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« on: May 20, 2009, 01:48:48 AM »
This is how the limits/home work for combined switches.
If you are doing a homing move the limits will be treated as home switches, Mach will move one axis at a time (if using Ref All to home) until a switch is seen and then back off until it closes again, home is set for that axis and Mach moves the next axis and repeats until all axis are homed.
When Not homing the switches are treated as Limit switches and if you touch them Mach will E-Stop. You can have Auto Limit Override enabled which will allow you to press the Reset button and then Jog back off of a limit switch, this will be at a reduced speed for the first press of the jog key, this is just in case you inadvertantly jog the wrong direction and gives you time to react.
Next is soft limits, they are from Config menu then Homing and limits. What they will do is stop the machine from ever hitting the physical limit switches and also when you press Start it will give you a warning if the code if going to take you outside of any softlimit.
To set the softlimits you set the X and Y Minimum and the Z Max as Zero, the X and Y Max are set to the length of travel on these axis and the Z Min is set likewise but using a negative number. You then have a slow zone and this is to allow Mach to slow down to a crawl so it can creep right up to the limit switch but not overshoot and hit it. The size of slow zone will depend on the Accel/Decel of your machine, if a fast Accel then the distance will be small, Slow Decel and it will have to be bigger, the only way to fnd this distance is through trial and error by jogging at full rapid towards a limit and see if the SoftLimits can stop the axis in time before the physical limit is tripped.
Hood