Overview
The Allen-Bradley 1746-OV8 is a digital discrete output module engineered for SLC 500 modular automation systems. This single-slot module delivers eight (8) current-sinking output channels operating across a 10–50V DC range, with nominal 24V DC operation. Its optical isolation, filtered signal circuitry, and robust construction make it ideal for industrial control applications requiring reliable on/off switching of loads in clean, dry environments.
The 1746-OV8 is a field-proven legacy module widely used in process control, machine automation, and discrete manufacturing systems. With removable terminal blocks and front-panel LED indicators, it supports straightforward troubleshooting and wiring flexibility.
Key Features
- 8 Current-Sinking Output Channels: Single group of 8 points with per-point common capability
- Operating Voltage Range: 10–50V DC (nominal 24V DC)
- Low Power Consumption: 135 mA backplane current at 5V DC; 0 mA at 24V DC
- Optical Isolation & Filtering: Built-in noise reduction and signal protection
- Removable Terminal Blocks: Color-coded for fast wiring and maintenance access
- LED Output Status Indicators: Front-panel LEDs for real-time I/O diagnostics
- Compact Single-Slot Form Factor: Direct installation into any SLC 500 chassis
Technical Specifications
- Output Voltage Range: 10–50V DC
- Number of Outputs: 8 points (1 common group)
- Output Type: Current sinking (transistor)
- Continuous Current per Point (30°C): 1.0 A
- Continuous Current per Point (60°C): 0.5 A
- Continuous Current per Module (30°C): 8.0 A
- Continuous Current per Module (60°C): 4.0 A
- Maximum On-State Voltage Drop: 1.2V @ 1.0A
- Maximum Off-State Leakage: 1 mA
- On-Signal Delay: 0.1 ms maximum
- Off-Signal Delay: 1.0 ms maximum
- Backplane Current Consumption (5V DC): 135 mA
- Backplane Current Consumption (24V DC): 0 mA
- External Power Draw (24V DC): 0.8 A maximum
- Thermal Dissipation: 6.9 W maximum per module
- Operating Temperature: 0–60°C
- Operating Shock: 30 g
- Terminal Block Wire Capacity: Two 14 AWG (2 mm²) wires per terminal
- Mounting: Single-slot SLC 500 module rack
- Certifications: UL listed, cUL listed, CE marked
Typical Applications
The 1746-OV8 is used across industrial and manufacturing environments where discrete DC output switching is required:
- Machine Automation: Motor starters, solenoid valve control, pneumatic actuators
- Process Control: Alarm signaling, fan/pump enable/disable, pilot light control
- Material Handling: Conveyor and sorting system logic
- Production Equipment: Assembly line control, palletizers, robotic interfaces
- Building Automation: HVAC damper control, lighting logic
Compatibility & Replacements
The 1746-OV8 /A installs directly into any SLC 500 modular chassis (e.g., 1746-A2, 1746-A4 racks) alongside compatible processors (SLC 5/01 through 5/05). It is not compatible with fixed-I/O SLC 500 systems or CompactLogix/MicroLogix processors, which use different form factors.
When upgrading legacy systems, engineers often specify the 1746-OVP16 (16-point fused variant) or 1746-OB8 (sourcing output option) as functional alternatives. For modern ControlLogix platforms, equivalent functionality is available via 1756-OB16 or 1769-OB16 modules.
The /A revision designation indicates Series A construction. Verify processor compatibility and system configuration through the SLC 500 Modular Hardware Style User Manual (publication 1747-UM011).
