Allen-Bradley 1756-OB16DK Output Module 16-Point

Allen-Bradley 1756-OB16DK Diagnostic DC Output Module for ControlLogix Systems

Product Introduction

The Allen-Bradley 1756-OB16DK is a diagnostic DC output module for ControlLogix platforms. This module belongs to the ControlLogix series. It provides 16 diagnostic outputs with 8 points per group. Each output sources 24V DC power to field devices.

What makes the 1756-OB16DK special is its diagnostic capability. The module detects open wires, short circuits, and field power loss. This feedback helps you identify failures quickly. Consequently, machine downtime decreases significantly.

Technical Specifications

Output Characteristics
The 1756-OB16DK operates on 24 Volts DC source voltage. Operating voltage range spans from 19.2 to 30 Volts DC. Maximum output current per point reaches 2 Amps. Module current rating is 8 Amps at 30°C. At 60°C, the rating drops to 4 Amps.

Pilot duty current measures 2 Amps at 30°C. At 60°C, pilot duty current is 1 Amp. Output delay times are fast. Off-to-on nominal delay is 60 microseconds. Maximum off-to-on delay reaches 1 millisecond. On-to-off nominal delay is 630 microseconds. Maximum on-to-off delay reaches 5 milliseconds.

Power Requirements
Backplane current at 5 Volts draws 250 milliamps. Backplane current at 24 Volts draws 140 milliamps. Total backplane power draw equals 4.4 Watts. Maximum power dissipation is 3.3 Watts at 60°C. Thermal dissipation measures 11.25 BTU per hour.

Isolation and Protection
Isolation voltage rating is 50 Volts continuous. The module features conformal coating. This coating protects against corrosive elements in hazardous locations.

Environmental and Mechanical Data

Temperature Ratings
Operating temperature must not exceed 60°C around the module. Storage temperature ranges from -40°C to 85°C. The enclosure is open type. North American temperature code T4A is compliant.

Vibration and Shock
Vibration rating reaches 2 G at 10 to 500 Hertz. Operating shock rating is 30 G. These ratings ensure reliable operation in industrial environments.

Removable Terminal Blocks
The 1756-OB16DK works with specific terminal blocks. Compatible options include:

• 1756-TBCH

• 1756-TBS6H

Installation Guidelines

First, ensure the chassis power is off. Install the 1756-OB16DK into any available ControlLogix chassis slot. The module requires only one slot. Next, connect the removable terminal block. Use 1756-TBCH or 1756-TBS6H for wiring.

Furthermore, connect field devices to the source outputs. Each output provides 24V DC. Wire gauge should match current requirements. Do not exceed 2 Amps per point. Finally, configure diagnostic parameters in your Studio 5000 project. Enable open wire and short circuit detection.

Diagnostic Features Explained

The 1756-OB16DK monitors each output channel individually. It detects three fault conditions. First, open wire condition indicates broken field wiring. Second, short circuit condition shows excessive current. Third, field power loss warns about missing supply voltage.

Additionally, the module reports status back to the controller. Your program can react to these faults instantly. This reduces troubleshooting time significantly.

Packaging List

• 1 x Allen-Bradley ControlLogix diagnostic output module (1756-OB16DK)

• 1 x Conformal coated unit with factory labels

• 1 x Anti-static protective bag

• 1 x Factory cardboard box

Note: Removable terminal block is sold separately.

Shipping Information

All orders ship via FedEx, UPS, or DHL. Delivery typically takes 3 to 7 business days.

Frequently Asked Questions (FAQ)

1. What diagnostics does the 1756-OB16DK provide?
The 1756-OB16DK detects open wires, short circuits, and field power loss. Each output channel reports status individually to the controller.

2. Can I use this module without diagnostic features?
Yes, you can disable diagnostic monitoring in software. The module then functions as a standard DC output module. However, you lose the fault detection benefits.

3. What terminal blocks work with the 1756-OB16DK?
Use 1756-TBCH or 1756-TBS6H removable terminal blocks. Standard ControlLogix terminal blocks like 1756-TBNH are not compatible.

4. Is the 1756-OB16DK suitable for hazardous locations?
Yes, the conformal coating provides protection against corrosive elements. The module complies with T4A North American temperature code for hazardous locations.

5. What happens when an output short circuit occurs?
The 1756-OB16DK detects the short circuit immediately. It reports the fault to the controller. The module also protects itself by limiting current. Replace the field wiring after clearing the fault.