I am sure I do not understand how to use the inputs and outputs

[hswaters]

I have a plasma table I am building;  I have put limit switches on both ends of each axes.  For simplicity I wired them all in series as normally closed.  So if any switch is opened I get a low signal on input 10 which stops everything.   Input 10 is on a pmdx416. I am not sure if this is the right way to set it up or not.  I found in the configuration a bucket full of inputs listed in way greater numbers than exist on the smartbob.  When I was working I used control software to condfigure controls for petrochemical applications.  In that software you simply refereed to the input number and you could assign it to any control action you wanted to.  I suspect mach4 must be like this but I am not sure how to implement it.  I hipe my wording of the question is not as confusing for you as it is for me.

[12strings]

Mach4 assigns limit switches to "motors".  So, presuming you have motor0 and motor1 mapped to your X and Y axis, and your limit switches are for these two motors, here is how to tell Mach4 about them:

First off - pin 10 is normally reserved for EStop functions.  And on the PMDX-416 the screw terminals are specifically labeled as such.  So I would choose a different input signal for your limit switches. (hitting a limit is NOT the same as EStop, even though both will halt the machine).  Perhaps "Pin 11".

Since your switches are normally closed, they should be wired between the PMDX-416 input terminal and the "ISO GND" terminal.  This makes the normal, "everything is OK" condition zero volts into the PMDX-416.  When any switch opens the PMDX-416 will see a logic high due to its built-in pull-ups.  This makes your limit switches "active high".

Go to the "Configure" menu and select "Mach...".  Click on the "Input Signals" tab.  Scroll down until you see "Motor 0 ++".  This is the motor0 positive limit switch input.  "Motor 0 --" is the motor0 negative limit switch input.  So... click the red "X" in the "Mapping Enabled" column for Motor0 ++, Motor0 --, Motor1++ and Motor1 --.  Then for each of these, click in the "Device" column and select the SmartBOB.  Then click in the "Input Name" column and select the PMDx-416 input signal name that corresponds to the input terminal you are using (i.e. "Pin 11" based on my suggestion above).  Leave the red "X" in the "Active Low" column, since your limit switches are active high.  Click on "OK".

You should now have all four Mach4 limit switch input mapped to that single input pin.

[hswaters]

What you say makes perfect sense and as they say "I can see perfectly now" how to handle this thing.  I will move off the estop and use some other pins for the limit switches.  Thank you very much for your help.