Overview
The Allen-Bradley 1794-ASB Series C is a Remote I/O communication adapter module from the Flex I/O product family, designed for distributed I/O architecture in industrial automation systems. This 1794-ASB adapter features a single Remote I/O (RIO) interface for connecting Flex I/O racks to RIO-capable controllers and includes an integrated 24VDC-to-5VDC power supply that energizes up to eight I/O modules simultaneously. Series C includes firmware enhancements over earlier revisions.
Key Features
- DIN rail mounted with one Remote I/O (RIO) communication port
- Supports three communication rates: 57.6Kbps, 115.2Kbps, and 230.4kbps
- Accommodates up to eight Flex I/O modules for distributed I/O expansion
- Built-in status indicators: Power LED, Adapter Active LED, Adapter Fault LED, and Local Fault LED
- Includes diagnostic indicators, remote I/O wiring connections, address/group switch assemblies, and reset pushbutton
- Integrated power supply converts 24VDC to 5VDC for backplane operation
Technical Specifications
- Input voltage range: 11–31.2 VDC (nominal 24VDC), 5% AC ripple maximum
- Maximum power consumption: 450 mA at 24VDC
- Power dissipation: 4.6 Watts at 31.2VDC; thermal dissipation 15.7 BTU/hour
- Dimensions: approximately 4 × 2 × 4 inches
- Weight: 6 ounces
- Enclosure type: Open design with IP 20 ingress protection; requires protective cabinet enclosure
- Communication baud rates: 57.6 Kbps, 115.2 Kbps, 230.4 Kbps
Typical Applications
- Distributed control systems in manufacturing plants; remote monitoring and control in industrial automation setups
- Multi-module Flex I/O system expansion where centralized controller connection is impractical
- Legacy PLC and SLC500 system retrofits requiring Remote I/O architecture
- Analog signal acquisition and control via Flex I/O analog input/output modules
Compatibility & Replacements
Compatible With
- Allen-Bradley legacy controllers: PLC2, PLC3, PLC5
- SLC500 automation platform
- Modern Logix controller platforms
- Third-party devices supporting Remote I/O protocol
- Belden 9463 or equivalent Remote I/O network cables
Replaces / Drop-In Replacement For
- Allen-Bradley 1794-ASB Series A, B (with firmware considerations)
- Earlier 1794-ASB revisions in legacy systems (verify processor compatibility before replacement)
- Direct replacement only within Series C/D configurations; consult integrator for cross-series swaps
Works With
- Block Transfer Read (BTR) and Block Transfer Write (BTW) ladder instructions
- Flex I/O analog input modules (1794-IE8, 1794-OE8, etc.)
- Flex I/O digital I/O modules
- Legacy RIO protocol via Belden 9463 network cable
- CE-certified for European Union compliance
