6ES7138-4CA01-0AA0 PLC I/O Module for use with ET200S Series 81 x 15 x 52 mm Current, Potential, Voltage 24 V dc. The Siemens power module is designed to use with ET 200S PLCs. It has various advanced features like reverse polarity protection, extensive diagnostics with indicators, galvanic isolation between rated load voltage and the backplane bus and also between the power modules that make it an ideal module for various applications.