SIMATIC S7-1500 Compact CPU CPU 1511C-1 PN, central processing unit with work memory 175 KB for program and 1 MB for data, 16 digital inputs, 16 digital outputs, 5 analog inputs, 2 analog outputs, 6 high-speed counters, 4 high-speed counters for PTO/PWM/frequency output 1st interface: PROFINET IRT with 2-port switch, 60 ns bit performance, incl. push-in front connector