Allen-Bradley 1790D-N4C0: High-Precision Analog Input Module

Monitor process variables with excellent accuracy. The Allen-Bradley 1790D-N4C0 is a four-channel analog input module. It reads standard 4-20 mA or 0-20 mA current signals from sensors like pressure transmitters and flow meters. This module delivers reliable data to your DeviceNet control system for precise monitoring and control.

Key Features & Measurement Advantages

• High Accuracy Sensing: Provides 0.2% full-scale accuracy for trustworthy process data.
• Flexible Signal Ranges: Software-selectable for either 4-20 mA or 0-20 mA input signals.
• Fine Resolution: 12-bit conversion delivers detailed measurement (1 part in 4096).
• Fast Data Update: Scans all four channels quickly with a 10 ms conversion time per channel.

Detailed Technical Specifications

• Product Model: Allen-Bradley 1790D-N4C0 (1790D Series Compact I/O).
• Input Channels: 4 single-ended, non-isolated current input channels.
• Signal Ranges: Software configurable for 4-20 mA (default) or 0-20 mA.
• Resolution: 12-bit (unipolar), 3.90 µA per bit for 4-20 mA range.
• Accuracy: ±0.2% of full scale across 0 to 55°C operating temperature.
• Conversion Speed: 10 milliseconds per channel for stable readings.
• Input Impedance: Low 249 Ω burden to minimize voltage drop on loop-powered sensors.
• Power Supply: Requires 24V DC field power (21.6-26.4V) and DeviceNet bus power.

Installation & System Integration

• Wiring Connection: All channels connect via a single 37-pin D-sub connector.
• Visual Indicators: Four bi-color (red/green) LEDs show status for each input channel.
• Expansion Capacity: This base module can support up to two additional discrete I/O expansion modules.
• Calibration: Factory calibrated; no user calibration is required, saving maintenance time.
• Isolation: 1250V AC RMS optical isolation between analog inputs and internal logic.

Packaging & Support Details

• Package includes one 1790D-N4C0 analog input module.
• This precision module is covered by a standard 12-month warranty.
• We ship worldwide using reliable carriers like FedEx, UPS, and DHL.

Expert FAQs

• What types of sensors are typically connected to this module?
  It's ideal for any 2-wire 4-20 mA loop-powered transmitter: pressure transducers, temperature transmitters (with transmitter), level sensors, and analog flow meters.
• How do I connect a 2-wire loop-powered transmitter?
  Connect the transmitter's positive (+) wire to your 24V DC supply positive. Connect the transmitter's negative (-) wire to the module's input channel terminal. Connect the module's common for that channel back to the 24V DC supply negative.
• What does "single-ended, non-isolated" input mean?
  "Single-ended" means all four channels share a common reference point. "Non-isolated" means the input circuits are not electrically isolated from each other. This is cost-effective but means all sensors should share the same ground reference to avoid noise.
• Why is low input impedance (249 Ω) important?
  A low burden resistance minimizes the voltage drop across the input. This leaves more voltage available for the loop-powered transmitter to operate correctly, especially over long wire runs.
• Can I mix different current ranges on the four channels?No. The range (4-20mA or 0-20mA) is set globally via software for all four channels simultaneously. All channels on one module must use the same input range setting.

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