1746-OW8 | Allen-Bradley | SLC 500 Digital Relay Contact Output Module

Product Overview

The Allen-Bradley 1746-OW8 serves as a versatile electromechanical interface for the SLC 500 controller platform. This digital contact output module provides eight Normally Open (N.O.) relay channels, allowing the PLC to control high-voltage AC or DC field devices. It acts as a bridge between low-level logic and high-power equipment such as motor starters, solenoids, and heavy-duty indicators. We supply this unit as 100% Brand New and Original, ensuring optimal mechanical life and electrical integrity for your automation system.

Technical Specifications

Engineering Advantages

• Universal Voltage Compatibility: The 1746-OW8 switches a broad range of voltages, from 5V to 265V AC and 5V to 125V DC. This flexibility allows engineers to mix AC and DC loads within the same controller rack, provided they follow the group isolation rules.

• Dual-Group Isolation: The module organizes its eight outputs into two isolated groups of four. This configuration enables the control of two different voltage sources simultaneously, significantly reducing the need for additional interposing relays in the cabinet.

• Robust Load Handling: Each relay point supports up to 1.5 Amps at 120V AC. The electromechanical contacts handle high inrush currents better than solid-state alternatives, making the 1746-OW8 the preferred choice for driving inductive loads like magnetic contactors.

• Simplified Troubleshooting: On-board status LEDs provide immediate visual confirmation of each output state. Maintenance personnel can verify logic execution at the module faceplate without opening the PLC programming software.

FAQs

• Q: Can the 1746-OW8 switch both AC and DC loads on the same module?

  A: Yes. Since the module features two isolated groups (4 points per common), you can apply AC power to one common and DC power to the other. However, you must ensure that all four points within a single group share the same power source and return path.

• Q: Does this module require an external power supply for the relay coils?

  A: No. The 1746-OW8 draws the necessary power to energize its internal relay coils directly from the SLC 500 backplane (approx. 85-90 mA at 5V DC). You only need to provide external power for the field-side loads connected through the contacts.

• Q: How do the response times of the 1746-OW8 compare to transistor modules?

  A: Mechanical relays are naturally slower than solid-state outputs. The 1746-OW8 has a maximum signal delay of 10 ms for both "On" and "Off" transitions. For high-speed applications like precision pulse-width modulation (PWM), use a transistor module like the 1746-OB16.

• Q: What mounting precautions should I take for this relay module?

  A: Install the module in any slot of the SLC 1746 chassis except Slot 0. To maximize contact life when switching inductive loads, we recommend installing external surge suppressors (RC networks for AC, diodes for DC) across the load to prevent arcing and electrical noise.