Allen-Bradley 1790-T8BV8VX CompactBlock LDX Expansion Module

Product Overview

The Allen-Bradley 1790-T8BV8VX is a CompactBlock LDX expansion module designed for flexible system integration in industrial automation. Operating on a nominal 24V DC supply, this module provides 8 non-isolated inputs (sinking or sourcing) and 8 non-isolated sinking outputs. Its built-in DeviceNet communication port simplifies networking, reducing wiring costs and installation time. For engineers seeking a cost-effective I/O expansion solution, this module delivers reliable performance without unnecessary complexity.

Technical Specifications Breakdown

Key parameters for the 1790-T8BV8VX are listed below for quick reference:

Industry Applications

Cost-Efficient Machine Expansion

In packaging or material handling systems, the 1790-T8BV8VX adds I/O points without replacing the main controller. Its 8 universal inputs handle both sinking and sourcing sensors, reducing spare part inventory and associated costs. The 8 sinking outputs directly drive small actuators or indicators, minimizing external relay panels.

Remote I/O for Distributed Control

Using the DeviceNet port, this module integrates into distributed control architectures. This reduces long cable runs and lowers installation expenses. The compact screw-mount design fits into tight enclosures, saving panel space and cooling costs.

Upgrade from Obsolete Systems

When upgrading legacy I/O, the 1790-T8BV8VX offers a drop-in expansion path. Its 24V DC operation matches common industrial power supplies, avoiding transformer upgrades. The non-isolated design keeps component costs low while maintaining adequate performance for non-critical signals.

Installation & Setup Guidance

Mount the module using the screw mount design with M3.0 terminal block screws torqued to 7 lb-in maximum. Use copper or copper-clad aluminum conductors. Connect DeviceNet power to the base block at 24V DC nominal (11 to 28.8V DC range). Field power supply must be 24V DC nominal (10 to 28.8V DC). Ensure isolation voltage of 1250V AC rms between I/O and logic is maintained. The module is rated for operation up to 2,000 meters altitude.

Maintenance & Reliability

Inspect the module periodically for loose connections or environmental contamination. The green status indicators on each input and output provide immediate visual feedback for troubleshooting. Power dissipation is only 1.2 W maximum at 28.8V DC, keeping thermal stress low and extending component life. For reliable operation, keep the ambient temperature within standard industrial ranges and avoid condensation.

Compatibility & Integration

The 1790-T8BV8VX communicates via the built-in DeviceNet port, enabling seamless integration with Allen-Bradley controllers and other DeviceNet-compatible devices. It functions as an expansion module for the CompactBlock LDX series, allowing flexible I/O count adjustments. The 8 inputs accept both sinking and sourcing signals, while the 8 outputs are sinking type. Non-isolated design suits cost-sensitive applications where galvanic isolation is not critical.

Selection Guide & Purchasing Advice

When selecting the 1790-T8BV8VX, verify your system's DeviceNet configuration and power supply compatibility. AutoDCSTech stocks this module and can assist with availability and lifecycle status. Please verify current lifecycle status and availability with AutoDCSTech before ordering.

Troubleshooting & Common Issues

If inputs do not respond, check the input ON-state voltage (9.6V DC minimum) and ensure the sensor type matches sinking or sourcing mode. For output failures, verify the output ON-state voltage (10V DC minimum) and load current (0.5 A max per output, 4.0 A max per common). Off-state leakage up to 0.5 mA may cause false triggering in high-impedance loads. Use the green status indicators to quickly isolate faulty channels. If DeviceNet communication fails, check network power and termination.