The PLC programs in ladder logic with function block using EZ Ladder Lite software. Two models are available: Both the SI-100 and SI200 have four inputs and four outputs with four programmable LEDs. The SI-200 also has a four-digit numeric display, real-time clock, and two pushbuttons. An optional Quick Start kit includes the Solves-It!, programmable cable, screw-terminal socket, and the software.