Siemens digital expansion module. The siemens digital expansion module with 8 output channels is a highly efficient device used with simatic et 200s plcs. It has various advanced features like diagnostics indication leds, short circuit protection, reverse voltage protection, and potential isolation between the channels and the backplane bus. Hence, it is an ideal expansion module for various applications. Features and benefits. Connect to terminal modules tm-e with automatic encryption. Module exchange during operation subject to voltage (hot swapping). Input supply rating of 24Vdc.