SIPLUS S7-1200 SM 1221 16DI, with conformal coating based on 6ES7221-1BH32-0XB0 . 16 DI, 24 V DC, Sink/Source SIMATIC S7-1200 Basic Controller - Flexible thanks to wide variety of communication options With signal modules you can adapt the configuration of your SIMATIC S7-1200 (except for CPU 1211C) individually to meet your requirements. For this purpose, a series of digital and analog input, output and hybrid modules is available, including fail-safe versions. Thanks to this detailed expansion option you can save space in the control cabinet and get the most from your hardware expenditure. Just like the CPU, the digital input modules are also protected against extreme ambient conditions. Due to the 100% conformal coating they can withstand biologically, chemically and physically active substances, condensation, frost, and corrosive gases. Regardless of the conditions, your digital signals are reliably recorded.