Hello. I'm encountering a frequent problem whilst executing my pen plots. The machine is merrily plotting away when it suddenly seems to jam (there is a squealing sound), stops mid-plot and flies into the frame of the plotter, triggering the hard limits. This has happened to me now a number of times with different files, though the image is basically the same (parallel lines). Here is a snippet of the serial console at the moment of crash (it's a long file so didn't want to paste it all here). Thanks. [11:30:36] [ G1 F40000 X730.0 Y379.56284 Z-0.1000 ] ok [11:30:38] [ G1 F40000 X730.0 Y378.90283 Z-0.1000 ] ok [11:30:38] [ G1 F40000 X30.0 Y378.90283 Z-0.1000 ] ok [11:30:39] [ G1 F40000 X30.0 Y378.24283 Z-0.1000 ] ok [11:30:39] [ G1 F40000 X730.0 Y378.24283 Z-0.1000 ] ok [11:30:40] [ ALARM ] ALARM: 1 - Hard limit triggered. Machine position is likely lost due to sudden and immediate halt. Re-homing is highly recommended. [ G1 F40000 X730.0 Y377.58282 Z-0.1000 ] [11:30:40] [ ] ALARM: 1 - Hard limit triggered. Machine position is likely lost due to sudden and immediate halt. Re-homing is highly recommended. [ G1 F40000 X730.0 Y377.58282 Z-0.1000 ] [11:30:40] [ G1 F40000 X730.0 Y377.58282 Z-0.1000 ] ALARM:1 [11:30:40] [ G1 F40000 X730.0 Y377.58282 Z-0.1000 ] [MSG:Reset to continue] [11:30:41] [ G1 F40000 X730.0 Y377.58282 Z-0.1000 ] ok [11:30:41] [ G1 F40000 X30.0 Y377.58282 Z-0.1000 ] Grbl 1.1f ['$' for help] [11:30:41] [ G1 F40000 X30.0 Y377.58282 Z-0.1000 ] [MSG:Check Limits] [11:30:41] [ G1 F40000 X30.0 Y377.58282 Z-0.1000 ] [MSG:'$H'|'$X' to unlock] [11:30:41] [ ] error: 9 - G-code locked out during alarm or jog state [ G1 F40000 X30.0 Y377.58282 Z-0.1000 ]<hr>This error may just be a symptom of an earlier event:<br> ALARM: 1 - Hard limit triggered. Machine position is likely lost due to sudden and immediate halt. Re-homing is highly recommended. [11:30:41] [ ERROR ] error: 9 - G-code locked out during alarm or jog state [ G1 F40000 X30.0 Y377.58282 Z-0.1000 ]
Dial back your Max Rate in Grbl settings and try again. If its set too high the motors stall - making the sound you describe
Ok. I'll try that - strange though that sometimes the plot works fine and other times it stalls. Out of curiosity, does the Grbl max rate override the F number in the Gcode file? Currently I have both set to 40000. Also, I have had a bit of problem today with homing and the hard limits being triggered even though the head is no where near them. Could this also be the cause somehow?
The "sometimes" will be in sections long enough to get up to stall speed. Acceleration setting coming into play. Max speed is a limit, if F is 6000 and Max Rate is 5000 then it wont ever go faster than 5000. If F is 3000 and Max rate is 5000 then G0 moves will be 5000 and G1/2/3 will be 3000
Thanks. What would be the max limit for the steppers that OB ships with the acro? Mine seem to have a max of 36000 which is rather slow considering I could have it hooked up to a laser. I had been hoping for quicker plotting speeds so maybe a stepper upgrade? And how about the homing issue? I've now encountered it twice since starting this thread. The alarm is triggered when it hits the x limit before it's found the y limit. Any help appreciated!
Running Xtension Limits or other switches? Could be crosstalk from motor wires to limits wiring. Seperate them apart as a test. Speeds: trial and error - our profiles are very Conservative, refer the Grbl wiki for tuning instructions.
Over the years we had two types, not sure when yours was purchased. These are the "EMI hardened" ones: Xtension Limit Switch Kit Also see docs:blackbox:faq-emi [OpenBuilds Documentation]
