Product Overview
When your control system needs dependable remote I/O communication, the Allen-Bradley 1794-ASB2 Remote I/O Adapter delivers consistent performance in demanding industrial environments. Part of the Flex I/O 1794 family, this adapter supports up to two Flex I/O modules, making it an ideal choice for compact distributed control architectures.
The 1794-ASB2 operates on a 24V DC power supply and offers selectable communication rates of 57.6 Kbps, 115.2 Kbps, and 230.4 Kbps. Its robust design includes red/green status indicators for power, adapter, and local connection states, simplifying diagnostics and reducing downtime.
Key Technical Specifications
Every parameter of the Allen-Bradley 1794-ASB2 is engineered for reliable remote I/O operation. The table below outlines the critical specifications:
| Specification |
Value |
| Manufacturer |
Allen Bradley |
| Category |
PLCs |
| Product Line |
Flex I/O 1794 |
| Part Number |
1794-ASB2 |
| UPC |
612598170890 |
| Weight |
0.44 lbs (0.20 kg) |
| Voltage |
24V DC |
| I/O Capacity |
2 Modules |
The adapter requires a 24V DC supply with an inrush surge current of 23 A for 2 ms per connected adapter. Its current load is 175 mA at 24V DC, with maximum current draws of 450 mA and 330 mA at 24V DC. Power consumption is 4.2 W at 24V DC, while maximum power dissipation is 3.4 W at 19.2V DC. Thermal dissipation measures 11.6 BTU/hr at 19.2V DC.
Input voltage range spans 19.2–31.2V DC (including 5% AC ripple), and the nominal input voltage is 24V DC. The FlexBus output provides a maximum current of 640 mA at 5V DC. Isolation is basic type with a continuous 50V rating; type-tested from power-to-system, power-to-RIO, and RIO-to-system at 750V DC for 60 seconds.
Industry Applications
The Allen-Bradley 1794-ASB2 excels in applications requiring compact remote I/O expansion. Common use cases include:
- Material handling systems where distributed I/O reduces wiring costs.
- Process control skids needing flexible I/O placement.
- Packaging machinery that demands fast, reliable communication.
With communication rates up to 230.4 Kbps, the adapter supports real-time data exchange, ensuring responsive control in high-speed automation lines.
Installation & Setup Guidance
Mount the 1794-ASB2 on a DIN rail or panel using its open enclosure. Verify the power supply meets the inrush surge requirement to avoid voltage drops. Set the communication rate via the adapter’s DIP switches (not included) according to your network configuration. Ensure proper grounding and follow the isolation ratings to maintain system integrity.
Maintenance & Reliability
Routine inspection of the adapter’s status indicators helps identify power or communication faults early. Keep the enclosure clean and within the IP20 rating environment to prevent dust ingress. The device’s thermal dissipation of 11.6 BTU/hr at 19.2V DC ensures stable operation under continuous load. Periodic checks of wiring connections and power supply voltage within the 19.2–31.2V DC range will extend service life.
Compatibility & Integration
The Allen-Bradley 1794-ASB2 is designed for Flex I/O systems and supports remote I/O communication via the RIO protocol. It is not compatible with classic PLC-5/15 and PLC-5/25 processors; using it with those processors may cause damage. Integrate with Allen-Bradley PLCs that support remote I/O scanning for seamless operation.
Buying Guide
When purchasing the 1794-ASB2, confirm your power supply can deliver the required inrush current and that your controller supports remote I/O. Consider ordering spare modules to minimize downtime. PLC Source PRO offers genuine Allen-Bradley parts with fast shipping and competitive pricing, ensuring your automation projects stay on schedule.