Product Summary
The 1746-NR8 is an Allen-Bradley SLC 500 RTD and resistance analog input module. This module accepts signals from eight separate RTD sensors. It also measures direct resistance from various devices. Engineers use it for precise temperature monitoring and control. The module consumes just 1.82W maximum from the backplane.
Expert Technical Evaluation & Performance Review
Signal Processing and Conversion Accuracy
The 1746-NR8 uses sigma-delta modulation for its analog-to-digital conversion. This method delivers high-resolution measurement with a precision of 0.01°C. The module performs an auto-calibration process at every power-up. You can also program it to recalibrate every five minutes. This ensures your readings remain stable and accurate over time.
Input Filtering and Step Response
This module includes a low-pass digital filter for noise rejection. It also features programmable input filters for flexible setup. The input step response takes 60 milliseconds to settle. The output step response completes in just 2.5 milliseconds. This allows the module to track fast-changing process conditions effectively.
Environmental and Electrical Tolerances
The 1746-NR8 operates reliably in temperatures from 32 to 140°F. It can survive storage temperatures from -40 to 185°F. The module handles non-condensing humidity levels between 5 and 95%. Its maximum common mode voltage is ±1 Volt. The permanent overload limits are ±5 mA for current and ±5 VDC for voltage. Isolation between inputs and the backplane is rated at 500V AC for one minute.
Sensor Compatibility and Wiring Guide
This module supports 2-wire, 3-wire, and 4-wire RTD configurations. For 2-wire setups, use Belden 9501 shielded cable or an equivalent. For 3-wire or 4-wire sensors, use Belden 9533 or Belden 83503 cable. Long 2-wire cable runs reduce measurement accuracy significantly. If you cannot avoid long runs, use a lower gauge cable like AWG 16. The removable terminal block accepts only single wire connections per terminal.
Channel Update and Resistance Ranges
The update time for all eight channels ranges from 6 milliseconds to 2 seconds. This depends on your filter and sensor configuration. The module accepts direct resistance inputs in several ranges. These include 0 to 150 Ohms, 0 to 500 Ohms, and 0 to 1000 Ohms. It also supports a 0 to 3000 Ohm range for high-resistance applications.
Logistics & Standard Packaging Details
- One (1) Allen-Bradley 1746-NR8 RTD/Resistance Input Module
- One (1) compatible Allen-Bradley 1746-RT-35 Removable Terminal Block
- The module is securely packaged in an anti-static protective bag
- Product labeling includes the catalog number, UPC, and serial information
- We offer express delivery shipping via FedEx, UPS, and DHL
