[miwaba]

I'm really stuck with this limit switch problem. I have a dm2800 converted over to mach 3. I set limit switches by moving axis until limit switch was activated backed it off where it wasn't activated and set my zero on all axis this way.When I move off all axis and then reference all they go pass a little and then to zero no problem. Then I load a program and run the first tool. All axis go back to zero no problem. When I go to run the next tool the y axis activates the limit switch. I've tried to keep the axis off of zero by putting -.05 in the Z axis and .05 in the X and Y axis but it will still activate the switch. It was doing it on z axis for awhile and now on y. I put a G49 at the end of the program in the same line as the G91 G28 Z0 line. When the machine reads the M6 line and I change the tool for tool 2 and push cycle start it jumps back up to the G91 G28 Z0 line and activates the Y limit switch. I'm really lost on this can anybody help.

[2ferrous]

Sounds like something in your code...

Can you post your program?

Timothy

[miwaba]

TimothyThanks for the reply. I got it straightened out. I put a G90 at the end of each tool. The thing I didn't understand was there is a G90 on the line with the workshift that should of taken care of canceling out the G91. I guess these machines all work the same but are all a little different in some ways. Thanks againMike

[2ferrous]

Why are you switching between G90 and G91 within the program?
Usually the G91 is used for a sub routines to save coding space and time.
But with today's CAM there should be no need for it.

I never use G28 either....

[miwaba]

You're using a g91 for a sub program? G91 is incremental positioning. I would use a m98 for a sub program. All the machines that I know of use a g91 g28 z0 and g28 x0 y0 for homing except maybe some older matsuuras that I think use a g53