The home signals and signals from limit sensors can connect to an OpenCNC through the H/L switch that consists of PNP/NPN transistors on the remote IO board (RIO). In addition, users need to setup Home Limit parameters and select ‘Enable’ on the parameter setting interface (shown below), so that the actual home signals and signals from limit sensors can connect to the RIO. Based on the selected axis from the Home Limit parameter setting (indicated in the red box above), each axis consists of 3 DI units and starts off with X256 in the fixed order of: positive limit, negative limit and home signals.