Overview
The Allen-Bradley 1794-ASB Series E Flex Remote I/O Adaptor is a communication module designed to interface FLEX I/O distributed I/O racks with PLC/SLC and ControlLogix systems via Remote I/O (RIO) protocol. This adapter functions as both a communication gateway and power supply, converting 24 VDC input to 5 VDC for the FLEX I/O backplane. The Series E variant represents a mature, field-proven design widely used in legacy control systems and retrofit applications requiring distributed I/O expansion.
Key Features
- 8-Module Capacity: Communicates with up to 8 FLEX I/O modules
- Multiple Baud Rates: Communication rates of 57.6 Kbps, 115.2 Kbps, and 230.4 Kbps
- DIN Rail Mounting: DIN rail mounted device with one Remote I/O communication port
- Flexible Addressing: Supports standard, compact, complementary, standard-32, and complementary-32 addressing modes
- Built-in Diagnostics: Three indicator lights for active adapter, local fault, and adapter fault status
- Hot-Swappable Design: Modules can be inserted or removed while the system is running
Technical Specifications
- Input Voltage (Nominal): 24 Volts DC nominal, operating range 19.2 to 31.2 Volts DC with 5% AC ripple
- FlexBus Output: 5VDC at 640 mA maximum with 500 Volts AC isolation voltage
- I/O Module Capacity: 8 modules
- Power Consumption: 330 mA
- Communication Protocol: Remote I/O (RIO), legacy protocol
- Cable Specification: Recommended Belden 9463 or equivalent cables
- Dimensions: Approximately 4 x 2 x 4 inches
- Weight: 6 ounces (160 gm)
- Operating Temperature: -20°C to +55°C
- Series: Series E (supersedes A, B, C, D variants)
Typical Applications
The 1794-ASB remote I/O adapter/power supply is a Flex I/O module that communicates between connected SLC or PLC racks across an RIO Link. Common applications include:
- Distributed I/O expansion for SLC500 and PLC5 systems
- Remote machine control with centralized monitoring
- Multi-zone production line integration
- Facility automation and building management systems
- Legacy system upgrades requiring FLEX I/O compatibility
Compatibility & Replacements
Compatible With
- PLC2, PLC3, and PLC5 controllers
- SLC500 automation platforms
- PLC, SLC, and ControlLogix models
- FLEX I/O digital and analog I/O modules
- RIO scanner ports on supported controllers
- Supports block transfer instructions (BTW/BTR) for analog modules
Replaces / Drop-In Replacement For
- Allen-Bradley 1794-ASB Series A, B, C, D variants (backward compatible)
- Earlier-generation Remote I/O adapter modules in FLEX I/O product family
Works With
- Remote I/O (RIO) protocol communication network
- Allen-Bradley FLEX I/O module family
- Block Transfer Read (BTR) and Block Transfer Write (BTW) instructions
- Studio 5000 Logix Designer (legacy project support)
- RSLogix 5 programming environment
