home switch issues

hi all i am having troubles with my home sequence. z home works perfect everytime but x and y work when they want to. i keep getting a "home switch inactive befor backoff move" some times i have to run the home sequence several time to get it to actualy home correctly. i have a shared limit and home/limit switch wired in series normaly closed for each axis. my z axis uses a DPDT lever switch as the limit and home switches. the x and y axis use a normaly closed push button switch.

i think my problem is stemming from the switch themselves and not the configuration. none of the wireing on the machine is shielded except the leads that connect the machine to the controller box are shielded. when in limit mode and not in home sequence all switches function as advertized. when i get home i will post my configuartion files.

thanks for you help

first of all , it's extremely good practice to have all low voltage cables screened for a number of reasons , also depending on how you have the switches wired
using a pull up resistor to 5v so that the switches have a voltage on them rather than a floating ground , this of course depends on the controller interface your using
it could also be the type of push button switch your using too , micro switches tend to work best , some push switches have a long travel before they break contact , so
Lcnc thinks it's still an active switch .

I doubt it will be software related , it looks more related to mechanical or Noise , again having pullups to 5v etc , helps in these cases .

in any case post your files and we can eliminate that possibility hopefully

i do have pull up resisters on my limit switches. i have found that if i run each home sequence individually from the machine drop down i tend to have fewer problems.

here are my configuration files

[AXIS_0] x axis

TYPE = LINEAR
HOME = 0.0

MAX_VELOCITY = 3

MAX_ACCELERATION = 40

STEPGEN_MAXACCEL = 68.75

SCALE = 4000.0

FERROR = 0.05

MIN_FERROR = 0.01

MIN_LIMIT = -1.0
MAX_LIMIT = 24.5.0

HOME_OFFSET = -0.4000000

HOME_SEARCH_VEL = -0.050000

HOME_LATCH_VEL = -0.050000

HOME_IGNORE_LIMITS = YES

HOME_SEQUENCE = 1



[AXIS_1] y axis

TYPE = LINEAR
HOME = 0.0

MAX_VELOCITY = 3

MAX_ACCELERATION = 40.0

STEPGEN_MAXACCEL = 68.75

SCALE = -4000.0

FERROR = 0.05

MIN_FERROR = 0.01

MIN_LIMIT = -0.5

MAX_LIMIT = 12.5

HOME_OFFSET = -0.250000

HOME_SEARCH_VEL = -0.050000

HOME_LATCH_VEL = -0.050000

HOME_IGNORE_LIMITS = YES

HOME_SEQUENCE = 2



[AXIS_2] z axis

TYPE = LINEAR
HOME = 0.0

MAX_VELOCITY = 1.3300002128

MAX_ACCELERATION = 25.0

STEPGEN_MAXACCEL = 31.25

SCALE = 13600.0

FERROR = 0.05

MIN_FERROR = 0.01

MIN_LIMIT = -1.0

MAX_LIMIT = 0.01

HOME_OFFSET = 0.125000

HOME_SEARCH_VEL = 0.050000

HOME_LATCH_VEL = 0.036765

HOME_IGNORE_LIMITS = YES

HOME_SEQUENCE = 0

thank you for your help

I had the same issues, and when using HALscope, I found I was getting interference even though I used shielded cables to each switch. I really had to look hard to find it, but the system see's these micro pulses as a switch trip and causes the errors you are seeing. I was told to put a filter capicitor across my inputs, and that it should fix my issue. I am just getting my machine set back up after a move over the summer, and will be able to test this fix soon.

Regards,

Will

Ok Andy, I will give it a shot. I was originally told that I couldn't just debounce realtime dependent signals, which is why I looked into filtering the signal wires with a capacitor.

Thanks,

Will