Overview
The Allen-Bradley 1794-OB16 /A is a FLEX I/O discrete output module designed for distributed I/O applications in industrial automation. This 16-point digital output module provides current-sourcing 24V DC outputs, making it suitable for controlling relays, solenoids, indicator lamps, and other 24V DC field devices. The module integrates seamlessly into FLEX I/O racks and supports legacy and modern Logix controllers.
Key Features
- 16 sourcing 24V DC outputs — each rated 0.5A, totaling 8A module capacity
- Low signal delay — 0.5 ms OFF-to-ON, 1.0 ms ON-to-OFF response time
- Compact form factor — 94 × 94 × 69 mm (3.7 × 3.7 × 2.7 in.), 78g
- 16 yellow status LEDs — field-side output indication for easy troubleshooting
- DIN rail mounting — compatible with multiple terminal base units
- Robust isolation — 50V continuous, tested at 850V DC between field and system
Technical Specifications
- Output Type: Digital current sourcing (16 channels)
- Output Voltage: 10–31.2V DC (nominal 24V DC)
- Output Current per Channel: 1 mA minimum, 500 mA maximum
- Total Module Current: 8.0A (16 × 0.5A)
- On-State Voltage Drop: 0.5V DC max
- Signal Delay: 0.5 ms (OFF→ON), 1.0 ms (ON→OFF)
- Off-State Leakage: 0.5 mA max per channel
- Surge Current Rating: 2.0A for 50 ms, repeatable every 2 seconds
- Isolation Voltage: 50V continuous; type-tested at 850V DC for 1 second
- Operating Temperature: 0–55°C (32–131°F)
- Storage Temperature: -40–85°C
- Dimensions: 94 × 94 × 69 mm
- Weight: 78 grams
- FlexBus Current: 80 mA @ 5V DC
- Power Dissipation: 5.3W @ 31.2V DC max
- Thermal Dissipation: 18.1 BTU/hr @ 31.2V DC
Typical Applications
- Manufacturing assembly lines and machine tool control
- Material handling and conveyor systems
- Process automation (chemical, pharmaceutical, food processing)
- Valve, pump, and motor control
- Building automation (lighting, HVAC, access control)
- Distributed I/O for ControlLogix, CompactLogix, PLC5, and SLC500 systems
Compatibility & Replacements
Compatible With
- FLEX I/O terminal bases: 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3K, 1794-TB3SK
- FlexLogix Controller and 1794-FLA (FLEX I/O Local I/O Extender)
- Logix controllers: ControlLogix, CompactLogix (as distributed I/O)
- Legacy controllers: PLC-5, SLC-500
- Up to 8 instances per FLEX I/O rack
Replaces / Drop-In Replacement For
- 1794-OB16 (earlier revision without /A suffix)
- 1794-OB16P (protected output variant with electronic channel fusing)
Works With
- FLEX I/O communication adapters (Ethernet, ControlNet, DeviceNet, PROFIBUS, EtherNet/IP)
- Studio 5000 Logix Designer (configuration and monitoring)
- RSLogix 5, RSLogix 500 (legacy support)
- DIN rail mounting systems
