Pulse Density Modulation

Hi all,

Pretty new to 3D printing and brought myself a Wanhao i3, it's currently running firmware v0.91. Having a lot of fun tweaking and trimming everything and learning heaps of stuff at the same time.

I have been posting on the Wanhao Google Groups forum, where there is an interesting thread about PID. We are comparing notes on extruder temperatures and improvements to the stock extruder setup, due to some mechanical failings by Wanhao (extruder bore hole 6.35mm for the 6mm heater cartridge). Then someone posts a very impressive heater curve (what can I say I am geek and have an interest in PID and microcontrollers). Anyway it turns out they have a newer firmware version and wondering if this is just a bang-bang controller output or is this the Pulse Density Modulation?

Curve images below




The link to the thread is below as well:

Wanhao Google Group Thread

Additionally, I am pretty aufait with C code but not so with C++, could someone point me to where the PDM code is in the Extruder.cpp file?

Thanks,
Ant

Edited 1 time(s). Last edit at 11/05/2015 03:27PM by Antscran.

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Looks more like dead time control then pid:-)

extruder.cpp only sets the PWM/PDM values in an array. In HAL.cpp is the timer interrupt that does conversion to PDM/PWM signals.

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Hi Repetier,

Thanks for the response and link.

Cheers,
Ant

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[www.coder-tronics.com]
[www.thingiverse.com]