Allen-Bradley 1492-ACABLE025UB Pre-wired Cable

The Allen-Bradley 1492-ACABLE025UB, also cataloged as the 1492-ACABLE025UB Pre-wired Cable, operates as a dedicated hardware component for signal interconnection between 1756-IF16 analog input modules and external field wiring terminals. Configured with 20 conductors of #22 AWG shielded wire, the assembly provides a 2.5 meter physical path for analog current signals, terminating in a 1756-TBCH connector on the module side and a 25-pin D-shell connector on the interface module (AIFM) side.

Hardware Specifications

Profinet / EtherNet/IP Deterministic Networks

Signal integrity within the 1756-IF16 analog loop relies on the impedance characteristics of the interconnect cable. The 1492-ACABLE025UB incorporates shielding to minimize electromagnetic interference (EMI) that could affect backplane bus communication velocity and analog-to-digital conversion accuracy. While this cable is a passive component, it must be routed to avoid crosstalk with high-voltage AC lines. Proper termination of the cable shield at the designated ground lug is required to maintain the signal common-mode rejection ratio specified for the ControlLogix I/O platform. Firmware flash compatibility of the connected I/O module ensures that channel scaling and input current readings remain synchronized with the controller's control loop cycle.

Frequently Asked Questions

Q: Can this cable be used with non-current input modules?

A: The 1492-ACABLE025UB is specifically mapped for the 1756-IF16 (S-ended current) input module. Usage with voltage-mode modules may result in signal mismatch or improper channel configuration.

Q: Is it permissible to extend the length of this 2.5 meter cable?

A: No. Extending the cable length beyond the factory-defined 2.5 meters introduces unacceptable resistance and capacitance, which can degrade signal accuracy and increase susceptibility to noise, violating standard analog instrumentation loop practices.

Field Installation Guidelines

• Connector Seating: Ensure the 1756-TBCH connector is fully seated into the 1756-IF16 module interface. Verify that the locking latch is engaged to prevent intermittent disconnections caused by vibration.
• Cable Routing: Maintain a minimum separation of 150 mm between the analog cable and any high-power AC or DC control wiring. Use dedicated wireways for signal cabling to prevent induced noise.
• Shielding Grounding: The cable shield must be connected to a low-impedance earth ground at the control cabinet entry point. Avoid creating ground loops by ensuring the shield is not grounded at the field device end unless specifically required by the loop schematic.
• Mechanical Stress: Do not subject the cable to tension. Ensure sufficient slack is provided near the connector entry points to allow for thermal expansion and module removal without straining the wire terminations.