V0 Fysetc kit control board question & sensorless homing issue.

[Champ1800]

Hi All,

 

I have a just finished building a Fysetc kit V0.2 kit with a Cheatah V0 board. Does anyone know how to measure or adjust the stepper motor currents for these? Obviously I want to see about maxing this thing out eventually but I also want to see what I am at now.

I have downloaded the board details from their github https://github.com/FYSETC/Cheetah_V3.0 but I can't see anything.

The stepper motor 35HSH7402-24B-300A says it is rated for 4.2V 1.5A. From what I have worked out so far I think that the control board is giving 3.3V max to these (how do I measure the the actual Voltage & Amps to them?).

Separately I am also having issues with sensorless homing. When the print head is parked, X60,Y0 & I home it the X does not move & it thinks it has now homed even though it is at X60. I have set the sensitivity to 100 (255 being the most sensitive & lower number = less sensitive). I don'e know how much lower I can go on this but I also don't want to cause any other issues.

I am having some electrical issues too, getting low voltage warning to stepper motors. The main 24V power supply to the unit is not fluctuating at all when it is running. I am going to pull every wire & chck if there is any damage or bas crimping this weekend. It is the pre made wiring kit that came with it but you never know. Other than that I am at a loss on this one.

 

Thanks in advance for the help 

 

CHEETAH V3.0_SCH.pdf CHEETAH V3.0 Position.pdf X-Y motor 35HSH7402-24B-300A.pdf

[WarHammerTF]

I have 2 Fysetc V0.2 kits that exhibit the exact same issues along with the various mcu errors.

I have fixed one of them. I tried changing out the Pi and most all of the wiring without resolving the issue. Verified the p/s and that the pulleys were not skipping etc.

I am using the Fysetc printer.cfg. I played around a bit with the sensitivity and ended up at 110 as that gave a bit softer end of travel stop.

What got rid of the mcu errors was a new Cheetah v3.0 board install. The vendor I bought the kits from sent me one board when I asked about all the issues. 

On my printer.cfg in the print_end macro the last line is: G0 X60 Y{max_y} F3600          ; park nozzle at rear. Any home after this gives the behavior you indicated. I added a G28 Z line after the above referenced last line in the macro and that has worked for some 30+ hours of printing jobs since. I think this is sort of odd behavior from the printer so there could be some underlying setting or something else that is wrong that the G28 Z just bandaids. I submitted to Voron support on Discord and they could not pinpoint anything else. 

On the second V0.2 I have changed out some of the wiring and reseated what was not changed, made a fresh RPi SD card, reflashed the Cheetah, verified the stepper motor pulleys are not slipping etc. Prints anywhere from 5 to 35 minutes and then mcu errors out like the first printer. I guess I am going to order a new Cheetah and give that a go. 

I have to say I am not a huge fan of sensorless homing.