Product Overview
When field signals need reliable monitoring, the Allen-Bradley 1771-IBD Digital DC Input Module delivers precise, high-speed detection for your control system. As part of the 1771 product bulletin, this single-slot module interfaces with switches, sensors, and auxiliary contacts, translating their ON/OFF states into logic signals your PLC can act on.
The 1771-IBD features sixteen (16) 10-30VDC sink input channels, with a minimum ON-state voltage of 10VDC and a maximum OFF-state voltage of 5VDC. It mounts in any 1771 I/O chassis except the 1771-A1, -A2, and -A4 models, making it a versatile choice for many legacy and current Allen-Bradley systems.
Technical Specifications
Below are the key specifications for the Allen-Bradley 1771-IBD, sourced directly from the manufacturer's data.
| Parameter |
Value |
| Manufacturer |
Rockwell Automation |
| Module Type |
Digital DC Input Module |
| Part Number / Catalog No. |
1771-IBD |
| Brand |
Allen-Bradley |
| Series |
1771 Product Bulletin |
| No. of Inputs |
Sixteen (16) Inputs |
| Operating Voltage Range |
10 to 30VDC |
| Input Delay Time, OFF to ON |
1 ms |
| Input Delay Time, ON to OFF |
1 ms or 6 ms |
| Power Dissipation |
7.3 Watts (max.), 1.0 Watts (min.) |
| Thermal Dissipation |
24.7 BTU/hr (max.), 3.4 BTU/hr (min.) |
| Backplane Current at 24 Volts |
130mA @ 5V dc +5% |
| Compatible chassis |
All 1771 I/O chassis except 1771-A1, -A2, and -A4 |
| Keying |
Between 10 and 12; Between 16 and 18 |
| Field Wiring Arm Cat. No. |
1771-WH |
| Wiring Arm Screw Torque |
7-9 inch-pounds |
| Voltage Category |
10 to 60 Volts DC, Sink (Source Load) |
| Max DC Off-State Current |
2.0 Miliamperes |
| Typical AC Signal Delay (Off) |
20 (+/- 15) milliseconds |
| Dimensions |
3.5 x 6.5 x 2.0 inches (89 x 165 x 51 millimeters) |
| UPC |
10662468100660 |
Key Features and Benefits
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16 Discrete Inputs: Monitor multiple field devices simultaneously, reducing the need for multiple modules.
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Wide Operating Range: Accepts 10-30VDC signals, compatible with a broad range of sensors and switches.
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Fast Response: 1ms OFF-to-ON delay ensures quick detection of state changes for time-critical processes.
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LED Indicators: Eighteen LEDs provide immediate visual status of each input and module health.
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Removable Wiring Arm: The 1771-WH field wiring arm simplifies installation and maintenance—no need to disconnect wires when replacing the module.
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Optoelectrical Isolation: Protects the backplane and processor from electrical transients.
Industry Applications
The Allen-Bradley 1771-IBD excels in applications where reliable discrete sensing is essential. Typical use cases include:
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Manufacturing Lines: Monitor limit switches and proximity sensors on conveyor systems to track product flow and detect jams.
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Packaging Machinery: Interface with photo-eyes and pushbuttons to control machine cycles and safety interlocks.
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Material Handling: Read status from auxiliary contacts on motor starters and valves to confirm equipment state.
Installation & Setup Guidance
Installing the 1771-IBD is straightforward. Follow these steps for a trouble-free setup:
- Ensure the chassis is powered down before inserting or removing the module.
- Slide the module into an available slot in a compatible 1771 I/O chassis (not 1771-A1, -A2, or -A4).
- Set the keying bands between pins 10 and 12 (lower connector) and between pins 16 and 18 (upper connector) to prevent incorrect insertion.
- Attach the field wiring arm (1771-WH) and torque the screws to 7-9 inch-pounds.
- Wire field devices to the appropriate terminals, observing polarity for DC sink inputs.
- Power up the chassis and verify the LED indicators reflect the input states.
Maintenance & Reliability
Regular maintenance of the 1771-IBD ensures long service life. Periodically inspect the module for dust or debris, which can affect heat dissipation. Check that all wiring connections remain tight and that the wiring arm is secure. The module’s low power dissipation (max 7.3W) reduces heat stress, and its optoelectrical isolation minimizes the risk of damage from transients. With minimal moving parts, the 1771-IBD offers high reliability, reducing downtime and maintenance costs over its lifecycle.
Compatibility & Integration
The 1771-IBD integrates seamlessly with any 1771 I/O chassis (except the noted models) and works with PLC processors that support the 1771 backplane. It supports ½, 1, and 2-slot I/O addressing, giving you flexibility in configuring your system. The module is compatible with source-switching devices such as dry-contact switches, electro-mechanical transmitters, and panel devices like selector switches and pushbuttons. For new installations, verify that your existing backplane and power supply can handle the 130mA backplane current draw.
Selection Guide & Purchasing Advice
Before purchasing, confirm that your system requires a 16-input DC sink module and that your chassis is compatible (not 1771-A1, -A2, -A4). Check the operating voltage of your field devices to ensure they fall within 10-30VDC. The 1771-IBD comes with a 1771-WH wiring arm; if you need a replacement, the 1771-WH is the correct part. For reliable sourcing, PLC Source PRO offers genuine Allen-Bradley 1771-IBD modules with fast shipping and competitive pricing. Ensure you order the correct part number to avoid compatibility issues.