SIMATIC S7-1200, analog input, SM 1231, 4 AI, +/-10V, +/-5V, +/-2.5V, or 0-20mA/4-20mA, 12 bit+sign (13 bit ADC) SIMATIC S7-1200 Basic Controller - flexible thanks to a wide range of communication options. With signal modules, you can adapt the configuration of your SIMATIC S7-1200 (except CPU 1211C) to suit your individual requirements. A range of digital and analog input, output and mixed modules is available for this purpose, including fail-safe versions. This fine-grained design option saves you space in the control cabinet and optimizes your hardware costs.