- SIMATIC S7-1200 Basic Controller - Digital I/O SM 1223, 16 DI/16 DO - 16 DI 24 V DC, Sink/Source - 16 DO, transistor 0.5 A - Flexible communication options - Signal modules allow inpidual configuration - Range of digital and analog input/output modules - Fail-safe versions available - Saves space in control cabinet - Maximizes hardware expenditure