1746-OB32E DC Output Module | Allen-Bradley SLC 500

1746-OB32E Digital DC Output Module

Product Introduction

The Allen-Bradley 1746-OB32E is a high-density digital DC output module designed for the SLC 500 programmable controller family. This module delivers 32 discrete output channels, each electronically protected against overload and short-circuit conditions. It operates within a 10-30 Volts DC range and is ideal for applications requiring numerous output points in a compact form factor. Furthermore, the 1746-OB32E integrates seamlessly into both fixed and modular SLC 500 hardware configurations, offering flexibility for system designers.

Key Technical Specifications

The Allen-Bradley 1746-OB32E provides substantial output capacity and advanced protection features. First, this module contains 32 outputs arranged in two groups, with each group having 16 points sharing a common connection. Each output supports either 0.5 amps or 0.25 amps, depending on the specific configuration and load requirements. The total continuous current for the entire module is 4 amps, while the total module current capacity reaches 8 amps. Additionally, the backplane current consumption at 5 Volts DC is only 190 milliamps, and it draws 0 mA at 24V DC, which places a minimal burden on the system power supply.

Specifically, the nominal output voltage is 24V DC, with a wide operating range of 10-30 Volts DC, ensuring compatibility with various industrial power sources. The signal delay times are remarkably fast, with an ON delay of just 0.1 ms and an OFF delay of 1.0 ms, enabling precise control in high-speed automation sequences. Meanwhile, the step response measures 60 milliseconds for the input side and 2.5 milliseconds for the output side, providing balanced performance for most control scenarios.

Electronic Protection Features

A standout feature of the 1746-OB32E is its integral electronic protection, which distinguishes it from the standard 1746-OB32 model. This built-in protection actively safeguards against short circuits and overload current conditions through a thermal cut-out mechanism. When the module detects a fault, the affected channel automatically limits the current output within milliseconds after reaching the set thermal threshold. Importantly, other channels not experiencing fault conditions continue to function normally, as each channel has individual detection capability.

However, it is crucial to understand certain limitations of this protection system. First, the 1746-OB32E does not include reverse polarity protection or protection against improper signal source wiring errors. Additionally, the electronic protection is not equivalent to an external electronic fuse. Therefore, proper external protection devices are still recommended for installation alongside this module. Furthermore, the module auto-resets when an overload condition is cleared, which has significant operational implications. After the thermal cut-out resets, the module implements the previous command state. If the command was ON, the module will turn the connected load back on after error recovery. This behavior may be either safe or unsafe depending on your specific application, so you must carefully evaluate this recovery condition during system design.

Mechanical and Environmental Limits

The 1746-OB32E is built to endure challenging industrial environments with robust mechanical specifications. For instance, the operating temperature ranges from -13 to 140 degrees Fahrenheit, while the non-operating temperature spans from -40 to 185 degrees Fahrenheit. It also functions reliably in relative humidity conditions of 5-95% non-condensing. Moreover, the module withstands operating vibration of 2g at 10-500 Hz and operating shock of 30g, with additional vibration tolerance of 2.5g at 57-2000 Hz. The terminal block features a self-lifting lift plate that accepts two 14 AWG (2 mm²) cables, simplifying field wiring connections.

Status Indication and Installation Guidelines

Front-panel LED indicators provide clear visual status for each output point. Specifically, these indicators illuminate when the correct signal is applied to the input terminal or when the processor outputs are energized. This feature simplifies troubleshooting and system monitoring. For installation, route input power to the 1746-OB32E using a separate path from the cables connected to I/O devices, which helps minimize electrical noise interference. The module uses color-coded removable terminal blocks that simplify wiring and future maintenance tasks.

Packaging List

• Allen-Bradley 1746-OB32E Digital DC Output Module (1 unit)

• Color-coded Removable Terminal Block (RTB)

• Installation instruction sheet

Shipping Information

All orders are shipped via FedEx, UPS, or DHL to ensure fast and reliable delivery worldwide. Tracking information will be provided upon shipment.

Frequently Asked Questions (FAQ)

Q1: What is the difference between the 1746-OB32 and the 1746-OB32E?
The 1746-OB32E includes integral electronic protection against overloads and short circuits, while the standard 1746-OB32 does not offer this built-in protection. The protection feature uses a thermal cut-out mechanism that limits current on affected channels.

Q2: Does the 1746-OB32E include reverse polarity protection?
No, this module does not include reverse polarity protection or protection against improper signal source wiring errors. You should implement appropriate external protection measures during installation.

Q3: What happens after an overload condition clears on the 1746-OB32E?
The module auto-resets and implements the previous command state. If the command was ON, the module will turn the connected load back on after error recovery, which may have safety implications depending on your application.

Q4: Can the 1746-OB32E drive both AC and DC loads?
No, this module is specifically designed for DC loads only. It operates within a 10-30 Volts DC range and is not compatible with AC voltage applications.

Q5: How many outputs does the 1746-OB32E have and how are they arranged?
The module provides 32 outputs arranged in two groups, with each group containing 16 points sharing a common connection. Each output supports 0.5 amps or 0.25 amps depending on configuration.