Allen-Bradley 1771-IBDK Digital Input Module

Allen-Bradley 1771-IBDK Digital Input Module

Configured for discrete DC signal acquisition in PLC-5 I/O systems, the Allen-Bradley 1771-IBDK (1771-IBDK Digital Input Module) provides direct physical/electrical execution for 16-point sinking input monitoring. The module interfaces field devices such as switches and sensors through 10-30 VDC inputs with opto-isolation, configurable input filtering, and LED channel indication.

Hardware Specifications

EtherNet/IP and PLC-5 I/O Signal Integration

The 1771-IBDK operates as a PLC-5 discrete input interface module, transferring field contact status into the controller backplane through the 1771 I/O architecture. The module uses optoelectrical isolation between field input circuits and internal logic circuits to reduce the effect of electrical transients. The selectable input delay filtering provides configurable response characteristics for mechanical contact signals and industrial sensor inputs.

The conformal coating applied to the circuit assembly provides additional protection against environmental contaminants such as moisture and dust. LED indicators on each input point provide local verification of signal states during commissioning and maintenance activities.

Frequently Asked Questions

Q: What type of field signals can the 1771-IBDK process?
A: The module accepts 10-30 VDC discrete sinking input signals from field devices including switches, sensors, and contact-based devices.

Q: Does the 1771-IBDK provide electrical isolation between field wiring and PLC logic?
A: Yes. The module uses optoelectrical isolation with input filtering between the field input channels and internal module circuitry.

Q: What is the function of the selectable input delay filter?
A: The selectable 1 ms or 6 ms filter setting controls input response timing and helps manage signal noise or mechanical contact transitions.

Field Installation Guidelines

Install the 1771-IBDK module into a compatible PLC-5 1771 I/O chassis following the chassis installation procedure. Verify that field wiring polarity and DC input voltage levels match the module specifications before applying power.

Route DC signal wiring separately from high-voltage power conductors and high-current switching circuits to reduce electrical interference. Connect cable shields according to site grounding practices, normally at a single designated grounding point to prevent ground loop currents.

Use the specified wiring arm connection for field termination and verify LED channel operation during commissioning. Confirm that the module is correctly seated in the chassis and that the backplane connection is free from contamination before system startup.