Allen-Bradley 1756-OB32K – ControlLogix DC Output Module with 32-Point Outputs

The Allen-Bradley 1756-OB32K is a ControlLogix DC output module. Specifically, this module provides 32-point source outputs. It operates at 12-24 Volts DC with a source output configuration. Furthermore, this module features a conformally coated circuit board (indicated by the K suffix). Consequently, it suits demanding industrial applications requiring high-density DC output control.

Ordering Configuration and Product Identification

• Manufacturer: Rockwell Automation.

• Brand: Allen-Bradley.

• Part Number: 1756-OB32K.

• Series: ControlLogix.

• Module Type: DC Output Module.

• Number of Outputs: 32-point total.

• Output Type: Source (sourcing) configuration.

• Voltage Rating: 12-24 Volts DC.

• Operating Voltage Range: 10-31.2 Volts DC.

• Enclosure: None (open-style module).

• Conformal Coating: Yes (K suffix indicates coating).

• Therefore, the Allen-Bradley 1756-OB32K offers high-density sourcing outputs for DC loads.

Output Current Ratings

• Maximum Current per Point (at 50°C): 0.5 Amps.

• Maximum Current per Point (at 60°C): 0.35 Amps.

• Maximum Current per Module (at 50°C): 16 Amps total.

• Maximum Current per Module (at 60°C): 10 Amps total.

• Derating Required: Yes, as temperature increases.

• Application: Solenoids, relays, indicator lights, and small actuators.

• Load Type: Resistive or inductive with proper suppression.

• Thus, the 1756-OB32K requires temperature derating for reliable operation.

Power Dissipation and Backplane Current

• Power Dissipation (Max at 60°C): 4.8 Watts.

• Backplane Current (5 Volts): 300 milliamps.

• Thermal Dissipation: Approximately 16.4 BTU per hour.

• Isolation Voltage (Continuous): 50 Volts.

• Power Consumption: Moderate for 32-point module.

• Chassis Loading: Account for backplane current in system design.

• Consequently, the Allen-Bradley 1756-OB32K consumes reasonable backplane power.

Removable Terminal Blocks

• Compatible Terminal Block 1: 1756-TBCH.

• Compatible Terminal Block 2: 1756-TBS6H.

• Terminal Block Type: Removable (plug-in design).

• Wiring Benefit: Easy module replacement without rewiring.

• Installation Speed: Faster than fixed terminal blocks.

• Field Wiring: Accepts standard copper conductors.

• Screw Torque: Follow standard ControlLogix specifications.

• Maintenance: Simple disconnect and reconnect.

• Therefore, the 1756-OB32K simplifies installation and maintenance.

Conformal Coating (K Suffix)

• Coating Type: Conformal coating on circuit board.

• Purpose: Protects against moisture, dust, and chemicals.

• Suffix Meaning: K indicates conformally coated version.

• Application: Harsh or corrosive environments.

• Benefit: Extended product lifespan in demanding conditions.

• Comparison: Standard version (without coating) for clean environments.

• Industries: Chemical processing, marine, outdoor installations.

• Humidity Resistance: Improved protection against condensation.

• Thus, the Allen-Bradley 1756-OB32K suits harsh industrial environments.

Output Configuration and Features

• Output Type: Source (sourcing) configuration.

• Number of Groups: Typically 2 groups of 16 points.

• Common Configuration: Points share common per group.

• Output Status Indicators: LEDs for each channel.

• Fault Detection: Open wire and short circuit detection.

• Electronic Protection: Current limiting and thermal shutdown.

• Load Compatibility: 12V or 24V DC devices.

• Field Power: External 10-31.2V DC supply required.

• Application Flexibility: Mixed voltage devices on different groups.

• Consequently, the 1756-OB32K provides robust output protection.

Installation Guide

First, verify that all system power sources are completely disconnected. Then, select an available slot in your ControlLogix chassis. The 1756-OB32K can be placed in any I/O slot. After that, slide the module into the chosen slot. Push firmly until the backplane connector is fully seated. Next, select your removable terminal block (1756-TBCH or 1756-TBS6H). Attach the terminal block to the module front. Then, wire your field devices to the terminal block terminals. Connect the external DC power supply (10-31.2V DC) to the common terminals. Ensure proper polarity for source outputs. For 50°C ambient, limit each point to 0.5A and total module to 16A. For 60°C ambient, reduce to 0.35A per point and 10A total module. Then, apply backplane power by turning on the ControlLogix system. Download your output configuration to the module. Finally, test each output point using your control program. As a result, the Allen-Bradley 1756-OB32K will provide reliable DC output control.

Packaging List

• One Allen-Bradley 1756-OB32K DC output module

• One removable terminal block (1756-TBCH or 1756-TBS6H, order separately)

• One product identification label

• One installation and wiring guide

• Conformal coating (pre-applied to circuit board)

Common FAQs

Q1: How many outputs does the Allen-Bradley 1756-OB32K provide?
A: This module provides 32-point source outputs. Specifically, it operates at 12-24 Volts DC. Therefore, it suits high-density DC load control applications.

Q2: What is the maximum current per point on the 1756-OB32K?
A: At 50°C, the maximum current is 0.5 Amps per point. However, at 60°C, it derates to 0.35 Amps per point. Therefore, ambient temperature affects output capacity.

Q3: What terminal blocks are compatible with the Allen-Bradley 1756-OB32K?
A: This module accepts 1756-TBCH or 1756-TBS6H removable terminal blocks. Both options provide easy wiring and maintenance. Consequently, module replacement does not require rewiring.

Q4: What does the K suffix mean on the 1756-OB32K?
A: The K suffix indicates conformal coating on the circuit board. Therefore, this version provides enhanced protection against moisture, dust, and chemicals. It suits harsh or corrosive environments.

Q5: What is the backplane current draw of the Allen-Bradley 1756-OB32K?
A: This module draws 300 milliamps at 5 Volts DC from the backplane. Power dissipation is 4.8 Watts maximum at 60°C. Therefore, account for these values in your chassis loading calculations.