Overview
The Allen-Bradley 1794-ASB is a Flex I/O Remote I/O (RIO) communication adapter module designed for distributed I/O architectures in industrial automation systems. This adapter is a DIN rail mounted device featuring one Remote I/O (RIO) communication port used for connecting Flex I/O rack to RIO capable controllers. The module supports multiple addressing modes (standard, compact, and complementary) and integrates seamlessly into legacy and modern Allen-Bradley control systems.
Key Features
- Accommodates up to 8 I/O modules, enabling the expansion of I/O capacity as needed.
- Supports 57.6Kbps, 115.2Kbps, and 230.4kbps communication rate with an input voltage requirement of 19.2 – 31.2 VDC.
- Allows for various addressing modes, including standard, compact, complementary, standard-32, and complementary-32, making it highly versatile for different configurations.
- CE-certified for use in the European Union.
- Built-in status LEDs for real-time diagnostics and troubleshooting.
- Power conversion: 24V DC to 5V DC for backplane distribution.
Technical Specifications
- Nominal Input Voltage: 24 VDC
- Operating Voltage Range: 19.2–31.2 VDC
- Maximum I/O Module Capacity: 8 modules
- Communication Protocol: Remote I/O (RIO—legacy protocol)
- Communication Speeds: 57.6 Kbps, 115.2 Kbps, 230.4 Kbps
- Power Consumption: 330 mA at 24V DC
- Power Dissipation: 4.6 W maximum
- Thermal Dissipation: 15.7 BTU/hr maximum
- Operating Temperature: 0°C to 55°C (32°F to 131°F)
- Storage Temperature: −40°C to 85°C (−40°F to 185°F)
- Isolation Voltage: 500V AC
- Mounting: DIN rail
- Enclosure Rating: IP20 (open type—requires protective cabinet)
- Dimensions: Approximately 4 × 2 × 4 inches
Typical Applications
The 1794-ASB is ideal for distributed control systems in industrial environments, offering a reliable and compact solution. Common use cases include:
- Remote I/O node communication across RIO networks
- Modular machine control with localized I/O racks
- Sequential and relay control logic implementations
- Analog and digital signal acquisition from distributed sensors
- Legacy system upgrades and expansions to modern Logix platforms
Compatibility & Replacements
Compatible With
- Legacy Allen-Bradley controllers such as PLC2, PLC3 and PLC5 controllers as well as SLC500 automation platforms.
- Modern Logix controller platforms as well as with 3rd party devices and encompass partner modules.
- Remote I/O network architectures supporting RIO communication
- Flex I/O distributed I/O modules (all types)
Replaces / Drop-In Replacement For
- Earlier generation 1794-ASB Series A and Series C models (verify series revision compatibility before ordering)
- Other RIO adapters in legacy Flex I/O configurations
- Note: Use a 1794-ASB Series D or later module for safe state recognition with FLEX Integral analog modules. Series E meets this requirement.
Works With
- RSLogix 5, RSLogix 500, and RSLogix Emulate software platforms
- Remote I/O (RIO) scanning controllers and I/O ports
- Belden 9463 or equivalent RIO communication cables
- Block Transfer Read/Write (BTR/BTW) instructions for data exchange
- Custom addressing modes: standard, compact, complementary, standard-32, complementary-32
