6ES7 312-5BD01-0AB0 Siemens S7-300, CPU 312C COMPACT CPU WITH MPI. Simatic s7-300, cpu 312c compact cpu with mpi, 10 di/6 do, 2 fast counters (10 khz), integrated 24v dc power supply, 16 kb working memory, front connector (1 x 40pin) and micro memory card required.