The Allen-Bradley 1756-CP3 is a dedicated serial programming cable designed for the ControlLogix and SLC 500 controller families. It serves as the physical communication link between a controller's front-facing RS-232 port and a computer or other Data Terminal Equipment (DTE). This cable is essential for local programming, firmware updates, and troubleshooting when network-based communication, such as Ethernet or ControlNet, is unavailable or not yet configured.
Features
Right-Angle Connector: Features a right-angle 9-pin female D-shell connector at the controller end, allowing for chassis door closure during operation.
Null-Modem Configuration: Engineered for point-to-point serial communication, bridging transmit and receive pins between the PLC and PC.
Compatibility: Designed for use with Logix 5550, 5560, and 5570 controllers, as well as SLC 5/03, 5/04, and 5/05 modular processors.
Standard Interface: Compatible with standard PC COM ports or high-quality USB-to-Serial adapters.
Technical Specifications
Brand
Allen-Bradley
Product Line
ControlLogix / SLC 500
Cable Type
Serial RS-232 Programmer Cable
Length
10 feet (3 meters)
Connector A
9-pin D-shell (Right-Angle Female)
Connector B
9-pin D-shell (Straight Female)
Protocol
DF1 (RS-232)
Installation Guidelines
Ensure the controller is powered or in a safe state before connecting or disconnecting the cable to prevent potential communication errors.
The right-angle connector should be seated fully into the controller's front-facing port to ensure a secure connection.
Avoid routing the cable near high-voltage power lines or heavy electromagnetic interference (EMI) sources to maintain signal integrity during data transfer.
If using a USB-to-Serial converter, ensure the driver is correctly mapped to the COM port in your programming software (e.g., RSLinx).
FAQ
Is this cable compatible with USB ports?
The 1756-CP3 features a 9-pin serial connector. To use it with a modern computer lacking a native COM port, you must use a high-quality USB-to-Serial converter. Ensure the converter supports the DF1 protocol.
Can I keep this cable connected while the ControlLogix chassis door is closed?
Yes. The 1756-CP3 is specifically designed with a right-angle connector at the controller end to provide the necessary clearance for the chassis door to close while the cable is attached.
