Sbase and/or Smoothieware + DRV8825 drivers makes my motors very noisy and vibrating + grinding sounds! May 22, 2016 12:35AM |
Registered: 9 years ago Posts: 245 |
Re: Sbase and/or Smoothieware + DRV8825 drivers makes my motors very noisy and vibrating + grinding sounds! May 22, 2016 02:48AM |
Registered: 8 years ago Posts: 5,232 |
Re: Sbase and/or Smoothieware + DRV8825 drivers makes my motors very noisy and vibrating + grinding sounds! May 22, 2016 04:24AM |
Registered: 9 years ago Posts: 245 |
Any idea on what to change in firmware, if possible?Quote
o_lampe
IIRC the step-pulse duration on some 32bit boards is pretty short. Don't remember exactly if it was a smoothie- or RRP firmware. ( dc42_delta version )
Re: Sbase and/or Smoothieware + DRV8825 drivers makes my motors very noisy and vibrating + grinding sounds! May 22, 2016 04:54AM |
Registered: 10 years ago Posts: 14,672 |
Quote
o_lampe
IIRC the step-pulse duration on some 32bit boards is pretty short. Don't remember exactly if it was a smoothie- or RRP firmware. ( dc42_delta version )
Re: Sbase and/or Smoothieware + DRV8825 drivers makes my motors very noisy and vibrating + grinding sounds! May 22, 2016 05:33AM |
Registered: 9 years ago Posts: 245 |
Whining. yea, I know I can increase or decrease current.Quote
dc42
Quote
o_lampe
IIRC the step-pulse duration on some 32bit boards is pretty short. Don't remember exactly if it was a smoothie- or RRP firmware. ( dc42_delta version )
I think you are referring to an issue that someone had with RepRapFirmware on RADDS with DRV8825 drivers. The DRV8825s need a wider step pulse and a longer interval between step pulses than the A4982 drivers used in the Duet, and RRF wasn't providing enough time for the DRV8825 when running at high speeds. The pulse timing isn't yet configurable in the config.g file for RRF, so Dan Newman did a patch to the RADDS port to lengthen the times.
The problem with DRV8825 drivers whining in fast decay mode is well-known. A solution that works for some is to increase the voltage drop of the motors by putting back-to-back diodes in series with them, see [cabristor.blogspot.co.uk].
My advice is to avoid DRV8825 drivers. Either stick to the A4982/A4988 series, or if you want higher microstepping then go for THB6128, TMC2100 or one of the other modern driver chips.
That is pure alien-spake Is it something like this? [www.watterott.com]Quote
dc42
The problem with DRV8825 drivers whining in fast decay mode is well-known. A solution that works for some is to increase the voltage drop of the motors by putting back-to-back diodes in series with them, see [cabristor.blogspot.co.uk]
Re: Sbase and/or Smoothieware + DRV8825 drivers makes my motors very noisy and vibrating + grinding sounds! May 22, 2016 07:53AM |
Registered: 10 years ago Posts: 14,672 |
Quote
dintid
Edit: I actually have read that article several times.. only thing I understood is that DRV8825 is bad when using higher input voltage than the voltage needed to drive the motor... He didn't quantify it though, so is it 12 to 3, 24 to 3 or 200 to 3?.. meaning it was rather useless for me aside from stating that there are tangible problems Associated with the 8825
Quote
Is it something like this? [www.watterott.com]
Re: Sbase and/or Smoothieware + DRV8825 drivers makes my motors very noisy and vibrating + grinding sounds! May 22, 2016 08:28AM |
Registered: 9 years ago Posts: 245 |
I find it odd how often people say someone need to adjust "decay", but there really isn't any way to do so for the average mortal.. I sure as heck can't do it.. don't even really know what it is.Quote
dc42
Quote
dintid
Edit: I actually have read that article several times.. only thing I understood is that DRV8825 is bad when using higher input voltage than the voltage needed to drive the motor... He didn't quantify it though, so is it 12 to 3, 24 to 3 or 200 to 3?.. meaning it was rather useless for me aside from stating that there are tangible problems Associated with the 8825
It's not a fixed ratio, because it depends on the inductance of the motor as well as the supply voltage.
The voltage you need to drive the motors depends on how fast you want to step them, so reducing the supply voltage will in some cases reduce the available movement speed. The voltage quoted on the data sheet is the voltage needed to hold the motor still at maximum rated current.
The main effect of the diodes isn't to reduce the supply voltage, it's to increase the decay rate of the motor current when using mixed decay mode.
Again really didn't grasp the entirety of what you said, but is the gist of it, that you think it might Work to hinder the undesireable noise of the 8825 (not talking about whine)?Quote
dc42
Quote
dintid
Is it something like this? [www.watterott.com]
They call that device a "protector", so although it appears to have 8 diodes, I suspect that it is actually a set of Schottky flyback diodes to carry the flyback current so that the driver chips don't have to. I have often wondered whether a similar arrangement would be effective in protecting stepper driver chips from motors being connected or disconnected with the power on.
Re: Sbase and/or Smoothieware + DRV8825 drivers makes my motors very noisy and vibrating + grinding sounds! May 22, 2016 08:30AM |
Registered: 9 years ago Posts: 245 |
Re: Sbase and/or Smoothieware + DRV8825 drivers makes my motors very noisy and vibrating + grinding sounds! May 22, 2016 10:20AM |
Registered: 8 years ago Posts: 5,232 |
Quote
dc42
They call that device a "protector", so although it appears to have 8 diodes, I suspect that it is actually a set of Schottky flyback diodes to carry the flyback current so that the driver chips don't have to. I have often wondered whether a similar arrangement would be effective in protecting stepper driver chips from motors being connected or disconnected with the power on
Re: Sbase and/or Smoothieware + DRV8825 drivers makes my motors very noisy and vibrating + grinding sounds! May 22, 2016 05:23PM |
Registered: 10 years ago Posts: 14,672 |
Quote
o_lampe
Quote
dc42
They call that device a "protector", so although it appears to have 8 diodes, I suspect that it is actually a set of Schottky flyback diodes to carry the flyback current so that the driver chips don't have to. I have often wondered whether a similar arrangement would be effective in protecting stepper driver chips from motors being connected or disconnected with the power on
I'm afraid all modern MOSFets already have an inbuilt flyback diode, so do the FET-based H-bridges.