1794-ADN Allen-Bradley Flex I/O DeviceNet Adapter

1794-ADN Allen-Bradley Flex I/O DeviceNet Adapter Module

Product Introduction

The 1794-ADN module from Allen-Bradley is a dedicated DeviceNet adapter that serves as the gateway for the distributed Flex I/O system. This adapter enables seamless communication between a central DeviceNet scanner and up to eight discrete, analog, or specialty I/O modules. It integrates the Flex I/O rack directly into a DeviceNet network for efficient data exchange. Additionally, its flexible mounting options and robust design make it suitable for various industrial applications.

Specifically, this adapter processes input data from field devices and delivers output commands from the controller with minimal latency. It uses the proven DeviceNet protocol to ensure reliable performance. The single DeviceNet port on the 1794-ADN uses an open 5-pin or 10-pin linear plug for straightforward connectivity. Furthermore, users can configure the node address using the built-in thumbwheel switches. This module operates from an external 24V DC supply.

Key Technical Specifications

This communication adapter includes several critical parameters for proper system design. For instance, it offers selectable Communication Rates of 125KB, 250KB, or 500KB. The module's Input Voltage Range is between 19.2 to 31.2 Volts DC, with a nominal rating of 24 Volts DC. Additionally, it handles an Inrush Current of 14A for 5 ms during power-up. The Flexbus Output Current, which powers the connected I/O modules, can reach a maximum of 640 mA at 5 Volts DC.

The 1794-ADN also provides visual diagnostics through its built-in LED indicators. Specifically, it features a Mod/Net Status LED and an I/O Status LED, both displaying red or green states. Furthermore, the electrical isolation is robust, with an Isolation Voltage of 50 Volts Continuous, type-tested at 1930 Volts DC for 60 seconds. The power consumption is 90 mA maximum from the DeviceNet network, with a maximum current draw of 400 mA at 24 VDC.

Mechanical and Environmental Ratings

Environmental Limits

The 1794-ADN is built to withstand demanding industrial conditions. Its Operating Temperature ranges from 0 to 55 °C (32 to 131 °F), with a Storage Temperature range of -40 to 85 °C (-40 to 185 °F). Furthermore, it operates reliably in 5 to 95% non-condensing relative humidity.

Mechanical Stress Tolerance

This adapter is exceptionally durable against physical stress. It meets the IEC 68-2-6 standard for Vibration, rated at 5 g @ 10-500 Hz. For shock, it withstands an Operating Shock of 30 g peak acceleration with an 11 ms pulse width. It also endures a non-operating shock of 50 g. Consequently, the 1794-ADN remains stable in applications with significant vibration.

Power and Thermal Management

Efficient power management is crucial for the 1794-ADN. Its Power Dissipation is rated at 7.6W maximum at 19.2 Volts DC. Correspondingly, its Thermal Dissipation is 26 BTU/hour at 19.2 Volts DC. Therefore, this module generates moderate heat that must be accounted for in the panel design. Users should ensure adequate airflow around the module to maintain the surrounding temperature within the specified limit.

Installation Guidelines

Mounting Options

Primarily, the 1794-ADN is designed for DIN Rail mounting. However, it also supports Panel Mounting for flexible installation. Its compact dimensions, measuring 3.7 x 3.6 x 3.4 inches, help it fit neatly in crowded cabinets. Remember that the adapter has an open-type enclosure. Hence, it requires an appropriate IP-rated cabinet for protection against dust and direct contact.

DeviceNet and Flexbus Connections

For network connections, the adapter uses a single DeviceNet port with an open 5-pin or 10-pin linear plug. Users must connect this to a Belden YR-29832 cable or an equivalent. Furthermore, the module connects to the Flex I/O system via the terminal base units. It supports a maximum of eight terminal bases and thus a maximum of eight I/O modules. The 1794-ADN must be installed as the leftmost module in the Flex I/O rack.

Addressing and Configuration

The 1794-ADN includes built-in thumbwheel switches for node address configuration. Users can set valid addresses from 00 to 63 using the minus (-) and plus (+) buttons. The baud rate is automatically detected during power-up. This feature simplifies installation and reduces setup time.

Packaging and Shipping Information

All units of the 1794-ADN are carefully packaged to prevent static or physical damage. The package includes the adapter module itself. However, the packaging does not include installation manuals, mounting hardware, or terminal base units. We professionally pack the module in anti-static material and secure it for shipping. The shipping weight is approximately 0.22 kg (7.76 oz).

• Shipping Carriers: FedEx, UPS, DHL

• Warranty and Certificates: Not included in the package

Frequently Asked Questions (FAQ)

1. How many Flex I/O modules does the 1794-ADN support?
It supports up to eight Flex I/O modules of any combination, including discrete, analog, and specialty modules.

2. What communication speeds does the 1794-ADN offer?
This adapter supports selectable data transmission rates of 125 Kbps, 250 Kbps, and 500 Kbps.

3. How do I set the node address on the 1794-ADN?
Use the built-in thumbwheel switches on the module. Valid settings range from 00 to 63, adjustable with the minus (-) and plus (+) buttons.

4. What cable is recommended for the 1794-ADN?
The recommended cable is Belden YR-29832 or an equivalent third-party DeviceNet cable.

5. Can the 1794-ADN be panel mounted?
Yes, it supports both DIN rail mounting and panel mounting for flexible installation options.