Allen-Bradley 1771-IA PLC-5 Input Module 8 Channel AC/DC

Allen‑Bradley 1771‑IA PLC‑5 Discrete Input Module

The 1771‑IA is a digital AC/DC input module for the PLC‑5 platform. It provides eight (8) isolated channels for 120V AC or 125V DC field devices. This module converts high‑level signals from pushbuttons, limit switches, and sensors into logic levels for the processor. It is a Series C unit that supports ½‑, 1‑, and 2‑slot I/O addressing.

This module uses optoelectrical isolation to protect the backplane from electrical transients. An integrated input filter reduces noise on field wiring. The front panel shows eight orange status LEDs for channel‑by‑channel visual indication.

Technical Specifications

• Brand: Allen‑Bradley / Rockwell Automation
• Model: 1771‑IA
• Module Type: Discrete AC/DC Input (8 channels)
• Voltage Category: 120V AC / 125V DC
• AC Operating Range: 87–138V AC
• DC Operating Range: 97–138V DC
• Nominal Input Current: 6.83mA @120V AC 50Hz; 7.9mA @120V AC 60Hz; 7.4mA @125V DC
• Off‑State Max Current: 2.8mA AC
• Typical Signal Delay (AC On/Off): 24ms ±10ms
• Typical Signal Delay (DC On): 10ms ±4ms
• Typical Signal Delay (DC Off): 20ms ±9ms
• Backplane Current Draw: 75mA @ 5V DC
• Power Dissipation: 10.7W max
• Thermal Dissipation: 36.5 BTU/hr
• Isolation: Optoelectrical, 1500V AC (1 min)
• Compatible Chassis: 1771‑AB through 1771‑A4B
• Slot Occupancy: Single slot
• Keying: Upper 10–12; Lower 4–6
• Wiring Arm: 1771‑WA (included)
• Dimensions: 3.5 × 6.5 × 2.0 in (89 × 165 × 51 mm)

Installation & Wiring

Install the 1771‑IA into any available slot of a 1771 I/O chassis with a PLC‑5 processor. Verify the chassis power supply capacity before installation. Use the supplied 1771‑WA wiring arm for all field terminations. This arm preserves wiring when you replace the module. For correct slot keying, position the upper key between pins 10 and 12, and the lower key between pins 4 and 6.

Configuration & Diagnostics

Configure the module using the PLC‑5 channel configuration utility. After configuration, the system automatically creates the corresponding bit in the binary data file. Each channel provides real‑time status via the front‑panel LED. The module supports built‑in input filtering to reduce nuisance trips from electrical noise. Diagnostic information is available through the processor’s data table.

Typical Applications

Use this module to interface AC/DC field devices such as:

• Pushbuttons and selector switches
• Limit switches and proximity sensors
• Motor starter auxiliary contacts
• Annunciators and alarm contacts
• On/off actuators and solenoid feedback

Compatibility & Standards

• Certifications: CSA, CSA Class I Div 2 Groups A–D, UL Listed, CE marked
• Addressing Support: ½‑slot, 1‑slot, 2‑slot I/O addressing
• Environmental: 0–60 °C operating; 5–95% RH non‑condensing
• Noise Immunity: Input filtering and opto‑isolation reduce transients

Package Contents

• 1771‑IA Discrete Input Module
• 1771‑WA Wiring Arm
• Installation instructions (printed)

Frequently Asked Questions (FAQ)

Q: Can I use this module with 240V AC?
A: No. The maximum AC operating voltage is 138V AC. Do not exceed this.

Q: What happens if the input current is lower than nominal?
A: The module may not detect the On‑state reliably. Verify your field device complies with the input current specification.

Q: Is the wiring arm reusable?
A: Yes. The 1771‑WA arm remains with the field wiring for fast replacement.

Q: Does this module support DC sinking or sourcing?
A: The 1771‑IA accepts DC voltage (97–138V DC) and does not require sourcing/sinking configuration.

Why Buy From Oiltech Controls?

• 15+ years of experience in industrial automation spares.
• Global shipping via FedEx, UPS, or DHL.
• Every unit is tested before shipment.
• Offering tested surplus and refurbished options.
• 12‑month warranty on all products.
• Technical verification for obsolete control systems.

Contact Information
For inquiries: info@oiltechcontrols.com
WhatsApp: +86 158 8020 0923

Shipping: We ship worldwide with FedEx, UPS, or DHL. Tracking number provided after dispatch.

Warranty & Support: 12‑month warranty from date of delivery. Technical support available before and after purchase.

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