Home and limits connect to the Table I/O card (part of any of our plug-n-run systems). You can have 4 homes and unlimited limits (wired in series). One home (Z), is used for the "touch-off" sensor (IHS) in conjunction with a Floating Torch Holder. The DTHC does not control the Z directly. It sends signals to MACH that control Z. MACH has THC logic as part of it's core engine. Besides being integrated as part of the toolpath for THC moves, having a fully functional Z affords you a lot of flexibility on your machine. It's easy to switch over to other types of cutting (just load a different MACH Profile at startup), and you can even do mixed mode type operations (like plasma and scriber in the same job) SheetCAM has all of the auto-touch off moves, leadins/outs, kerf offset, pierce height, initial cut height, end of cut pause, etc.
The DTHC has been enhanced recently with a "Smart-Kut" feature that allows it to set it's own target height (Preset Torch Volts) by sampling the first few inches of a cut. It's an option on the screen controls. Coupled with the DCP-01 Digital Current Probe option you have precise control over plasma cutting.
If you need any further technical information then feel free to join my Yahoo Support Forum. Also it's not a bad idea to download the system user manuals from the Website. All of the information about switch connections and setting up MACH are in the manuals associated with each type controller. The front end electronics (PC interface) are the same on all of our systems including the DTHC. The DTHC Setup manual has a lot of information about the DTHC, DCP and how to connect to a plasma unit, and lots of general plasma cutting information and theory. While there is not a specific section on the Lincoln unit we can help you make the two internal connections you need for automated control.