Limit switches / on or off

I have had help from Inventables support to re-flash my Arduino because I could not home the machine, the Z axis went to the top and tried to go further, like the limit switch did not stop it, and then it would not finish homing, I have got the machine working again but have not tried homing yet, is hard limits on by default or does it have to be turned on, I don’t want to try homing again in case I have the same problem

Issue the command $$, in easel I think it is in the machine inspector area.

the value for
$21=1 hard limits is on
$21=0 hard limits is off

But that is not for homing, just for limit switches.

The homing cycle is $22

$22=1 homing is enabled
$22=0 Homing is disabled

Thank’s Erik, that is what I wanted, so if I enable homing it should be safe, do I also have to turn hard limits on,

1 Like

For a quick fix, you could just short across the z axis contacts twice during homing to fool it into thinking it hit the top. I had to do that when I crushed it into dust, before replacements arrived. The hex wrenches work perfectly…

1 Like

No, hard limits are not necessary just to home the machine.

1 Like

Velcro on your Z axis works great, never break another switch.

1 Like


1 Like

You want your home positions to be accurate and repeatable so need to have the home switches firmly attached where they can’t move.

Thank’s Robert, I tried that with the hex wrench but it did not work the Z carriage got to the top again and was grinding and trying to go further, so I am now back where I was before I re-flashed, the machine inspector is showing alarm so I can’t do anything, how do I get it out of alarm, do I have to re-flash again
I think my wiring on the limit switches must be wrong as two came loose at the pins on the Gshield and I may have soldered them back in the wrong order, I did intend to replace it with shielded wire later on but now might be a good time to do it, I have read on here to use 22AWG, will speaker wire do

You can use this to work out your homing switch difficulties and it doesn’t require machine movement.

Thank you Larry, I am using the Serial Monitor in the Arduino to send commands, but how do I change the ‘status report mask’ in Grbl I can’t find it, what do I open first to find it, I am not too good with the computer side of this so I am sorry for the silly questions

Why would the Z axis matter I lower it to the work piece every time before starting anyway. Am I missing something.

When you bring up the serial monitor with the Arduino connected you should see the version number of grbl in the display of the serial monitor.

At that point you can issue a command to see the grbl parameters. In the “Send” line of the monitor type $$ and grbl will respond with the parameters that it current has.

To change the status report mask you would enter the command $10=19 as per the other thread.

If you are running grbl version 1.0c the report is different. Let me know which version you have.

Thank’s Larry, the grbl version is 1.0c

Ok, then this is the current information:

Thank you again Larry, I have been trying to get my head round this, do I enter $10=4 for homing/limit switch status, I have been trying that and get the reply ok

No, that’s the wrong bit to set. It is bit 4 which equates to decimal 16. So, you would enter $10=16 to get the homing/limit switch status. I would recommend that you also turn on Machine Position and Work Position so that programs like UCGS will respond as you would expect.

So, at least for testing set $10=19 to get homing/limit switch status, Machine Position and Work position reported for the status command (?).

Here is what you should see in the Serial Monitor display (where your Machine Position and Work Position will most likely be different ):


Thank’s Larry
Yes i did get the same as you – idle,MPos and the machine and work position are different, so I take it that my limit switches are all okay,I think it might be a wiring problem on the limit switches, I did think about getting the X controller, so I might rewire the limit switches and label them this time, I have read on here that shielded wire would be better, if it is what type of wire should I get .

Did you do the test to see if the status report changed when you pressed each switch?

Shielded wiring made it work for me, but others have had to do more to eliminate the noise. It just depends on how much noise you have with your machine.