Allen-Bradley 1756-OV32E 32-Point DC Output Module

1756-OV32E ControlLogix Electronically Fused Output Module Overview

The Allen-Bradley 1756-OV32E provides 32 sinking DC outputs with individual electronic fusing. This high-density module belongs to the ControlLogix platform and offers excellent protection for each output channel. The electronic fusing detects overcurrent conditions and automatically shuts down the affected point, preventing damage to the module and connected field devices. Furthermore, the module reports fault status directly to the controller, enabling quick diagnostics and reducing maintenance time.

Technical Specifications and Performance

This output module accepts a supply voltage from 10V to 30V DC, with a nominal rating of 24V DC. The 1756-OV32E delivers a maximum output current of 0.5A per point at 50 °C, derating to 0.35A per point at 60 °C. For the entire module, the aggregate current reaches 16A at 50 °C and 10A at 60 °C. Each point also supports a surge current of 2A for 10ms, recurring every 2 seconds, which handles the inrush from inductive loads effectively.

Signal response times are fast and predictable. The OFF-to-ON transition has a maximum delay of 300μs, while the ON-to-OFF transition completes within 1ms maximum. Additionally, each output signal synchronizes with the Coordinated System Time (CST) every 16.7 seconds, ensuring coordinated operation across multiple modules in the chassis.

The 1756-OV32E draws 390 mA from the 5.1V backplane and 2 mA from the 24V supply, resulting in a total backplane power of 2.04 W. Its maximum power dissipation reaches 5.88 W at 60 °C, equivalent to 20.1 BTU/hr of thermal energy. The off-state leakage current stays below 1mA per point, preventing false activation of sensitive loads. Furthermore, the voltage drop across each output in the ON state is only 350 mV at 0.5A, maintaining efficient power delivery.

Mechanical and Environmental Specifications

The 1756-OV32E operates reliably across a temperature range of 0 to 60 °C (32 to 140 °F). It tolerates relative humidity from 5% to 95% without condensation, suitable for various industrial environments. The module carries both IEC and North America T4 temperature codes, confirming its safety for hazardous locations. Its open enclosure design requires installation inside a proper control cabinet. The isolation voltage stands at 250V with basic insulation type, routinely tested at 1350V AC for 2 seconds.

Installation Guidelines

Installing the 1756-OV32E follows the standard ControlLogix procedure. First, power down the chassis completely before handling any modules. Insert the module into an available slot and push firmly until the locking tab engages securely. Then, attach a compatible removable terminal block – choose either the 1756-TBCH (36-position screw-type) or the 1756-TBS6H (36-position spring-clamp type). Wire your DC loads to the appropriate output terminals, observing correct polarity for sinking outputs. The common terminal connects to the positive side of the DC supply, while each load connects between its output terminal and the negative side. After completing all wiring, restore power to the chassis. Finally, configure the module in the controller's I/O tree and test each output point to verify proper operation. The electronic fusing activates automatically and provides fault feedback through status LEDs and controller tags.

Packaging List

Your shipment for the 1756-OV32E includes:

• One Allen-Bradley 1756-OV32E ControlLogix Output Module

• One removable terminal block (1756-TBCH or 1756-TBS6H, subject to availability)

• One quick-reference guide with terminal assignments

• Anti-static protective packaging

Frequently Asked Questions (FAQ)

1. What is the difference between the 1756-OV32E and the 1756-OV16E?
The 1756-OV32E offers 32 output points with 0.5A per point, while the 1756-OV16E provides 16 outputs at 1A per point. Choose the OV32E for high-density, lower-current applications and the OV16E for fewer outputs with higher current capacity.

2. Which terminal block does the 1756-OV32E require?
This module uses either the 1756-TBCH (36-position screw-type) or 1756-TBS6H (36-position spring-clamp) removable terminal blocks. These differ from the 20-pin blocks used on 16-point modules.

3. Can I use this module with 5V DC loads?
No, the 1756-OV32E requires a supply voltage between 10V and 30V DC. Using it with 5V loads will not provide reliable operation, as the minimum load current is 2mA and the voltage drop may exceed the load tolerance.

4. How does the electronic fusing recover after a fault?
Once the overcurrent condition clears, the electronic fuse resets automatically when the output command turns off and then on again. You can also reset it through your control program or by cycling the module power.

5. What is the total current I can draw from all 32 outputs?
The aggregate current for the 1756-OV32E is 16A at 50 °C and 10A at 60 °C. Even though individual points handle 0.5A each, you must monitor the total current to prevent overheating and ensure reliable operation.