Product Introduction

The Allen Bradley 1747-C20 Programming/Communication Cable is a 20-foot replacement cable designed for communication connections in Allen Bradley SLC 500 automation systems. It is used to connect compatible peripheral equipment, including an interface converter or Data Table Access Module, to an SLC 500 controller.

In a DH-485 communication arrangement, the 1747-C20 provides an extended connection distance compared with the standard 1747-C10 6-foot cable. It is particularly useful when a programming interface or peripheral device needs to be positioned farther from the controller.

The cable is commonly associated with the 1747-AIC Isolated Link Coupler, 1747-PIC Personal Computer Interface Converter, and 1747-DTAM-E Data Table Access Module. The exact connection arrangement depends on the connected equipment and controller configuration.

For maintenance and replacement projects, verify the cable catalog number and peripheral interface before installation. The 1747-C20 should not be confused with the 1747-CP3, which is used for a different RS-232 programming connection.

Technical Specifications

Parameter	Specification
Brand	Allen Bradley
Model	1747-C20
Product Series	SLC 500
Product Type	Programming/Communication Cable
Cable Length	20 ft (6.09 m)
Communication Application	DH-485 peripheral connection
Compatible Accessories	1747-AIC, 1747-PIC, 1747-DTAM-E
Primary Function	Processor-to-peripheral communication
Operating Temperature	0–60°C (32–140°F)
Shipping Weight	3 kg / 6.61 lb
Lifecycle Status	Discontinued

Recommended Related Models

The following cables and communication accessories are relevant to SLC 500 programming and networking applications:

Model	Product Description
1747-C10	SLC 500 6-Foot Programming/Communication Cable
1747-C11	SLC 500 Processor-to-Isolated Link Coupler Cable
1747-C13	SLC 500 Communication Cable
1747-CP3	SLC 500 RS-232 Programming Cable
1747-AIC	SLC 500 Isolated Link Coupler
1747-PIC	SLC 500 Personal Computer Interface Converter
1747-DTAM-E	SLC 500 Data Table Access Module

These components serve different communication functions. Confirm the required connection path and interface before choosing a replacement.

Popular Related Models

Other Allen Bradley products commonly used in SLC 500 automation systems include:

1747 Series: SLC 500 processors, communication accessories, and specialty modules.
1746 Series: Digital and analog I/O modules for SLC 500 controllers.
1784 Series: Allen Bradley programming and communication interface products.
1761 Series: MicroLogix communication cables and interface accessories.

The 1747-C20 was discontinued by Rockwell Automation effective December 31, 2022. When sourcing this legacy cable, verify the complete catalog number, connector condition, and compatibility with the intended SLC 500 peripheral equipment.

Applications

The Allen Bradley 1747-C20 Programming/Communication Cable is an accessory for compatible Allen Bradley SLC 500 programmable logic controller systems. It provides a physical connection between an SLC 500 processor and supported programming or communication peripherals.

With a cable length of 20 feet, it is useful in control cabinets and maintenance environments where the connected programming equipment needs to be positioned farther from the PLC.

Typical applications include:

PLC Programming: Connects compatible SLC 500 processors to supported programming interface equipment.
Controller Communication: Establishes a physical communication connection with compatible peripheral devices.
System Maintenance: Supports program access, controller diagnostics, and troubleshooting activities.
Industrial Control Panels: Provides additional cable reach between the processor and programming accessories.
Legacy PLC Support: Serves as a replacement cable for existing SLC 500 installations.

Key Features and Advantages

SLC 500 System Compatibility: Designed for specified programming and communication arrangements within the Allen Bradley SLC 500 platform.

Extended 20-Foot Length: Provides approximately 6.1 meters of cable reach, offering greater flexibility when connecting programming equipment.

Programming Access: Supports communication between compatible processors and peripheral programming devices.

Maintenance Convenience: Helps technicians access PLC communication connections during commissioning, inspection, and troubleshooting.

Catalog-Specific Replacement: Provides a replacement option for installations originally configured with the 1747-C20 cable.

Technical FAQs

Q1: What is the primary function of the 1747-C20?

A: It is a programming and communication cable used to connect compatible SLC 500 processors with supported peripheral equipment.

Q2: What is the cable length?

A: The specified cable length is 20 feet, approximately 6.1 meters.

Q3: Which devices can be connected using the 1747-C20?

A: Its application depends on the supported SLC 500 processor and peripheral connection arrangement. Confirm the device compatibility in the relevant Rockwell Automation documentation.

Q4: Can the 1747-C20 connect a computer directly to an SLC 500 processor?

A: Not necessarily. A compatible interface converter or programming accessory may be required, depending on the processor model and communication port.

Q5: Is the 1747-C20 interchangeable with the 1747-C10?

A: Both are programming/communication cable catalog numbers, but their specified lengths differ. Confirm the required cable configuration and connection compatibility before substitution.

Q6: Can the 1747-C20 be used with every SLC 500 processor?

A: Compatibility depends on the processor and peripheral interface. Different SLC 500 processors support different communication arrangements, so the catalog number alone should not be used to determine compatibility.

Q7: Does the cable provide power to connected communication equipment?

A: Power availability depends on the cable's intended connection arrangement. Do not assume that it supplies power to every connected device; check the applicable wiring documentation.

Q8: Can a damaged cable cause intermittent PLC communication?

A: Yes. Broken conductors, loose connectors, damaged insulation, or poor contact can interrupt communication or cause intermittent connection failures.

Q9: What should be checked if the PLC cannot communicate with programming equipment?

A: Inspect the cable and connectors, confirm the correct communication interface, check the peripheral device, and verify the programming software's communication settings.

Q10: Can an ordinary serial or Ethernet cable replace the 1747-C20?

A: Not without verifying the electrical interface, connector arrangement, and pinout. A cable with similar connectors may not provide the required communication connection.

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