1771-IL

Overview

The Allen-Bradley 1771-IL is an 8-channel isolated analog input module designed for precise voltage and current signal measurement in Rockwell automation systems.

Input Configuration

• Inputs per Module: 8 fully isolated differential

• Input Voltage Ranges: +1 to +5 V DC, 0 to 5 V DC, -5 to +5 V DC, -10 to +10 V DC

• Input Current Ranges: +4 to +20 mA, 0 to +20 mA, -20 to +20 mA

• Input Impedance: >10 MΩ (voltage), 250 Ω (current)

Measurement Performance

• Resolution: 16-bit binary

• Accuracy (Voltage): 0.01% typical, 0.05% max of full scale at 25°C

• Accuracy (Current): 0.06% typical, 0.1% max of full scale at 25°C

• Linearity: ±1 LSB

• Repeatability: ±1 LSB

• Normal Mode Rejection: >120 dB @ 60 Hz

• Common Mode Rejection: >120 dB @ 60 Hz, 1 KΩ source imbalance

Isolation and Protection

• Isolation Voltage: +1000 V peak, channel-to-channel and channel-to-ground for 1 s

• Overvoltage Protection: 140 V AC continuous (voltage mode); 8 V DC continuous (current mode)

• Open Circuit Detection: Upscale reading (voltage mode), zero reading (current mode)

Power and Installation

• Module Location: 1771 I/O rack – 1 slot

• Backplane Current Requirement: 1.0 A @ +5 V DC

• Power Dissipation: 6.5 W max

• Thermal Dissipation: 22.2 BTU/hr max

Calibration and Output Data

• Calibration: Auto-calibration (offset and gain) via programming terminal

• Verification Interval: Every 6 months recommended

• Data Output:

• Unipolar: 0000 to +4095₁₀

• Bipolar: -4095₁₀ to +4095₁₀

• Engineering Units: +9999 BCD / +32767 binary

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