Configured for precision temperature measurement in 1771 chassis systems, the Allen-Bradley 1771-IR (1771IR RTD Input Module) provides direct physical/electrical execution.

Hardware Revision & Series Matrix

• 1771-IR: Base catalog number specifying the 6-channel 3-wire RTD analog input module for PLC-5 systems.
• 1771-IR/A to 1771-IR/D: Revision level designations (Series A through D) reflecting incremental hardware layout updates while maintaining terminal pinout backward compatibility.

Technical Parameters & Operational Limits

Architecture & Backplane Bus Integration

The assembly processes resistance temperature detector signals across 6 dedicated channels, transferring digitized temperature data via backplane bus communication velocity routines to the processor. High channel-to-backplane isolation prevents field noise coupling into internal logic circuits. The module design maintains firmware flash compatibility across host PLC-5 racks to optimize I/O density scaling without inducing backplane buffer overruns during cyclic scan executions.

Package Component Checklist

• 1 x 1771-IR RTD Input Module
• 1 x Field Wiring Arm Alignment Keying Clip

Mechanical Installation & Wiring Guidelines

Chassis Insertion Steps

• Insert plastic keying bands into the chassis backplane connector at designated pin locations to enforce slot alignment.
• Align top and bottom circuit board edges with chassis card guides, pushing firmly until the rear connector latches into the backplane.

Cable Routing and Shielding

• Wire 3-wire RTD sensors using individually shielded, twisted-triad copper conductors.
• Connect the shield drain wire to frame ground at a single chassis terminal to eliminate ground loop current paths.
• Maintain at least 30 cm clearance between RTD signal cables and high-voltage AC power distribution wiring.

Technical Operational FAQs

• What sensor type connects to the 1771-IR module?

  The module interfaces directly with 6 independent 3-wire resistance temperature detectors (RTDs) for thermal measurement.

• What current does the 1771-IR draw from the chassis backplane?

  The internal logic circuitry draws a continuous current load of 0.950 A at 5 VDC from the 1771 backplane bus supply.

• Is hot-swapping allowed for this module during rack operation?

  No. System power to the 1771 chassis must be fully turned off before inserting or removing the card to protect backplane pins.

• What is the typical DC signal turn-off delay for the input channels?

  The module exhibits a typical DC signal delay (off time) of 50 ms across its input filtering circuitry.

• How are lead resistance variances balanced across 3-wire RTD inputs?

  The 3-wire input configuration automatically cancels equal lead wire resistances across the sensor connections to preserve accuracy.

• What wire gauge size is compatible with the field wiring arm?

  The field wiring arm terminals accept solid or stranded copper wire sizes ranging from 14 AWG to 22 AWG.

• What is the total power dissipation rating of the module?

  The module dissipates up to 4.75 W of electrical power during normal continuous operation within a 1771 chassis.

• Do spare designations like 1771-IR/A or 1771-IR/B replace the base unit?

  Yes. Series designations A, B, C, and D represent compatible hardware revision levels for the base 1771-IR catalog module.