I'll think about it some more in my sleep.
Active LOW means that the LIMIT condition will be triggered when Mach sees a LOW (ground) on the input (i.e. the condition is ACTIVE when the signal goes LOW)
It baffles me how this is working now if ,as you say, you have NC switches. If this is ture then all the inputs are LOW already and that should be triggering all the limits. The lights would be on for them in the diagnostics screen.
Are you sure these are not NO switches. You can test this by pulling the wires off of one of the switches and use an ohmmeter across the connection on the switch from where the wires came. If you measure a short (0 ohms) then you are correct. If there is an open circuit (no meter reaction) then they are in fact NO.
Let me think on it. There is no need to use more than one input for all of the limits and even the home switches, freeing up a lot of inputs. What you do is wire them all in series.
From the BOB input to a switch, from that switch, to the next switch, from that switch to the next etc. etc and finally back to ground on the BOB. The switches have to be all N.C. so the signal can be activated by any one of the switches going open. The setting would be set for ACTIVE HIGH. (the SIGNAL is normally low and is ACTIVATED when it goes HIGH). The high comes from the pull up resistor when the line is no longer pulled low by the switch string.
Sage