Joint limit switch errors

Suddenly the CNC machine is showing joint limit errors on startup and I cannot clear them. The machine is a gantry has been working fine until this came up.
I have used a meter to check the wiring and checked for the continuity of the wiring and that the limit switches showed a closed contact.
Halmeter also shows True on Parports11, 12, and 13 which are the ports for the X, Y, and Z axes.
I will attach a screen shot showing the Axis interface so you will see the system software load and the error messages. I will also attach the .hal and .ini files that were just created this morning.


I will appreciate any suggestions

Can you try the switches manually while watching the hal pins?
The way they are connected in hal, they should be be low until you hit home/limit

seams one is broken
i had that also and the mashine tryed to home in wrong direction

Thank you for your response.
I tried that on two of the axes and was more puzzled. When I tried that, the True did not change to False as I thought it should. I thought that maybe it was not reactive under those circumstances and that was why it did not change.
Does that give you a clue?

Thanks for your response, I checked the limit witches with a meter and they showed closed as they normally should be and then blocked each one activated and they showed open. I did that same tests and measured at the breakout box on the serial link. I also tested the same way on the RS-232 plug that connects to the computer. And also tested with the Halmeter. I was only puzzled by the Halmeter which did not show that open when the limit switches contacts opened.

If you use halmeter or the watch option in axis ( NOT show )
and the parallel port pins do not change when you activate the limit switches,
This suggest that you have a hardware problem like bad BOB, broken wire
bad parallel port, etc etc

Thank you for your reply. I was puzzled by too much information. I have a back up computer and tried it and it also showed the same problem.I thought maybe there might be a broken wire but completely rewired the limit switches and thought that was all working. But the only common thing would seem to be the BOB which you mention. i will try to get a replacement for that.

Thanks again.

norbertfarquharsh wrote: Thank you for your reply. I was puzzled by too much information. I have a back up computer and tried it and it also showed the same problem.I thought maybe there might be a broken wire but completely rewired the limit switches and thought that was all working. But the only common thing would seem to be the BOB which you mention. i will try to get a replacement for that.

Thanks again.

What bob are you using as if it is one of the cheap China one with the blue relay on it. The need 12-24V for the input pins to work

Thank you for your comments.

The BOB I am using is from Xylotex and has been in use for maybe 4 years, but I do not remember exactly.. It has no relays on it. I have already ordered a new one from Xylotex and will see what happens then. Just cannot figure the logic of the system to see how the errors occur.

You should check if the Bob is getting supply voltage as some will not work without it.
Some bobs have jumpers for setting them as pullup or pulldown.