1762‑IR4 | Allen Bradley | 4‑Channel RTD/Resistance Input Module

Allen‑Bradley 1762‑IR4 4‑Channel RTD/Resistance Input Module

The Allen‑Bradley 1762‑IR4 is a 4‑channel RTD/resistance input module for MicroLogix systems, executing precision temperature and resistance measurement with autocalibration, multi‑type RTD support, and configurable filtering. Cold engineering tone, ASCII‑only formatting, deterministic structure, and datasheet‑style compliance are applied.

Module Specifications

Measurement Accuracy

Accuracy at 25 °C (77 °F), Autocalibration Enabled

• RTD Inputs: ±0.2…±0.6 °C depending on RTD type
• Resistance Inputs: ±0.5…±1.5 Ω depending on resistance value

Accuracy at 0…55 °C (32…131 °F), Autocalibration Enabled

• RTD Inputs: ±0.4…±1.1 °C depending on RTD type
• Resistance Inputs: ±0.25…±2.5 Ω depending on resistance value

Repeatability

• Nickel / Nickel‑Iron RTDs: ±0.1 °C
• Other RTDs: ±0.2 °C
• 150 Ω resistance: ±0.04 Ω
• Other resistances: ±0.2 Ω

Performance Characteristics

• Channel Update Time: 6…303 ms per enabled channel (filter‑dependent)
• Common Mode Noise Rejection:
  • 110 dB min @ 50 Hz (10 or 50 Hz filter)
  • 110 dB min @ 60 Hz (10 or 60 Hz filter)
• Normal Mode Noise Rejection:
  • 70 dB min @ 50 Hz (10 or 50 Hz filter)
  • 70 dB min @ 60 Hz (10 or 60 Hz filter)

Calibration Behavior

• Autocalibration occurs on channel enable and on configuration changes.
• Optional periodic calibration every five minutes.
• Ensures stable measurement drift control across temperature ranges.

Functional Characteristics

• Supports multiple RTD materials and resistance ranges for broad industrial temperature‑sensing applications.
• High input impedance prevents loading effects on low‑energy RTD circuits.
• Channel isolation prevents cross‑channel interference in multi‑sensor installations.
• Configurable filtering allows tuning for noise‑heavy or fast‑response environments.

Field Installation Notes

• Maintain shielded RTD wiring to reduce induced noise.
• Avoid routing sensor wiring near high‑current conductors.
• Ensure proper termination to avoid broken‑input diagnostics.
• Confirm MicroLogix power budget when combining multiple analog modules.
• Maintain non‑condensing humidity to protect terminal integrity.