[Grbl_Esp32 Issue#455] Spindle PWM settings

#1 – bdring 于 2020-06-26

Try setting your values like this…

“
$30=24000.000
$31=0.000
$32=0
$33=5000.000
$34=0.000
$35=30.000
$36=100.000
“

Then do a reboot by either clicking the reset button on the ESP32 or sending [ESP444]RESTART.

It works for me on my test system.

#2 – karoria 于 2020-06-27

Thanks a lot. Will try today only.

#3 – karoria 于 2020-06-27

It seems there is a bug. I tried with two type of settings and the results were different. I used DSO to measure duty cycle. Following are settings:

Common settings:
$30=24000.000
$31=0.000
$32=0
$33=5000.000
$34=0.000

Case 1:
$35=30.000
$36=100.000
Measurements of spindle rpm sent via gcode Vs PWM Duty Cycle
10-12%
1000-14.5%
12000-46.5%
23000-78.4%
24000-99.5%

Case 2:
$35=60.000
$36=100.000
Measurements of spindle rpm sent via gcode Vs PWM Duty Cycle
10-23.5%
1000-25%
12000-43%
23000-61%
24000-99.5%

My observation from the above readings:
say total blank span out of 100%= 30 in first case and 60 in second case.
name it 3x. So the duty cycle before spindle min rpm shall be x and after max rpm shall be 2x.
Strange thing is at 23999 rpm the duty cycle remains 80% for first case and at 24000 it becomes 99.5% (theoretically 100%).

I hope this data might be useful and I am able to explain it well. Waiting for prompt response.

#4 – bdring 于 2020-06-27

I am not sure why you are having trouble. This is my test with results read from a logic analyzer.

0 = 0%
1 = 30%
1000 = 33%
12000 = 65%
23000 = 97.50%
24000 = 100%

S12000 Example

!image

The math is quite simple. It uses a classic map function as described here.

Before the map function it applies any speed overrides and makes sure you are in the min/max range.

#5 – karoria 于 2020-06-27

I use pin 17 for spindle pwm. I don’t use RMT steps. Does it have any connection to this problem? I suspect there is something in firmware to be enabled or disabled before compiling, which I use differently then you.

#6 – karoria 于 2020-06-28

OK. I found the Fix. It is those last 11 #define lines of config.h file which are active (not commented out) by default although you are not using piecewise linear spindle. I recommend to comment out those lines by default.
Thanks for time

#7 – karoria 于 2020-06-29

Reopening. Sorry, I messed up two different folders of code. That was not actual fix. Now I observe that “disabling limit pin pullup” causes the pwm output behave like those readings above. I use inverse logic limit switches and for that I use external pulldown resistors.
I can’t figure out how a limit switch pullup can cause malfunction in spindle pwm output. This happens in latest firmware as well as some 6 months old firmware.

#8 – bdring 于 2020-06-29

Can you paste your complete machine definition file here?

#9 – karoria 于 2020-06-29

Sure. I am out of station for 2 days. Will paste it when back to work.

#10 – karoria 于 2020-07-06

Sorry for long delay in submitting my machine definition file. Actually I was struggling to reproduce the same as I use inverse type settings in my machine PCB for limit switches. Most of the time I check the ESP32 Dev board unattached, I face problems of false triggering hard limits, door alarm etc. Now I am attaching config.h, cpu_map.h and defaults.h files which are as per old firmware. I am also struggling to get new firmware up and running as when I give M3 command, machine alarms for hard limit.
First thing first, I would highly appreciate getting a solution of the problem defined in this thread. I know this might take a good time of your efforts and thank you very much in advance for all that. Waiting for any clues…

#11 – bdring 于 2020-07-06

Could you please also paste your startup messages. I would like to know what version you are running.

#12 – karoria 于 2020-07-07

[ESP444]RESTART
[MSG:Restart ongoing]
ok
ets Jun 8 2016 00:22:57
rst:0xc (SWCPURESET),boot:0x13 (SPIFASTFLASH_BOOT)
configsip: 0, SPIWP:0xee
clkdrv:0x00,qdrv:0x00,ddrv:0x00,cs0drv:0x00,hddrv:0x00,wpdrv:0x00
mode:DIO, clock div:1
load:0x3fff0018,len:4
load:0x3fff001c,len:1216
ho 0 tail 12 room 4
load:0x40078000,len:9720
ho 0 tail 12 room 4
load:0x40080400,len:6352
entry 0x400806b8
[MSG:Axis count 3]
[MSG:Timed Steps]
[Controller:ENGILABS_V4]
Grbl 1.1f [‘$’ for help]
[MSG:Check Limits]
[MSG:’$H’|’$X’ to unlock]

Where I replaced CPUMAPESP32V3.5 to ENGILABSV4 in my file. I don’t use any wifi/bluetooth/telnet/sd features and all are disabled in config.h

#13 – bdring 于 2020-07-07

That is a very old version of Grbl_ESP32. Many issues have been fixed since then.

Please use the current version of the master or devt branches. We can provide support on those versions.

#14 – karoria 于 2020-07-07

Ok. I have some issues in latest master too. I will re-try that and update you.