Schneider electric zelio extendable modular plcs schneider electric sr3b261b this modular smart relay from the zelio logic series has 16x discrete inputs 10x relay outputs and a supply voltage of 24v ac the compact unit is designed for simple control systems and can have its functionality extended by the addition of separate io modules the units also comes with an internal clock and display the module can be din rail mounted and also has retractable lugs that enable screw fixing mountin