ControlLogix 1756-IR6I RTD Input Module Overview

The ControlLogix 1756-IR6I is a versatile and high-precision 6-point isolated RTD input module designed for accurate temperature measurements in industrial applications. It supports various RTD sensors and offers excellent noise rejection and calibration accuracy.

Signal and User Counts

• 1…487 Ω:
  • Low Signal: 0.859068653 Ω (-32768 counts)
  • High Signal: 507.862 Ω (32767 counts)
• 2…1000 Ω:
  • Low Signal: 2 Ω (-32768 counts)
  • High Signal: 1016.502 Ω (32767 counts)
• 4…2000 Ω:
  • Low Signal: 4 Ω (-32768 counts)
  • High Signal: 2033.780 Ω (32767 counts)
• 8…4020 Ω:
  • Low Signal: 8 Ω (-32768 counts)
  • High Signal: 4068.392 Ω (32767 counts)

Technical Specifications

• Inputs: 6 individually isolated RTD
• Input Range:
  • 1…487 Ω
  • 2…1000 Ω
  • 4…2000 Ω
  • 8…4020 Ω
• Resolution:
  • 1…487 Ω: 7.7 mΩ/bit
  • 2…1000 Ω: 15 mΩ/bit
  • 4…2000 Ω: 30 mΩ/bit
  • 8…4020 Ω: 60 mΩ/bit
• Sensors Supported:
  • 100, 200, 500, 1000 Ω Platinum (alpha=385, 3916)
  • 120 Ω Nickel (alpha=672, 618)
  • 10 Ω Copper
• Current Draw:
  • @ 5.1V: 250 mA
  • @ 24V: 125 mA
• Total Backplane Power: 4.25 W
• Power Dissipation, Max: 4.3 W
• Thermal Dissipation: 14.66 BTU/hr
• Open Circuit Detection Time: Negative full scale reading within 5 s (positive full scale if terminal A is lost alone)
• Overvoltage Protection, Max: 24V AC/DC
• Noise Rejection:
  • Normal Mode: 60 dB at 60 Hz
  • Common Mode: 120 dB @ 60 Hz, 100 dB @ 50 Hz
• Channel Bandwidth: 15 Hz
• Settling Time: <80 ms to 5% of full scale
• Calibrated Accuracy @ 25 °C: Better than 0.1% of range
• Calibration Interval: 6 months
• Offset Drift: 10 MΩ/°C
• Gain Drift with Temperature:
  • Nominal: 50 ppm/°C
  • Max: 90 ppm/°C
• Module Error: 0.54% of range
• Module Scan Time:
  • 25 ms min floating point (ohms)
  • 50 ms min floating point (temperature)
  • 10 ms min integer (ohms)
• Data Format: Integer mode (left justified, 2s complement), IEEE 32-bit floating point
• Module Conversion Method: Sigma-Delta
• Isolation Voltage: 250V (continuous), basic insulation type, input channels-to-backplane, and input channel-to-channel
• Module Keying: Electronic, software configurable
• Removable Terminal Block: 1756-TBNH, 1756-TBSH
• RTB Keying: User-defined mechanical
• Slot Width: 1
• Wire Category: 2
• Enclosure Type: None (open-style)

Environmental Specifications

• Operating Temperature: 0…60 °C (32…140 °F)
• Storage Temperature: -40…85 °C (-40…185 °F)
• Relative Humidity: 5…95% non-condensing (IEC 60068-2-30, Test dB, Unpackaged Damp Heat)
• Vibration Resistance: 2 g @ 10…500 Hz (IEC 60068-2-6, Test Fc, Operating)
• Shock Resistance:
  • Operating: 30 g (IEC 60068-2-27, Test Ea, Unpackaged Shock)
  • Non-operating: 50 g (IEC 60068-2-27, Test Ea, Unpackaged Shock)
• Emissions: IEC 61000-6-4
• ESD Immunity: IEC 61000-4-2 (6 kV contact discharges, 8 kV air discharges)