Siemens 6ES7331-7PF01-0AB0 Analog Input Module The SIMATIC S7-300 SM 331 is an isolated, eight-channel analog input module for resistance and RTD measurement. It supports specified Pt and Ni sensors with 2-, 3- or 4-wire connections. Product phase-out announced by Siemens Product Overview Product family SIMATIC S7-300 / SM 331 Measurement Resistance and RTD sensors Order number 6ES7331-7PF01-0AB0 Technical Specifications Order number 6ES7331-7PF01-0AB0 Module type Isolated