Product Overview
The Allen-Bradley 1771-ID is a dual-rated, individually isolated input module from the 1771 product bulletin. Designed for demanding industrial environments, this module accepts six isolated 120VAC or 120VDC input channels, making it a versatile choice for monitoring discrete field devices such as limit switches, pushbuttons, selector switches, and float switches. With per-channel isolation, each input can operate at different voltage ratings, offering flexibility in mixed-voltage applications.
As part of the 1771 I/O family, the 1771-ID mounts directly into any 1771 I/O chassis, occupying a single slot. It ships with the 1771-WD field wiring arm, which simplifies modular wiring and replacement. The module's input filtering minimizes the effects of electrical noise and contact bounce, improving power quality and reducing downtime.
Technical Specifications
The following specifications are sourced directly from the manufacturer's data:
| Parameter |
Value |
| Manufacturer |
Rockwell Automation |
| Part Number |
1771-ID |
| Series |
1771 Product Bulletin |
| Number of Inputs |
6 inputs |
| Voltage Category |
120 Volts AC/DC |
| AC Operating Voltage |
92–138 Volts |
| DC Operating Voltage |
92–138 Volts |
| AC Input Frequency |
47–63 Hz |
| Nominal Input Current |
8 mA @ 120V AC; 8 mA @ 120V DC |
| Input Signal Delay (AC) |
24 (±10) ms on/off |
| Input Signal Delay (DC) |
10 (±4) ms on; 20 (±9) ms off |
| Backplane Current |
74 mA |
| Max AC Off-State Current |
1.7 mA |
| Max DC Off-State Current |
1.7 mA |
| Power Dissipation |
0.4–4.4 Watts |
| Thermal Dissipation |
1.3–15.0 BTU/hr |
| Keying Positions |
Between 4 and 6; Between 28 and 30 |
| Field Wiring Arm |
Cat. No. 1771-WD |
| Wiring Arm Screw Torque |
7–9 inch-pounds |
| Dimensions |
3.5 x 6.5 x 2.0 in (89 x 165 x 51 mm) |
Key Features & Benefits
-
Individual Channel Isolation: Each input is optically isolated, allowing mixed AC/DC operation and preventing ground loop issues.
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Wide Operating Range: Accepts 92–138V AC or DC, accommodating varying supply voltages.
-
Input Filtering: Reduces false triggering from electrical noise and contact bounce, enhancing system reliability.
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Simple Installation: Single-slot mounting in any 1771 I/O chassis with included 1771-WD wiring arm.
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Low Power Dissipation: Only 0.4–4.4W, minimizing heat buildup in the enclosure.
Industry Applications
The 1771-ID is ideal for isolated-circuit, multi-phase applications where reliable input sensing is critical. Common use cases include:
-
Material Handling: Monitoring limit switches on conveyors and automated guided vehicles.
-
Process Control: Reading float switches in tanks and hoppers for level monitoring.
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Machine Tool Control: Detecting pushbutton and selector switch states on control panels.
Thanks to its dual AC/DC rating and per-channel isolation, the 1771-ID excels in retrofit projects where legacy wiring may mix voltage types.
Installation & Setup Guidance
To install the 1771-ID, follow these steps:
- Ensure the 1771 I/O chassis is powered down.
- Insert the module into a single slot, aligning the keying bands at positions 4 and 6, and 28 and 30.
- Secure the field wiring arm (1771-WD) to the module. Torque the wiring arm screws to 7–9 inch-pounds.
- Wire input devices using 14 AWG stranded or solid copper wire with a maximum insulation thickness of 3/64 inch.
- Apply power and verify input status via the module's indicators.
When planning the chassis backplane load, include the 74 mA backplane current of the 1771-ID in your power budget to prevent overloading.
Maintenance & Reliability
The 1771-ID requires minimal routine maintenance. Periodically inspect wiring connections for tightness and signs of corrosion. Ensure the operating environment remains within specified limits: 0 to 60°C operating temperature, 5–95% relative humidity (non-condensing). The module's solid-state design and input filtering reduce wear, extending service life and minimizing unplanned downtime.
Compatibility & Integration
The 1771-ID is compatible with any 1771 I/O chassis and works with Allen-Bradley PLC processors that support the 1771 I/O architecture. It uses the 1771-WD field wiring arm for connections, and the module is keyed to prevent incorrect insertion. For new installations, verify that your chassis backplane can supply the required 74 mA per module.
Selection Guide & Purchasing Advice
Before purchasing the 1771-ID, confirm your system's voltage requirements (AC or DC) and the number of isolated inputs needed. Ensure your chassis has available slots and sufficient backplane capacity. The module ships with the 1771-WD wiring arm, so no additional accessories are required for basic operation.
PLC Source PRO offers genuine Allen-Bradley 1771-ID modules with fast, reliable shipping. We understand the critical nature of industrial spares, so every unit is tested and backed by our quality guarantee.