Allen-Bradley 1771-IC 8-Channel DC Input Module 48V

Allen-Bradley 1771-IC Digital DC Input Module

Product Introduction

The Allen-Bradley 1771-IC is a digital DC input module from the reliable 1771 product family. This module provides eight (8) sinking input channels that operate within a 42-56VDC range. It is specifically designed for PLC-5 systems and interfaces with high-voltage DC field devices like limit switches, float switches, and photoelectric sensors.

Notably, the 1771-IC module features robust input filtering that limits and suppresses voltage transients. These transients often come from electrical noise or contact bounce. As a result, this filtering significantly reduces electrically-related downtime. Furthermore, it can double or even triple the product life of connected field devices.

The module arrives in a static-shield bag for protection against electrostatic discharge during handling. Additionally, it includes a conformal coating that shields its circuitry from moisture, dust, and chemical contaminants. This makes the Allen-Bradley 1771-IC well-suited for demanding industrial environments.

Technical Specifications

The 1771-IC module operates within a 42 to 56VDC range, making it ideal for higher-voltage DC control circuits. Its voltage category spans 10-60VDC as a sink-type (source load) configuration. The module draws a backplane current of only 74 mA at 5V DC, which is quite efficient for this class of I/O module.

Its maximum off-state current is specified at 3.7 mA. This low leakage current prevents false triggering from sensor leakage. Additionally, the module's built-in digital filter delivers a typical ON signal delay of 15 ms (±7 ms). For the OFF transition, the delay is typically 20 ms (±7 ms). These filtering delays effectively debounce noisy switch contacts and provide stable input readings.

The Allen-Bradley 1771-IC works seamlessly with both 2-wire and 3-wire devices. Compatible devices include DC proximity switches, limit switches, float switches, pushbuttons, photoelectric sensors, and selector switches. For 3-wire applications, ensure that the off-state leakage current does not exceed 4 mA for proper operation.

Mechanical & Environmental Data

This input module is built for industrial durability. Its compact dimensions are 3.5 x 6.5 x 2.0 inches (89 x 165 x 51 mm), occupying a single slot in your I/O rack. The conformal coating provides an additional layer of protection against harsh environmental conditions.

The module requires a field wiring arm with catalog number 1771-WN. This removable wiring arm significantly simplifies both installation and maintenance. For instance, you can wire the arm on your workbench and then attach it to the module. If the 1771-IC ever needs replacement, you simply detach the wiring arm from the old module. Then, attach it to the new one—no rewiring required.

This feature saves valuable time and reduces the risk of wiring errors. The wiring arm uses screw terminals for secure and reliable connections.

Installation Guidelines

Installing the Allen-Bradley 1771-IC is a straightforward process. First, ensure your 1771 chassis is powered off. This module is compatible with standard 1771 I/O chassis used in PLC-5 systems. Next, select an empty slot and insert the module firmly into the backplane.

After securing the module, attach the pre-wired 1771-WN field wiring arm. Connect your field devices according to the wiring diagram provided in the installation instructions. Finally, apply power to the chassis and verify that the module operates correctly.

The module supports standard 1771 addressing schemes. Each of the 8 input channels corresponds to a specific bit in the PLC data table, simplifying programming and troubleshooting.

Packaging List

• 1 x Allen-Bradley 1771-IC Digital DC Input Module

• 1 x 1771-WN Field Wiring Arm

• 1 x Installation Instructions Sheet

Shipping: We ship worldwide using FedEx, UPS, or DHL.

Frequently Asked Questions (FAQ)

1. What is the operating voltage range for the 1771-IC module?
The 1771-IC module has a DC operating voltage range of 42 to 56 Volts.

2. How many input channels does the 1771-IC have?
It has eight (8) input channels, each compatible with 2-wire and 3-wire DC devices.

3. What is the purpose of the input filtering on this module?
The digital filter suppresses electrical noise and contact bounce transients. This reduces downtime and extends the life of connected field devices.

4. Can I replace the 1771-IC module without rewiring?
Yes, you can. The module includes a removable 1771-WN wiring arm. Simply detach the arm from the old module and attach it to the new one.

5. What types of field devices work with the 1771-IC?
It works with DC proximity switches, limit switches, float switches, pushbuttons, photoelectric sensors, and selector switches.