Configured for precision analog signal acquisition in industrial automation frameworks, the Allen-Bradley 1746-NR8 1746NR8, also cataloged as the 1746-NR8 SLC 8 Point Resistance Input Module, provides direct physical and electrical execution for measuring multi-channel resistance and RTD inputs across controller chassis racks.

Part Number Breakdown & Model Matrix

Hardware Specifications

Backplane Bus & Network Communication Parameters

The hardware utilizes backplane bus communication velocity licences to maintain deterministic polling rates across analog input channels. I/O density scaling capabilities allow operators to expand measurement arrays across backplane slots without violating bus timing constraints or update intervals. Firmware flash compatibility ensures that low-level communication protocol stacks remain synchronized with controller processors during active process monitoring.

Package Contents & Ordering Info

• 1 x Allen-Bradley 1746-NR8 Resistance Input Module (Part Number: 1746NR8)
• 1 x Removable Terminal Block (RTB) Connector
• 1 x Technical Compliance Documentation Leaflet

Field Installation Guidelines

• Ensure chassis power is completely removed before inserting or extracting the input module from the backplane rack.
• Mount the module into any available I/O slot except Slot 0, ensuring proper alignment with backplane guide rails.
• Connect field signal wiring to the removable terminal block, maintaining proper shielding for low-level resistance measurements.
• Route analog sensor cables away from high-voltage power lines and variable frequency drives to minimize electromagnetic interference.

Frequently Asked Questions

• Q: What is the primary operational function of this module within the control system?
• A: It measures multi-channel resistance and RTD signals from field sensors and converts them into digital values for the controller.
• Q: Can this input module be installed in Slot 0 of the SLC 500 chassis?
• A: No, Slot 0 is reserved for the processor unit; this module can occupy any other available I/O slot.
• Q: What is the power consumption profile of the hardware?
• A: The unit consumes a maximum of 1.82 W, drawing 100 mA from the 5 VDC backplane and 55 mA from the 24 VDC supply.
• Q: What step response time is specified for the input channels?
• A: The module features a step response time of 60 milliseconds for inputs and 2.5 milliseconds for outputs.
• Q: What operational temperature range is supported by the device?
• A: The hardware functions reliably within an ambient operating temperature range of 0 deg C to +60 deg C.
• Q: Does this module support live insertion and removal (hot-swapping)?
• A: No, power to the chassis must be switched off prior to installing or removing the module from the backplane.
• Q: Why is proper shielding required for field wiring?
• A: Shielding prevents high-frequency electrical noise from corrupting sensitive resistance and temperature measurement signals.
• Q: What maintenance procedures are recommended for this unit?
• A: Periodically inspect terminal block connections for secure torque and ensure ventilation around the chassis remains clear.