pnp sensors, pull down resistors, and NC limit switches with mesa 7i96s

PCW has a very valid point there. I've used normally closed limit switches, probe, e-stop buttons etc on my recent build for that very reason.

If a cable gets damaged or comes loose the machine stops.

As for the christmas tree effect I just see it as bonus

i keep getting a joint 0 limit switch error and i can't get the machine to jog. i realize that running it NO for the limits is what i want. i get an error on all the joints but the joint 0 is the one that i get everytime i hit one of the limits. i just wanted to make sure the lights on the mesa 7i96s are supposed to be on and then they turn off when the limit is reached? i'm making progress, slowly. i finally got the machine talking to the mesa board and the computer. i just keep getting those joint errors. i know its something simple im missing. back to reading the linuxcnc manuals.

i meant normally closed (NC). for the limits. i understand the limits now. NC, when you break contact the circuit opens and the light goes off. if i can just get the joint errors figured out.

For NC switches, you must invert the switch input in hal
(pncconf does this with a "Inv" checkbox next to the input)

To change it in an existing hal file you would change say:

hm2_7i96s.0.inm.00.input-05
to
hm2_7i96s.0.inm.00.input-05-not

(assuming input 5 was a limit switch)

your limits should be outside the travel envelope. They should never get hit. Use a home_offset to move off the home switch if it is a shared home/limit switch so it does not trigger a limit error after homing

A thing to note here is that the home_offset value needs to be positive or negative depending on which end of the axis that is used for homing.

It's very easy to miss and can cause crashes on homing if set incorrectly.