Product Introduction

The Allen Bradley 1790-8BV8VX CompactBlock LDX I/O Expansion Block is a 24V DC digital expansion module developed for distributed industrial automation applications. Its combination of 8 universal inputs and 8 sinking outputs allows one unit to handle a range of discrete field signals, making it useful in machinery and production systems where additional I/O capacity is required.

The universal input design supports both sinking and sourcing signal arrangements, providing flexibility when connecting compatible sensors and switching devices. On the output side, the module provides 8 sinking channels for controlling suitable DC loads. Input and output status indicators help maintenance personnel identify signal activity and simplify troubleshooting.

The 1790-8BV8VX connects to a compatible CompactBlock LDX base block as part of a distributed I/O assembly. Its 37-pin D-shell connection provides the interface for field I/O wiring, while the CompactBlock LDX architecture allows additional digital expansion blocks to be incorporated into supported systems.

This model is a discontinued product, with Rockwell Automation announcing September 30, 2023, as its discontinuation date. It may still be relevant for existing equipment maintenance, system restoration, and spare-parts procurement. Buyers should verify the product condition, exact catalog number, and hardware compatibility before purchasing.

Technical Specifications

Parameter	Specification
Brand	Allen Bradley
Model	1790-8BV8VX
Product Type	CompactBlock LDX I/O Expansion Block
I/O Configuration	8 Universal Inputs / 8 Sinking Outputs
Input Type	24V DC, Sinking or Sourcing
Output Type	24V DC, Sinking
Nominal Field Voltage	24V DC
Maximum Output Current	0.5 A per output
Maximum Current per Common	4.0 A
Input Indicators	8 Green Status Indicators
Output Indicators	8 Green Status Indicators
Communication Platform	DeviceNet CompactBlock LDX System
Connector	37-pin D-shell
Dimensions	104 × 42 × 52 mm
Weight	0.1 kg / 0.22 lb
Product Status	Discontinued

Recommended Related Models

The following Allen Bradley models belong to the CompactBlock LDX digital I/O product family and may be relevant when expanding, maintaining, or replacing an existing installation:

1790-8BV8BX – CompactBlock LDX expansion block with 8 universal inputs and 8 sourcing outputs.
1790-16BV0X – CompactBlock LDX expansion block with 16 universal digital inputs.
1790-0V16X – CompactBlock LDX expansion block with 16 sinking digital outputs.
1790-0B16X – CompactBlock LDX expansion block with 16 sourcing digital outputs.
1790-0W8X – CompactBlock LDX expansion block with 8 relay outputs.

Select the appropriate model according to the required input and output configuration, wiring arrangement, and system compatibility.

Popular Related Models

Other commonly referenced models in the Allen Bradley CompactBlock LDX range include:

1790-T8BV8VX – Terminal-block version with 8 universal inputs and 8 sinking outputs.
1790-T8BV8BX – Terminal-block version with 8 universal inputs and 8 sourcing outputs.
1790-T16BV0X – Terminal-block version with 16 universal inputs.
1790-T0V16X – Terminal-block version with 16 sinking outputs.
1790-T0B16X – Terminal-block version with 16 sourcing outputs.
1790-7CMCBL – CompactBlock LDX I/O expansion ribbon cable, 7 cm.
1790-15CMCBL – CompactBlock LDX I/O expansion ribbon cable, 15 cm.

For replacement and spare-parts purchasing, always compare the complete model number and connector configuration. Similar-looking CompactBlock LDX modules may have different output types or wiring arrangements.

Applications

The Allen Bradley 1790-8BV8VX CompactBlock LDX I/O Expansion Block is designed to extend the digital input and output capacity of compatible CompactBlock LDX distributed I/O systems. It combines 8 universal 24V DC inputs with 8 sinking outputs in one compact module, allowing industrial control systems to handle multiple field signals without requiring separate input and output expansion units.

Typical applications include:

Distributed Machine Control: Expands the number of digital signals available for monitoring sensors, switches, and controlling field devices.
Factory Automation: Supports discrete I/O requirements in production lines, assembly equipment, and automated machinery.
Packaging Systems: Provides additional signal interfaces for monitoring machine conditions and controlling compatible output loads.
Material Handling: Supports input monitoring and output switching in conveyors and material transfer equipment.
DeviceNet Automation Networks: Adds digital I/O capacity to compatible DeviceNet-based CompactBlock LDX installations.

The module is intended for light industrial environments where compact distributed I/O and straightforward field wiring are important.

Key Advantages and Features

1. Combined Input and Output Configuration

The 1790-8BV8VX integrates 8 universal inputs and 8 sinking outputs, providing a practical solution for applications requiring both signal acquisition and output control.

2. Flexible Universal Inputs

Its 8 input channels support sinking or sourcing input configurations. This flexibility allows the module to interface with different types of compatible 24V DC field devices.

3. Reliable Sinking Output Control

The 8 sinking outputs support the control of compatible DC loads. Each output has a maximum current rating of 0.5 A, subject to the module's common current limits and operating conditions.

4. Compact Installation Design

With compact dimensions, the module helps conserve cabinet space and simplifies the expansion of existing distributed I/O installations.

5. DeviceNet System Integration

Designed for use within the CompactBlock LDX platform, the expansion block works with a compatible base block to extend the available I/O points in a DeviceNet-based control system.

6. Individual Channel Indicators

Green status indicators provide visual information about input and output conditions, helping technicians check field signal activity during commissioning and maintenance.

Technical FAQs

Q1: What is the main function of the Allen Bradley 1790-8BV8VX?

It expands a compatible CompactBlock LDX I/O system by adding 8 universal digital inputs and 8 sinking digital outputs.

Q2: How many input channels does this module provide?

The module provides 8 digital input points. Each input supports sinking or sourcing configurations.

Q3: What type of outputs are available?

It provides 8 sinking DC outputs for controlling compatible field loads.

Q4: What is the nominal operating voltage?

The module uses a nominal 24V DC field supply. Actual operating voltage must remain within the specified electrical limits.

Q5: What is the maximum output current per channel?

The maximum output current is 0.5 A per output, with a maximum of 4.0 A per common. The load arrangement must comply with both limits.

Q6: Does the 1790-8BV8VX support DeviceNet communication directly?

It is an expansion block rather than a standalone DeviceNet network adapter. It operates as part of a compatible CompactBlock LDX system connected through a base block.

Q7: What connector does this model use?

The 1790-8BV8VX uses a 37-pin D-shell connector for its I/O connections.

Q8: Can this module be used with any CompactBlock LDX base block?

It is designed for compatible digital I/O base blocks. Thermocouple and RTD base blocks do not support digital expansion blocks. Confirm the base-block model and system configuration before installation.

Q9: How can technicians identify an output-channel problem?

Check the output status indicator, field power supply, wiring connections, common configuration, and connected load. Also verify that the output current does not exceed the specified limits.

Q10: What should be checked before replacing this module?

Confirm the complete catalog number, connector type, I/O configuration, field wiring, and compatibility with the installed CompactBlock LDX system. The replacement should also be checked against the original system configuration.

Look forward to your comments!Comment