Product Overview of the Allen-Bradley 1794-OB16D

The Allen-Bradley 1794-OB16D is a high-performance Flex I/O digital output module. Specifically, it belongs to the diagnostic (D) series of the 1794 platform. This module detects open and shorted field devices or wiring. Therefore, it significantly reduces troubleshooting time for maintenance teams. The 1794-OB16D fits directly inside a terminal base unit. Consequently, it creates a secure connection between field devices and the I/O bus.

Key Technical Specifications of the 1794-OB16D

First, let us examine the output characteristics. The 1794-OB16D provides 16 nonisolated current sourcing outputs. The nominal output voltage is 24V DC. Furthermore, the on-state output voltage range spans from 10 to 31.2V DC. Each channel delivers a maximum on-state current of 500mA. Additionally, the module supports a total output current rating of 8.0A per module. The off-state leakage current reaches a maximum of only 0.5mA. Thus, this module ensures reliable switching performance.

The output signal delay is an impressive 0.5 ms. Therefore, the 1794-OB16D responds quickly to control commands. The maximum output delay time from on-to-off is just 0.1 ms. As a result, this module suits high-speed automation applications.

Electrical and Power Specifications

The 1794-OB16D draws a Flexbus current of 60mA at 5V DC. The external power supply requires 10 to 31.2V DC with a 5% AC ripple. The external current draw ranges from 56 to 78mA. Maximum power dissipation reaches 4.8W at 31.2V DC. Likewise, maximum thermal dissipation is 16.4 BTU/hr. at 31.2V DC. The isolation voltage rating is 50V. Consequently, this module operates efficiently without excessive heat generation.

Diagnostic Features and Status Indicators

The diagnostic capability sets the 1794-OB16D apart from standard modules. It detects, indicates, and reports open or shorted field wiring. Therefore, you can identify faults immediately without guesswork. The module features 16 yellow LED status indicators. Each channel has a corresponding LED for clear visual feedback. These LEDs show the output signal status for every channel. As a result, troubleshooting becomes much faster and more accurate.

Compatibility and Mounting Guidelines

The 1794-OB16D is compatible with several terminal base units. These include the 1794-TB3, 1794-TB3S, and 1794-TBKD. You can insert or remove the module under power. This is possible because the I/O module has no direct wiring. Therefore, you save valuable time during system maintenance. Furthermore, there is no need to restart the entire system after module replacement.

The 1794-OB16D installs easily using a DIN rail. Simply snap the module onto the DIN rail until it clicks. This mounting method ensures a secure and grounded connection. Moreover, the module supports various communication options. For example, it works with ControlNet, DeviceNet, EtherNet/IP, and Universal Remote I/O.

Environmental Specifications and XT Versions

The operating temperature range is 0 to 55 °C (32 to 131 °F) . The relative humidity range is 5 to 95% noncondensing. Therefore, the 1794-OB16D works reliably in most industrial environments. Additionally, XT versions of standard modules are available. These XT versions operate in extreme environments with wider temperature ranges. Consequently, they reduce panel and maintenance costs for harsh applications.

Installation Guidelines for the 1794-OB16D

First, select a compatible terminal base unit like the 1794-TB3. Mount the terminal base on a standard DIN rail securely. Then, snap the 1794-OB16D into the terminal base until fully seated. Always verify that external power is within the 10 to 31.2V DC range. Use proper wire gauges for the 500mA per channel current. Additionally, ensure the total module current does not exceed 8.0A. Finally, check the yellow LED indicators after power-up. These LEDs confirm correct output operation for each channel.

Package Contents

• One Allen-Bradley 1794-OB16D Flex I/O Digital Output Module

• One user manual with installation instructions

• One label sheet for channel identification

• Four dust covers for unused terminal base slots

Frequently Asked Questions (FAQ)

Q1: What diagnostics does the 1794-OB16D provide?
A: The 1794-OB16D detects open and shorted field devices or wiring. It then indicates these faults through LED status indicators. Therefore, you can locate wiring problems quickly.

Q2: Can I remove the 1794-OB16D while power is applied?
A: Yes, the 1794-OB16D supports removal under power. The module has no direct wiring to the terminal base. Consequently, you can replace it without system shutdown.

Q3: What terminal base units work with the 1794-OB16D?
A: The 1794-OB16D works with 1794-TB3, 1794-TB3S, and 1794-TBKD bases. Always choose a base that matches your wiring requirements.

Q4: What is the maximum output current per channel on the 1794-OB16D?
A: Each channel supports a maximum of 500mA on-state current. The total module current must not exceed 8.0A. Thus, distribute loads carefully across all 16 channels.

Q5: Does the 1794-OB16D work in extreme temperature environments?
A: Standard versions work from 0 to 55 °C (32 to 131 °F) . For extreme environments, use the XT version of this module. The XT version handles much wider temperature ranges reliably.