6ES7231-5PD32-0XB0 is Siemens SIMATIC S7-1200 SM1231 RTD analog input module with 4 channels 16-bit resolution. It supports multiple RTD and resistance sensors for temperature measurement, designed to expand S7-1200 PLC digital control system.

6ES7461‑3AA00‑0AA0 is Siemens SIMATIC S7‑400 IM461‑3 receiver interface module, used for distributed remote rack expansion, max connection distance up to 102 m, supports P‑bus and K‑bus(C‑bus) transmission, must be paired with IM460‑3 sending module for S7‑400 multi‑rack distributed PLC system.