Paul Shaw,
What controller software are you using? I can’t get my limit switches configured. It’s frustrating. I think they were working on Mach 3, but they are giving me fits on Mach 4. My estop only allows the outputs to run if it’s depressed. I have to use it in reverse, and changing from active low to active high doesn’t help.
linux cnc
I haven’t used mach3 (or 4 ever) more than the demo. I did a lot of reading and ended up joining the uccnc crowd. It’s similar.
On my e stop there are two sets of terminals, one that uses it as normally open, and one that uses it as normally closed. Same goes for end stops, I’m sure you know that. Depending on how they are set, (NO, or NC) they need to be wired accordingly. Have you looked at some wiring diagrams?
Active low to active high in this situation wouldn’t change the direction the e stop would work. That just reverses polarity (I think)
@Mark_Leino My mistake. It is Mach 4. I felt the same way, Mark, when I first saw that (active low/active high) after having only used TinyG, Grbl and Marlin firmware. Each time I switch to a different controller system, it’s almost like I’m going back to square one. You are right regarding reversing polarity. Because, I think, that rather than just breaking the entire circuit, which would turn the whole system off (thus not allowing further signals being sent to the system) they use active low versus active high (current) to determine the state of the machine- active high- meaning that when the switch is hit it forces the current to go higher than it would be in normal operation state, the signal tells the system that the switch has been activated, and to do whatever the program tells the system to do in that active state. I may be “off-base,” but that is my general assumption.
@Mark_Leino That could be the problem with my estop, as it is called by them a (SPDT) switch - single pole double throw - switch and I may not have them wired correctly. I’m not sure about the limit switches, though; as they are NPN, normally closed, inductive sensors. I had them working okay on Mach 3, but I was encouraged to purchase the Mach 4 license, and since changing the version, I have a different profile generated, I may have made a configuration error somewhere. It has been a bit of a complicated process. With my limit switches, I will have to go back and take a step by step process to see if I (checked/clicked) an item I shouldn’t have or vice versa.
I use tinyg but don’t have limit switches other than z probe for doing pcbs.