Description

The Allen-Bradley 1771-IBD (Series B) is a 16-point DC digital input module operating across a voltage range of 10 to 30V DC within the 1771 I/O chassis system. It converts discrete DC signals from field devices into logic-level signals readable by the system processor across the backplane. The module accommodates both 2-wire input switches and 3-wire current-sourcing sensors, such as Bulletin 871 proximity switches.

The 1771-IBD includes a selectable off-delay filter time of either 1ms or 6ms via an internal jumper plug located on the printed circuit board. Front-panel visual status reporting is provided by one green Module Active indicator and 16 red input status indicators. Power is supplied directly via the 1771 I/O chassis backplane, eliminating the need for an external logic power connection.

Features

• 16 discrete input channels operating at 10 to 30V DC
• Selectable High-to-Low signal propagation off-delay filter time (1ms or 6ms)
• 1 green Module Active LED and 16 red input status LEDs for logic-side diagnostics
• Direct drive compatibility with 1771-OBN, 1771-OBD, 1771-OB, 1771-OQ, and 1771-OQ16 output modules
• Supports 2-wire devices and 3-wire current-sourcing sensors in sinking configuration
• Uses catalog number 1771-WH field wiring arm for module removal without disconnecting field wiring
• Keyed backplane connectors between pins 10-12 and 16-18

Applications

• Discrete DC input processing in 1771 I/O control systems
• Interfacing with 2-wire mechanical switches and pushbuttons
• Signal acquisition from 3-wire current-sourcing proximity sensors
• Direct module-to-module interlock wiring with compatible 1771 DC output modules

Ordering Information

Technical Specifications

Connections/Interfaces

Field devices connect to the module using the 1771-WH Field Wiring Arm.

Installation Guidelines

• Power Precaution: Disconnect power from the 1771 I/O chassis backplane and field wiring arm before installing or removing the module to prevent equipment damage or personal injury.
• Electrostatic Discharge (ESD): Wear an approved wrist-strap grounding device and avoid touching backplane connector pins or internal circuit components.
• Chassis Location: Insert the module into any slot in the 1771 I/O chassis except the leftmost slot, which is reserved for processors or adapters. Do not install in 1771-A1, 1771-A2, or 1771-A4 chassis.
• Backplane Keying: Place keying bands in the upper backplane connector between pins 10 and 12, and between pins 16 and 18.
• Filter Off-Delay Configuration: The off-delay filter time is preset to 1ms. To change to 6ms, slide the jumper plug on the top-left edge of the circuit board from the 1ms position to the 6ms position before installing the module.
• Wiring Execution: Connect input device lines to terminals 00 through 17 and connect DC common to Terminal E. Use stranded 14 or 16 gauge wire to minimize voltage drop. Tighten terminal screws on the 1771-WH wiring arm to 7-9 inch-pounds.

Compliance and Certifications

• CSA Certified (Class I, Division 2, Groups A, B, C, D)
• UL Listed
• CE Marked (EMC Directive 89/336/EEC per EN 50081-2 & EN 50082-2; Low Voltage Directive 73/23/EEC per EN 61131-2)