Product Overview of the Allen-Bradley 1794-OB32P

The Allen-Bradley 1794-OB32P is a high-density Flex I/O output module. Specifically, it belongs to the trusted 1794 Flex I/O product family. This module provides thirty-two (32) discrete output channels for control applications. Therefore, it executes PLC output commands with excellent reliability. The 1794-OB32P uses a sourcing output circuit type. As a result, it works perfectly with 24V DC field devices. Furthermore, each channel has individual electronic protection against overloads.

Output Channel Configuration and Electrical Specifications

First, let us examine the channel organization. The 1794-OB32P divides its 32 channels into two groups. Channels 0 through 15 form the first group. Similarly, channels 16 through 31 form the second group. Each group has its own separate voltage source. Consequently, you gain flexibility in power distribution.

The nominal on-state voltage for the 1794-OB32P is 24V DC. The minimum on-state voltage is 10V DC. Furthermore, the maximum on-state voltage reaches 31.2V DC. Each channel delivers a maximum on-state current of 500mA. Therefore, the module handles a wide range of loads. These loads include pilot lamps, buzzers, relay coils, and solenoid devices.

Current Ratings and Power Management

The 1794-OB32P has a maximum output current of 14.0 Amperes per module. However, the distribution between groups is not equal. Channels 0 through 15 provide a total of 6 Amperes together. In contrast, channels 16 through 31 provide a total of 8 Amperes. Therefore, you must plan your load distribution carefully. The minimum on-state current per channel is 1.0 milliampere. Additionally, the maximum output surge current reaches 2 Amperes for 50 ms. This surge can repeat every 2 seconds as needed.

The 1794-OB32P exhibits an off-state leakage current of only 0.5mA. As a result, it minimizes unwanted power consumption. The on-state voltage drop is a low 0.5V DC maximum. Consequently, most power reaches your load devices effectively.

Switching Performance and Response Times

The 1794-OB32P offers fast switching performance. The output delay from OFF to ON state is 0.5 milliseconds. Similarly, the delay from ON to OFF state is 1.0 millisecond. Therefore, this module suits high-speed control applications. Furthermore, the module includes thirty-two yellow status indicators. These LEDs show the on-off state of each channel clearly. Thus, troubleshooting becomes quick and intuitive.

Compatibility and Physical Requirements

The 1794-OB32P requires a compatible terminal base unit. Specifically, it works only with 1794-TB32 and 1794-TB32S terminal bases. Therefore, verify your base unit before purchasing. The module mounts on a standard DIN rail. This mounting method simplifies installation and replacement. The enclosure type is open-style. Hence, you must install it inside a protective cabinet.

Environmental and Isolation Specifications

You can operate the 1794-OB32P between 0 to 55 °C (32 to 131 °F) . Its storage temperature range is -40 to 85 °C (-40 to 185 °F) . Furthermore, this module withstands vibration of 5g at 10 to 500 Hz. It also tolerates an operating shock of 30g. The 1794-OB32P offers continuous isolation voltage of 50V between field side and system. Consequently, it provides adequate protection for most industrial environments.

The Flexbus current draw is 80mA at 5V DC. Maximum power dissipation reaches 5.3W at 31.2V DC. Similarly, maximum thermal dissipation is 18.1 BTU/hr at 31.2V DC. Therefore, ensure proper ventilation in your control cabinet. The wire size is determined by your installed terminal base. Always follow local electrical codes for wiring practices.

Electronic Protection Features

Each output channel on the 1794-OB32P is electronically protected. This protection guards against temperature overloads and current shocks. When an overload occurs, the affected channel shuts down automatically. After the fault clears, the channel recovers without fuse replacement. Thus, this module reduces maintenance downtime significantly. The external DC supply voltage range is 10 to 31.2V DC. This range includes 5% AC ripple. The external DC supply current ranges from 103 to 273 mA.

Installation Guidelines for the 1794-OB32P

First, mount the compatible terminal base unit on a DIN rail. Second, snap the 1794-OB32P onto the terminal base. Always disconnect power before installing or removing the module. Third, connect your field devices to the appropriate terminals. The 1794-OB32P requires an external 24V DC power supply. Ensure this supply can handle the total load current. Group channels 0-15 together on one power source. Likewise, group channels 16-31 on a separate source. This separation maximizes the current capacity of each group. Finally, verify all connections before applying power.

Package Contents

• One Allen-Bradley 1794-OB32P Flex I/O Output Module

• One product data sheet with quick reference guide

• One label sheet for channel identification

• No terminal base unit included (sold separately)

Frequently Asked Questions (FAQ)

Q1: What terminal base units work with the 1794-OB32P?
A: The 1794-OB32P works only with 1794-TB32 and 1794-TB32S terminal bases. Therefore, check your existing base compatibility first.

Q2: Why do channels 0-15 and 16-31 have different current totals?
A: The 1794-OB32P provides 6 Amperes for channels 0-15 and 8 Amperes for channels 16-31. Thus, distribute high-current loads to channels 16-31 whenever possible.

Q3: What happens when an output channel overloads on the 1794-OB32P?
A: The electronic protection on the 1794-OB32P shuts down the affected channel automatically. After the overload clears, the channel recovers without fuse replacement.

Q4: Can I use the 1794-OB32P with AC loads?
A: No, the 1794-OB32P is designed for DC loads only. It operates at 24V DC nominal voltage. For AC loads, consider other Flex I/O output modules.

Q5: How do I know if the 1794-OB32P is working correctly?
A: The 1794-OB32P has thirty-two yellow status indicators. Each LED lights up when its corresponding output is ON. Therefore, a quick visual inspection confirms operation.