Allen-Bradley 1756-OX8I ControlLogix Isolated Relay Output Module

Product Overview

The Allen-Bradley 1756-OX8I module delivers eight isolated relay outputs for the ControlLogix platform. Each channel offers both Normally Open (N.O.) and Normally Closed (N.C.) contacts. This design allows you to mix AC and DC loads on the same module. The 1756-OX8I is ideal for motor starters, contactors, pilot lights, and annunciator panels.

Technical Specifications

The 1756-OX8I supports a wide operating voltage range. For AC circuits, the range goes from 10 to 265 Volts AC. For DC circuits, the range goes from 5 to 150 Volts DC. Each relay is a Form C contact output. The module provides true channel-to-channel isolation.

Key electrical parameters include:

• Output Current Rating: 2 A, 0.5 A, or 0.25 A depending on voltage.

• Initial Contact Resistance: 100 mΩ at 6V and 1 A.

• Maximum Switching Frequency: One operation every 3 seconds (0.3 Hz at rated load).

• Mean Bounce Time: 1.2 milliseconds.

• Maximum Output Delay Time: 13 milliseconds.

Performance and Contact Life

The 1756-OX8I offers predictable long-term reliability. Its expected contact life reaches 300,000 operations for resistive loads. For inductive loads, the life reaches 100,000 operations. These ratings help you plan maintenance schedules properly. The module draws 100 mA from the 5V backplane. Maximum power dissipation sits at 3.1 Watts at 60°C.

Isolation and Environmental Data

This module provides strong electrical separation. Isolation voltage reaches 250V continuous between outputs and backplane. The basic insulation type also covers output-to-output isolation. The 1756-OX8I operates from 0 to 60 °C (32 to 140 °F). Storage temperature ranges from -40 to 85 °C (-40 to 185 °F). It handles 5 to 95% non-condensing humidity without issues.

Installation Guidelines

Install the 1756-OX8I into any 1756 chassis slot. Follow these steps for a correct setup.

1. Disconnect Power: Always remove chassis power before insertion.

2. Align the Module: Slide the 1756-OX8I into the chosen slot.

3. Lock the Tabs: Push the top and bottom locking mechanisms firmly.

4. Attach the RTB: Use compatible 1756-TBCH or 1756-TBS6H terminal blocks.

5. Wire the Loads: Connect each relay output to its load individually.

You can wire the 1756-OX8I as a non-isolated module. Simply short the L1 connections on the RTB. Use the 1756-JMPR or a third-party jumper wire for this purpose.

Package Contents

Your box will contain the following standard items.

• One 1756-OX8I ControlLogix isolated relay module

• One module label sheet for identification

• One set of keying pins for slot positioning

Note: The removable terminal block (RTB) is sold separately. This package includes no certificates or warranty documents. The weight applies to the module only.

Common FAQs

1. Can I wire AC and DC loads on the same 1756-OX8I?
Yes, each relay is individually isolated. You can mix AC and DC outputs freely.

2. What RTBs work with the 1756-OX8I?
Use the 1756-TBCH or 1756-TBS6H removable terminal blocks for this module.

3. Why does my output switch slowly at high currents?
The maximum switching frequency is 0.3 Hz at rated load. Reduce your switching speed.

4. How do I know if a relay contact has failed?
Monitor the expected contact life of 300 kHz resistive load. Replace the 1756-OX8I after this limit.

5. Does this module support hot swapping?
Yes, the 1756-OX8I supports insertion under power. This reduces system downtime significantly.

Ordering and Logistics

We stock the genuine Allen-Bradley 1756-OX8I for immediate shipment. The current price is ¥6,250.00 RMB. The product gross weight is 0.42 kg. We ship using FedEx, UPS, and DHL for fast global delivery. Contact our team for bulk discounts and availability.