500 specialty modules (thermocouple, high-speed counter, motion)
- Allen-Bradley interconnect cabling (1746-C series)
- RSLogix 500 programming software
Replaces / Drop-In Replacement For
The 1746-A2 is a fixed-slot configuration suitable for system expansions. Verify specific module compatibility with your system integrator or controller configuration before ordering.
Works With
- RSLogix 500 and Studio 5000 (with legacy SLC 500 support)
- Allen-Bradley SLC 500 network protocols (EtherNet/IP adapters)
- 1746-A2 supports interconnection with up to 2 additional chassis for expanded capacity
- Modular I/O addressing and configuration within processor memory
