Allen-Bradley 1756-OA8E ControlLogix AC Output Module

1756-OA8E Product Introduction

The Allen-Bradley 1756-OA8E is a high-performance output module from Rockwell Automation's renowned ControlLogix product family. It provides eight discrete AC output points, each featuring electronic fusing for superior circuit protection. This module handles nominal 120V AC loads, with a flexible operating range of 74 to 132V AC. Consequently, it is well-suited for controlling various field devices like solenoids, motor starters, and indicator lamps.

Furthermore, the 1756-OA8E is designed with two isolated groups of four outputs each. This configuration enhances its flexibility and safety in complex control schemes. Its integrated electronic fusing protects each channel individually, minimizing downtime by preventing a single fault from affecting other outputs. Ultimately, this ControlLogix module delivers the reliability and intelligence needed for critical automation tasks.

1756-OA8E Technical Specifications

The Allen-Bradley 1756-OA8E boasts robust technical parameters. Its output voltage range spans from 74 to 132V AC at a frequency of 47-63 Hz. Meanwhile, the maximum output current is rated at 2 Amps per point at 60°C. For the entire module, the total output current is 8 Amps at 30°C, derating linearly to 4 Amps at 60°C.

Besides its power ratings, the 1756-OA8E exhibits efficient switching performance. Specifically, the output signal delay is only 9.3 ms at 60 Hz and 11 ms at 50 Hz for both ON-to-OFF and OFF-to-ON transitions. The module also features a maximum OFF-state leakage current of 3 mA per point. Additionally, each output can withstand a current surge of 20 Amps for 43 ms, recurring every 2 seconds.

1756-OA8E Power and Backplane Requirements

For integration, the 1756-OA8E draws 200 mA from the 5.1V DC backplane and 250 mA from the 24V DC backplane. Its total backplane power consumption is rated at 7.02 Watts. Consequently, the module dissipates a maximum of 5.5 Watts of power at 60°C, which translates to a thermal dissipation of 18.76 BTU/hr. These figures are crucial for calculating the overall heat load within your ControlLogix chassis.

Mechanical and Environmental Specifications

The 1756-OA8E operates reliably across a wide range of environmental conditions. Specifically, its operational temperature range is from 0°C to 60°C. It also functions in relative humidity of 5% to 95% (non-condensing). For storage and shipping, it can withstand temperatures from -40°C to 85°C.

In terms of isolation, the 1756-OA8E provides 125V of continuous isolation (basic insulation type) between outputs and the backplane and between output groups. This isolation is tested at 1200V AC for 2 seconds, ensuring high noise immunity and safety. The module is an open-style enclosure and carries a T4 temperature code.

Installation and Compatibility

Installing the Allen-Bradley 1756-OA8E is straightforward. It fits into any available slot in a standard ControlLogix chassis. You can freely mix multiple instances of this module within the same chassis to scale your I/O count as needed.

For wiring, the 1756-OA8E requires a removable terminal block (RTB). It is compatible with both the 1756-TBNH (NEMA) and 1756-TBSH (Spring clamp) RTBs. Remember to use the correct RTB type for your specific application to ensure secure and reliable field wiring connections.

Packaging List

When you receive your Allen-Bradley 1756-OA8E, the package will include the following items:

• 1 x 1756-OA8E ControlLogix Output Module

• 1 x Installation Instructions Guide

Note: The Removable Terminal Block (RTB) is sold separately. Please select the 1756-TBNH or 1756-TBSH to complete your installation.

All orders are shipped with care via our standard carrier partners: FedEx, UPS, or DHL.

Frequently Asked Questions (FAQ)

1. What type of loads can the 1756-OA8E control?
The 1756-OA8E is designed for 120V AC loads. Therefore, it can effectively control solenoids, relays, pilot lights, and contactors.

2. What is the advantage of its electronic fusing?
Electronic fusing on the 1756-OA8E protects each output point individually. This prevents a short circuit on one channel from affecting other outputs on the module, thus improving overall system reliability.

3. Which terminal block does the 1756-OA8E require?
The 1756-OA8E requires a compatible Removable Terminal Block. Specifically, you can use the 1756-TBNH (NEMA style) or the 1756-TBSH (spring clamp style), both sold separately.

4. How much current can the 1756-OA8E deliver at high temperatures?
At an ambient temperature of 60°C, the 1756-OA8E delivers a maximum of 2 Amps per point and 4 Amps total per module. A linear derating curve applies above 30°C.

5. Can I install multiple 1756-OA8E modules in one chassis?
Yes, absolutely. There is no limit to the number of 1756-OA8E modules you can install. You can install them in any available slot within your ControlLogix chassis to expand your output capacity.