1771-ID Allen-Bradley 1771 Isolated Input Module

1771-ID Allen-Bradley Isolated AC/DC Input Module

Product Introduction

The Allen-Bradley 1771-ID is a dual-rated, isolated input module from the 1771 product bulletin. It provides six individually isolated input channels, each capable of operating at 120V AC or 120V DC nominal voltages. Specifically, the operating voltage range spans 92 to 138V AC (47-63 Hz) and 92 to 138V DC. Because each channel is isolated, they can operate at different voltage levels simultaneously if required. Furthermore, the 1771-ID includes input filtering to mitigate voltage transients from electrical noise and contact bounce, enhancing system reliability and reducing downtime.

Technical Specifications

The 1771-ID delivers robust performance with clearly defined electrical parameters. It consumes 74 mA of backplane current and has a power dissipation range of 0.4 to 4.4 Watts, with thermal dissipation from 1.3 to 15.0 BTU/hr.

Key Input Characteristics:

• Number of Inputs: 6 (isolated channels)

• AC Operating Voltage: 92-138V AC (47-63 Hz)

• DC Operating Voltage: 92-138V DC

• Nominal Input Current: 8 mA at 120V AC; 8 mA at 120V DC

• Off-State Current: 1.7 mA maximum (AC and DC)

• Opto-Electrical Isolation: 1500V AC (rms)

Input Signal Delay and Filtering

The 1771-ID incorporates input filtering that delays signal transitions, effectively reducing false triggers caused by noise or contact bounce. The signal delay times vary depending on the input type and transition direction.

Specifically, for AC inputs, the signal delay is nominally 24 ms (±10 ms) for both ON and OFF transitions. For DC inputs, the ON delay is 10 ms (±4 ms), while the OFF delay is 20 ms (±9 ms). This filtering improves power quality and extends the life of connected devices, making the 1771-ID particularly well-suited for applications with electrically noisy environments.

Mechanical and Environmental Specifications

The Allen-Bradley 1771-ID is designed for installation in any 1771 I/O chassis, occupying a single slot. Its dimensions are 89 x 165 x 51 mm (3.5 x 6.5 x 2.0 inches). The module operates reliably within a temperature range of 0 to 60°C and can be stored between -40 to 85°C, with a relative humidity of 5-95% noncondensing.

Keying positions for this module are between 4 and 6, and between 28 and 30. The field wiring arm, catalog number 1771-WD, is included with the module for convenient wiring connections. For terminating input devices, 14-gauge stranded or solid copper wire with a maximum insulation of 3/64 inches is recommended. The wiring arm screw torque should be between 7 and 9 inch-pounds.

Application and Compatibility

The 1771-ID is ideal for isolated-circuit multi-phase applications and is commonly used with float switches, limit switches, pushbuttons, and selector switches. Its individual channel isolation allows each input to be sourced from different voltage references, offering flexibility in complex control systems.

This module is compatible with any 1771 I/O chassis. When designing a system, ensure that the total backplane current consumption of all modules, including the 1771-ID, does not exceed the power supply capacity. With its filtering and isolation features, this module minimizes electrically-related downtime and enhances overall system performance and productivity.

Installation Guidelines

Proper installation of the 1771-ID ensures reliable operation in your 1771 I/O system.

1. Chassis Selection: First, verify that the 1771 I/O chassis has an available slot and sufficient backplane power capacity.

2. Keying Configuration: Next, set the keying positions to between 4 and 6, and between 28 and 30, to ensure correct module insertion.

3. Module Insertion: Then, insert the module into the selected slot and secure it firmly.

4. Wiring Arm Attachment: After that, attach the provided field wiring arm (1771-WD) to the module.

5. Wiring: Finally, connect the field devices to the wiring arm terminals using 14-gauge wire, observing the correct torque specifications (7-9 inch-pounds) for secure connections.

Packaging List

Each shipment of the Allen-Bradley 1771-ID includes the following items:

• 1 x Isolated AC/DC Input Module

• 1 x Field Wiring Arm (Cat. No. 1771-WD)

• 1 x Installation Instructions manual

Frequently Asked Questions (FAQ)

1. What voltage ranges does the 1771-ID input module support?
The Allen-Bradley 1771-ID supports both AC and DC inputs from 92 to 138V. AC inputs must be 47-63 Hz, while DC inputs operate from 92-138V DC.

2. How many input channels does the 1771-ID provide?
This module provides six individually isolated input channels, each capable of operating at different voltage levels if needed.

3. What is the purpose of the input filtering on the 1771-ID?
The filtering reduces the effects of voltage transients from electrical noise and contact bounce, improving power quality and minimizing false triggering for more reliable operation.

4. Which field wiring arm is compatible with the 1771-ID?
The 1771-ID uses the 1771-WD field wiring arm for all field device connections, which is included with the module.

5. What shipping carriers do you use for the 1771-ID module?
We ship this product using reliable global carriers such as FedEx, UPS, and DHL to ensure safe and timely delivery.