Hello hopefully someone can help,
I installed the SS on my machine hooked it up to Hobby CNC board, and machine everything works fine except for homing. I checked the switches to see if they work in mach and they do, they light up. Problem is that when I home  any axis the system hits the switch (the switch lights) but mach keeps on going ignoring the switch.  I have tried 1 axis at a time and it still does the same. This was working fine before I installed the SS board. I do have all the latest updates for the SS installed, and the latest mach 3 installed. I am running the machine on a windows 7 64 Bit computer, with 4 gigs of ram and a quad core CPU. Your help is greatly appreciated thanks again

Cant think what could be the problem there but if you attach your xml I will see if there is an issue with your config.
Hood

Thanks for your prompt reply,
I fixed the problem -- I had to go into the SS config and set the noise filtering for home at 20.0. Apparentlly there is to much noise with the limit switches.

I find this interesting, I'm having the same problem on a brigeport conversion and it does the same thing on my Z axis, 2 switches it runs past the home switch and ignors the limit switch and finally the travel ends and the motor stalls, not a pleasant experiance at all.

It doesn't do this every time just once in a month or so, to often.

Another person on the forum suggested that I use the second switch (limit switch) and use it to disable the drive instead of using it as a limit and add a momentary contact switch so I can re-enable the drive to jog off the homing limit. 

I didn't know there was a noise filter for homing can you tell me were it is please so I can try it out on my machine.

Thank you,
Ted

cyberhawkv

Usually with noise you will get the switch being seen falsly, ie it will see a false trigger before the switch is actually seen. Cant really see how noise could cause the switch to not be seen but if its working then suppose thats all that matters. I would however be careful with the amount you have as 20 is quite high for the SS filtering and you may well be getting a delay before it is seen.

sqweeker

The reason it is going past the limits is Mach ignores home switches when homing so if your home is not seen for some reason the limits will be ignored even if they are seen. This was made that way as most used the same switches for limits and home as the parallel port had limited inputs. Now with external devices inputs are much more in numbers so often people have seperate home switches (like your Z) sadly there is no way to make the Limits active when homing, hopefully Rev4 of Mach will address this issue.

The filtering is from Plugin Control menu the SS Config, as mentioned above dont put it too high, try 1.43 and step up in these increments until it solves the problem if it does but dont go too high or you will get a huge delay.

Personally I cant see how it will help unless there are issues with the plugin as previously mentioned noise should cause an early trigger rather than none at all.
Hood

Thanks  for the info, this is very helpful.

Hello Hood thank you for the reply,
I don't think I explained the problem very well.

When doing homing or tool changes the z axis does stop on the home switch, during tool changes it also rises up to the home switch and stops.

When you hit the stop button during a program run the Z moves very rapidly up to the home position (safe Z setting) and over shoots the switch them goes right past the limit and jams the ball screw.

Your explaination of Mach not recognizing the limit maybe my problem and I may have to change the safe Z setting.

Thanks again,
Ted

I think the SS's soft limits work a bit differently from the parallel ports soft limits but been a while since I have messed with them. Try setting a larger slow zone in Homing and limits page and see if that helps.
Also you may or may not want the X to raise on Stop,  prefer it not to, if you dont want it to do that you can disable on the Safe Z page, I prefer to use machine coords for safe Z and just set that accordingly, that way I know it will always go to a set position, mine is -2mm so it is just 2mm before the axis extent. I however have servos with fast acceleration/decelleration so I can be close, if your acceleration/decelleration is slower you may need to set a larger amount.
Hood

Thanks Hood,
I'm going to change the safe Z and see if that helps, It's intersting that during the homing operation the Z runs at the speed set in motor tuning,... If I change the speed setting the Quill moves with the new settings.

But when it runs up from a stop command to safe Z it seems to run up at the fastest speed it can, do you know if the speed is setable for this or is it something in mach that is overriding the motor tuning settings.

Either way If I set safe Z to just above my work coordinates I should be in better shape I'm hoping.

Have a great weekend,
Ted

For homing the axis should run at the % of Max velocity that you have set in Homing and limits. For example if your motor tuning had a Velocity of 500 for the Z and the Homing Speed % in Homing and limits was set to 50% then the homing speed would be 250 units per min.

Safe Z will travel at full  rapid speed (Velocity that you have set in Motor tuning)

Personally I prefer to have the safe Z set in Machine Coords as then I know exactly where it will go to, if in work coords then it will be different every time with different code. Suppose most of the time that would be ok as it would move above your work but if for example you had safe Z set to 10mm in work coords and you pressed Go To Zeros it may smash into a clamp or something if that was higher than 10mm.

Hood