Product Overview

The Allen Bradley 1790-15CMCBL CompactBlock LDX I/O Expansion Cable is an accessory designed for modular I/O installations in the Bulletin 1790 product family. Its primary function is to establish the expansion connection between compatible CompactBlock LDX base blocks and expansion blocks.

Compared with the standard 7 cm replacement ribbon cable, this 15 cm version provides additional reach for more flexible module positioning. It is particularly useful for vertical mounting arrangements, where expansion blocks are installed in a back-to-back configuration and alternately positioned right-side up and upside down. In supported configurations, the longer cable allows up to 7 cm of spacing between blocks.

The 1790-15CMCBL is a dedicated interconnection accessory rather than an independent communication or I/O device. It does not replace the external DeviceNet network cable. Proper installation requires checking module compatibility, connector orientation, and the mechanical arrangement of the complete I/O assembly.

For industrial maintenance, system expansion, and legacy equipment support, this cable provides a practical solution for maintaining the physical connection between compatible CompactBlock LDX modules.

Technical Specifications

Parameter	Specification
Brand	Allen Bradley
Model	1790-15CMCBL
Product Series	CompactBlock LDX
Product Type	I/O Expansion Cable
Cable Type	Ribbon Cable
Cable Length	15 cm / 5.91 in
Main Function	Connects Compatible I/O Base and Expansion Blocks
Application	CompactBlock LDX I/O Expansion
Installation	Horizontal and Vertical Module Arrangements
Maximum Supported Block Spacing	Up to 7 cm
Protection Rating	IP20
Operating Temperature	0–60°C
Storage Temperature	-40–85°C
Relative Humidity	Up to 90% RH
Shipping Weight	3 kg / 6.61 lb

Recommended Related Models

The following Allen Bradley products are relevant to CompactBlock LDX expansion and connection applications:

1790-7CMCBL – CompactBlock LDX I/O Replacement Ribbon Cable, 7 cm.
1790-0B16X – CompactBlock LDX 16-Point Sourcing Output Expansion Block.
1790-0V16X – CompactBlock LDX 16-Point Sinking Output Expansion Block.
1790-0W8X – CompactBlock LDX 8-Point Relay Output Expansion Block.
1790-16BV0X – CompactBlock LDX 16-Point Universal Input Expansion Block.

These products serve different functions within the CompactBlock LDX system. Verify the cable and module requirements before selecting components for an expansion project.

Popular Related Models

1790-7CMCBL – Allen Bradley CompactBlock LDX 7 cm Ribbon Cable.
1790-15CMCBL – Allen Bradley CompactBlock LDX 15 cm Expansion Cable.
1790-0B16X – Allen Bradley CompactBlock LDX Digital Output Expansion Block.
1790-0V16X – Allen Bradley CompactBlock LDX Digital Output Expansion Block.
1790-0W8X – Allen Bradley CompactBlock LDX Relay Output Expansion Block.

When purchasing the 1790-15CMCBL, confirm the cable length and compatibility with the existing CompactBlock LDX assembly. This helps ensure correct module positioning and reliable interconnection during installation.

Applications

The Allen Bradley 1790-15CMCBL CompactBlock LDX I/O Expansion Cable is a 15 cm ribbon cable designed to connect compatible CompactBlock LDX I/O base blocks and expansion blocks. It provides additional connection length for installations where standard expansion cable length is insufficient.

Typical applications include:

Distributed I/O Expansion: Connects compatible base blocks and expansion blocks within a CompactBlock LDX assembly.
Vertical Module Installation: Supports back-to-back module arrangements where additional cable reach is required.
Control Panel Assembly: Provides greater flexibility when positioning I/O blocks inside industrial control cabinets.
Machine Automation: Maintains the expansion connection between distributed I/O modules.
Industrial Equipment Upgrades: Supports modifications to existing CompactBlock LDX installations.
Legacy System Maintenance: Provides a replacement cable for compatible Allen Bradley I/O assemblies.

Key Features and Advantages

1. 15 cm Ribbon Cable Design

The 1790-15CMCBL provides a 15 cm connection length, offering additional reach compared with the standard 7 cm replacement ribbon cable.

2. Flexible Module Arrangement

The longer cable supports different module mounting arrangements, including vertical configurations that require additional spacing between blocks.

3. CompactBlock LDX Compatibility

Designed specifically for the CompactBlock LDX I/O product family, it provides the interconnection required between compatible base and expansion blocks.

4. Improved Installation Flexibility

The cable allows up to 7 cm of spacing between blocks in supported configurations, helping accommodate different panel layouts.

5. Simplified I/O Expansion

It provides a dedicated ribbon-cable connection for expanding compatible I/O assemblies without requiring a separate external communication cable.

6. Industrial Installation Design

With an IP20 protection rating and a specified operating temperature range, the cable is intended for suitable industrial control-panel environments.

Technical FAQs

Q1: What is the Allen Bradley 1790-15CMCBL used for?

It is used to connect compatible CompactBlock LDX I/O base blocks and expansion blocks through an internal ribbon-cable interface.

Q2: What is the cable length?

The cable is 15 cm (approximately 5.91 inches) long.

Q3: What is the difference between the 1790-15CMCBL and 1790-7CMCBL?

The main difference is cable length. The 1790-15CMCBL is 15 cm long, while the 1790-7CMCBL is 7 cm long. The longer version provides additional flexibility for module positioning.

Q4: Can this cable be used for vertical module mounting?

Yes. It is intended for vertical back-to-back arrangements where the blocks are alternately positioned right-side up and upside down.

Q5: How much spacing can the longer cable accommodate?

In supported mounting configurations, the 15 cm cable allows up to 7 cm of spacing between adjacent blocks.

Q6: Can the cable connect multiple expansion blocks?

It provides an individual connection between compatible blocks. CompactBlock LDX base modules can support multiple expansion blocks, subject to the specific base-module limitations.

Q7: Is the 1790-15CMCBL a DeviceNet communication cable?

No. It is an I/O expansion ribbon cable used for interconnecting CompactBlock LDX blocks. It should not be confused with the external DeviceNet network cable.

Q8: What is the IP protection rating?

The cable is specified with an IP20 rating. It is intended for installation in an appropriate protected environment rather than direct exposure to water or outdoor conditions.

Q9: What should be checked before installing the cable?

Confirm that the connected modules belong to the compatible CompactBlock LDX family, inspect the connector orientation, and follow the manufacturer's installation instructions.

Q10: Can the 1790-15CMCBL replace the standard 7 cm cable?

It can be used where the longer cable is supported and additional reach is needed. Check the module arrangement and connector requirements before replacing the original cable.

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