Technical Specifications

Parameter Specification
Model NFAI835-S51
Compatible System ProSafe-RS Safety Instrumented System
Input Signal Voltage: ±20 mV to ±1000 mV (range selectable)
Thermocouple: B, R, S, K, E, J, T, N, W5Re/W26Re, PLII, U, L
Number of Channels 8
Input Impedance 10 MΩ or higher
Burnout Bias Current Approx. 50 nA (for open wire detection)
Accuracy Voltage: ±(0.03% of reading + 2.5 μV)
Thermocouple: ±0.1% of span or ±1.0°C, whichever is larger (with CJC)
Resolution 1/200,000 (effectively 19-bit)
Conversion Speed 1 second per module (all 8 channels)
Common Mode Voltage 500 V AC (50/60 Hz) for 1 minute
Isolation Channel-to-Channel: Non-isolated
Channel-to-System: Optically isolated
Cold Junction Compensation (CJC) Accuracy ±1.0°C
Internal Power Consumption 0.55 W (Typical)
LED Indicators RUN/ERR (Run/Error), MODE, ALM, CH STATUS (per channel)
Key Diagnostics Open thermocouple (burnout), sensor short, over-range/under-range, CJC error, Module self-diagnosis
Hot Swapping Supported
Operating Temperature -20 to 70 °C
Mounting FCS (Field Control Station)
Safety Certification SIL 2 / SIL 3 (IEC 61508)
Hazardous Area Certifications FM, CSA, ATEX, IECEx, NEPSI