You should read this:
https://github.com/gnea/grbl/wiki/Gr...-Configuration
I'm new to CNC and have ready much on the setup, but am experiencing issues with the 3018 CNC kit from SainSmart. The issue is with the Z-axis when i issue move commands. The spindle travels past the intended position. It may be with the settings that I'm using. I have a limit switch set for the Z-axis and I'm using GRBL 1.1 with the Candle program they provide.
If I zero out the Z axis using the alligator clip probe and send the following I get an error will before i hit the full length of the Z axis... it moves to the correct position and sends an error.
G91 < ok
F1000 < ok
Z25 < ALARM:4
ok
I can manually jog 25 units just fine without error. Any ideas?
$$ < $0=10
$1=25
$2=0
$3=2
$4=0
$5=0
$6=0
$10=1
$11=0.010
$12=0.002
$13=0
$20=0
$21=1
$22=1
$23=0
$24=25.000
$25=500.000
$26=250
$27=2.000
$30=1000
$31=0
$32=0
$100=800.000
$101=800.000
$102=800.000
$110=1000.000
$111=1000.000
$112=600.000
$120=30.000
$121=30.000
$122=30.000
$130=300.000
$131=180.000
$132=45.000
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You should read this:
https://github.com/gnea/grbl/wiki/Gr...-Configuration
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Alarm 4 is a probe fail. You sure it's an alarm?
Your config has hard limits turned on. Are you hitting your limit switch?
I tested the limit switches by pressing them and observing the alarm condition in the command window of Candle. All three trigger a similar alarm state so I know they are connected and being monitored. If I manually jog to the limits, they stop the machine from going further as intended. However, the home procedure seems to completely ignore the limit switch on the Z axis (maybe the others to, but i don't get that far). The motor tries to spin past the limit switch and grinds for a while then stops on its own. I don't get it. I reviewed the suggested links which are great, but they simply say enable limit switches and homing and then do $H, but like i described... that doesn't work right. thoughts?
$H < ALARM:9
ok
Grbl 1.1f ['$' for help]
[MSG:Check Limits]
[MSG:'$H'|'$X' to unlock]
[CTRL+X] < Grbl 1.1f ['$' for help]
[MSG:Check Limits]
[MSG:'$H'|'$X' to unlock]
$X < [MSG:Caution: Unlocked]
ok
S500 < ok
ALARM:1
[MSG:Reset to continue]
It's not 100% clear to me what you have. I'm guessing your machine has the limit switch at the top the Z axis. If not it should be there. I'm also guessing that you have mechanical limit switches - aka "micro switches".
With mechanical "micro switches" if can you travel past them, they return to "normal". If your Z carriage travels too far during homing or you start homing on the wrong side of the switch, it might get confused. Can you actually see the switch getting hit?
But in general, if you aren't getting the switch to trigger it's either a bad switch, bad location or a loose connection somewhere. GRBL doesn't selectively ignore the switch. I don't know candle - does it show actual pin values? Very helpful diagnostics. Several control interfaces do - GRBL Panel does.
Yes they are micro switches wired in for 3 axis (see the attached pics). The Z-axis upper switch is getting pressed on the homing sequence, but the software isn't honoring the contact closure and continuing to spin the z-axis motor up until it stops on its own. I measure 5 volts across all three switches when they are open and 0 when they are closed, so that tells me the wiring is fine.
The fact that the controller can report an alarm for a limit would tell me that it's seeing the switches work. It seems like bad software or something isn't enabled correctly.
$H < ALARM:9
thank you for your assistance.
Just to close this out... it turns out it was a faulty controller board. Sainsmart agreed and sent a new board. I tried another woodpecker controller board and the limit switches and homing procedure work flawless. thanks folks for the help narrowing this down.