Siemens 6ES7331-7SF00-0AB0 SIMATIC S7-300 SM 331 8xAI TC/4xAI RTD Ex Hazardous Area PLC I/O Module

The Siemens 6ES7331-7SF00-0AB0 is a SIMATIC S7-300 SM 331 analog input module with 8 isolated inputs for thermocouples or 4 for Pt100/Ni100 resistance thermometers, built to bring temperature signals from a hazardous area into the control system. It resolves up to 16 bit including sign, is PTB tested under number Ex-96.D.2108X, and carries an ATEX II 3 G (2) GD marking.

Technical Specifications

Selection Notes

Ten thermocouple types (B through U) and three RTD types (Ni100/Pt100/Pt200) on one module cover most hazardous-area temperature-measurement points on a single line without mixing module variants. The parameterizable 2.5-100 ms integration time trades noise rejection against update rate per channel group, and the matching 10-400 Hz interference-frequency suppression setting should track local mains frequency (50 or 60 Hz) to reject line noise on long thermocouple runs. The 0.008% basic error limit on RTD channels only applies at 25 degC; the wider 0.04% operational limit is what to budget against over the full ambient range.