Hi,
o am I correct in assuming that X +++ and X--- can be wired in series and use the same input pin on the C10 ?? (Same for y & Z of course) but then again if all 5 switched are wired in series and are set normally closed, then any one of the switches being triggered will cause a stop ??
Yes, that is correct. In the early days of Mach when everyone used a parallel port with so few inputs it was the norm to connect limit switches
in series. You could also nominate three of the limits, one for each axis as home switches. The problem becomes that Mach has to interpret what any
given switch event means, was it intended as a home event or is it a limit for which an immediate Estop is in order?.
With an ESS and two breakout boards you have plenty of inputs and do not have to compromise. You have sufficient inputs to have three separate inputs
for three individual home switches and six inputs for six limit switches. This would mean for instance you can use proximity switches as limits and not
have to try to wire them in series/parallel on some other tricky combination and still have microswitches for home switches. No tricky interpretation by Mach
required.
Home switches can be anywhere on an axis, even in the middle. It is normal to place them at one end of each axis however but they don't have to be right at the
absolute end. My home switches are within 3mm short of each axis end with limit switches just beyond them.
You might ask 'what is the sense of having machine 0,0,0 somewhere inside the travel envelope', but that is what 'home offsets are all about.
Thus if your X axis home switch is 10mm from the negative limit then you would nominate the X axis home offset as 10mm. Thus when the
X axis homed its machine coordinate would not be set to zero but rather to 10mm. When the X axis is homed it is 10mm away from the negative
limit and with the home offset, hey presto, the machine coordinate is 10mm as well.
Craig