Re: New experimental firmware: all kinematics in host December 27, 2017 11:43AM |
Registered: 11 years ago Posts: 126 |
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ekaggrat
the usb many times drops the connection
Re: New experimental firmware: all kinematics in host December 28, 2017 04:13PM |
Registered: 6 years ago Posts: 4 |
Re: New experimental firmware: all kinematics in host December 29, 2017 09:42AM |
Registered: 8 years ago Posts: 363 |
Re: New experimental firmware: all kinematics in host December 29, 2017 10:26AM |
Registered: 14 years ago Posts: 7,616 |
Generation 7 Electronics | Teacup Firmware | RepRap DIY |
Re: New experimental firmware: all kinematics in host December 29, 2017 11:01AM |
Registered: 14 years ago Posts: 107 |
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Traumflug
Technically, what Klipper does on the PC takes less than 10% of an ATmega's capabilities, so keeping this on the controller isn't exactly a challenge. Teacup does these calculations 500 times a second, Klipper only 25 times. How can a slower approach get the reception of being the better one?
Re: New experimental firmware: all kinematics in host December 29, 2017 11:46AM |
Registered: 14 years ago Posts: 7,616 |
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KevinOConnor
I don't want to get into a Teacup vs Klipper discussion.
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KevinOConnor
You've done an excellent job with Teacup!
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KevinOConnor
I don't know what you are referring to with "Klipper only 25 times"
Generation 7 Electronics | Teacup Firmware | RepRap DIY |
Re: New experimental firmware: all kinematics in host December 29, 2017 12:53PM |
Registered: 6 years ago Posts: 4 |
Re: New experimental firmware: all kinematics in host December 29, 2017 01:00PM |
Registered: 14 years ago Posts: 7,616 |
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KenshiHH
It's actually the first time i hear about the TeaCup Firmware but with such an attitude as a Developer i already decided to never give it a try.
Generation 7 Electronics | Teacup Firmware | RepRap DIY |
Re: New experimental firmware: all kinematics in host December 29, 2017 03:19PM |
Registered: 9 years ago Posts: 138 |
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Traumflug
Had a look at the firmware code now. Nice work! Quite readable once one groks this DECL_... mechanism.
Of course I'm curious how klipper manages to about double the maximum step rate compared to Teacup. After reading sources I think it's because there is no stepper motor synchronisation. At least I can find none. Each movement command is for one stepper only, so the only synchronisation is that the host sends commands in a tight sequence.
Now, assuming that such a command is 6 bytes, it takes about ((8 data bits + 1 stop bit) * 6 bytes) / 250000 baud = 0.224 ms to send a command. A movement involving 3 steppers (quite common: X, Y, E) has an offset of 0.448 ms or, at 100'000 steps/seconds, of 44 steps. Being 44 steps off track is quite a bit for my taste.
Did I miss something with my considerations?
That said, I do see chances for klipper. It could learn synchronized movements. Adding acceleration, too, would make it very similar to the original RepRap firmware, but that's not neccessary. For acceleration, one update every 2 ms is sufficient. Then it's similar to Teacup firmware with ACCELERATION_TEMPORAL, which currently does neither acceleration nor lookahead, but evenly distributes all participating steppers like klipper. It'd need a parser for the klipper protocol, of course.
Re: New experimental firmware: all kinematics in host December 29, 2017 06:35PM |
Registered: 14 years ago Posts: 7,616 |
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Rossini
After reading sources I think it's because there is no stepper motor synchronisation. At least I can find none. Each movement command is for one stepper only, so the only synchronisation is that the host sends commands in a tight sequence.
Now, assuming that such a command is 6 bytes, it takes about ((8 data bits + 1 stop bit) * 6 bytes) / 250000 baud = 0.224 ms to send a command. A movement involving 3 steppers (quite common: X, Y, E) has an offset of 0.448 ms or, at 100'000 steps/seconds, of 44 steps. Being 44 steps off track is quite a bit for my taste.
Generation 7 Electronics | Teacup Firmware | RepRap DIY |
Re: New experimental firmware: all kinematics in host December 30, 2017 03:26AM |
Registered: 11 years ago Posts: 10 |
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Traumflug
Thanks for the charming words, but I disagree. Teacup always came with excellent performance. It comes with not hackish, but well designed code. It has demonstrated to do 1'600'000 steps/seconds (right, that's 1.6 MHz of synchronized stepper movements). It does evenly distributed stepper steps, avoiding Bresenham. It comes with a dedicated configuration and build application.
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Traumflug
Still it's only reason of existence is received as kind of a really last resort for those poor guys who can't even afford a $30 RAMPS.
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Traumflug
My personal conclusion about this is that technical quality doesn't really matter as long as the result somehow gets a printer moving. There's something else which makes people using a controller software solution. Klipper is apparently much better at this "something else".
Re: New experimental firmware: all kinematics in host December 30, 2017 06:15AM |
Registered: 11 years ago Posts: 19 |
Re: New experimental firmware: all kinematics in host December 30, 2017 07:49AM |
Registered: 14 years ago Posts: 7,616 |
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hg42
this sounds like heavily praising yourself, but I think you refer to Triffid Hunter's work?
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hg42
Please look at it from a users point of view.
For a user it's totally unimportant (and not under his control or visibility), how well designed the code is. (S)He simply doesn't see it.
And if it comes to the wanted feature X the software wins, that provides X over a software that doesn't.
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hg42
Now look at Klipper...it already has all I need, mainly delta and corexy kinematics and most wanted by me: physical exact stepping without tricks.
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hg42
You could make a modular system, using an Arduino Nano (2-5 EUR) for each single task.
E.g.
* a single axis with stepper and endstops
* an extruder with heater and temperature
* a heated bed controller
just add stepper drivers or MOSFET modules.
You will never run out of computing power.
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hg42
If you need something more tightly coupled like a delta, it may be better to gather these on an MCU with more power, like a fast 32bit controller.
Generation 7 Electronics | Teacup Firmware | RepRap DIY |
Re: New experimental firmware: all kinematics in host December 30, 2017 11:29AM |
Registered: 14 years ago Posts: 107 |
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Traumflug
Taken from one of the descriptions as the frequency of how often stepper speeds are updated. One can do only a pretty limited number of stepper commands over 115200 baud, after all, certainly much less than the claimed 500'000 steps/second for each stepper. I think this is what you call "compressing and sending".
Re: New experimental firmware: all kinematics in host December 30, 2017 11:33AM |
Registered: 14 years ago Posts: 107 |
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ThomasSc
How uninstall klipper?
How to set the right code back to common micro-controllers for /dev/ttyACM0?
If set serialport /dev/ttyACM0 in Octoprint there is no connection.
Thank you.
Re: New experimental firmware: all kinematics in host December 30, 2017 12:08PM |
Registered: 14 years ago Posts: 7,616 |
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KevinOConnor
Your assertion that this can not run at 115200 is absurd. It's regularly done. You could have easily installed the software and proven that to yourself.
Generation 7 Electronics | Teacup Firmware | RepRap DIY |
Re: New experimental firmware: all kinematics in host December 30, 2017 12:22PM |
Registered: 8 years ago Posts: 363 |
Re: New experimental firmware: all kinematics in host December 30, 2017 12:53PM |
Registered: 14 years ago Posts: 7,616 |
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obelisk79
all of a sudden Traumflug goes on the offensive.
Generation 7 Electronics | Teacup Firmware | RepRap DIY |
Re: New experimental firmware: all kinematics in host December 30, 2017 01:06PM |
Registered: 8 years ago Posts: 363 |
Re: New experimental firmware: all kinematics in host December 30, 2017 02:17PM |
Registered: 11 years ago Posts: 10 |
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Klipper uses the same tricks as everybody else. Pre-calculate movements, then approximate steps. As far as I can see, acceleration is done on the host side, so it can accelerate by stair-stepping only. Stair-stepping is fine, but not "physically exact".
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And then Klipper puts the performance and reliability bottleneck, serial communications, into one of the most sensible places: between step calculations and step executions
Re: New experimental firmware: all kinematics in host December 30, 2017 02:39PM |
Registered: 11 years ago Posts: 10 |
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The only absurd here is that you can't even tell us how often stepper speeds are updated. Instead you point to some documentation like a broken record. Documentation which does not answer the question.
Re: New experimental firmware: all kinematics in host December 30, 2017 03:13PM |
Registered: 11 years ago Posts: 10 |
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My personal conclusion about this is that technical quality doesn't really matter as long as the result somehow gets a printer moving
Re: New experimental firmware: all kinematics in host December 30, 2017 03:57PM |
Registered: 11 years ago Posts: 126 |
Re: New experimental firmware: all kinematics in host December 30, 2017 04:07PM |
Registered: 6 years ago Posts: 4 |
Re: New experimental firmware: all kinematics in host December 30, 2017 04:13PM |
Registered: 10 years ago Posts: 20 |
He got it here.Quote
hg42
you still did not answer from where you got the number 25.
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FEATURES
Klipper touts several “compelling features”:
Each stepper event is scheduled with a precision of 25 microseconds or better. The software does not use kinematic estimations (such as the Bresenham algorithm). It calculates precise step times based on the physics of acceleration and the physics of the machine kinematics. More precise stepper movement translates to quieter and more stable printer operation.
Re: New experimental firmware: all kinematics in host December 30, 2017 04:14PM |
Registered: 11 years ago Posts: 126 |
Re: New experimental firmware: all kinematics in host December 30, 2017 05:11PM |
Registered: 8 years ago Posts: 363 |
Re: New experimental firmware: all kinematics in host December 30, 2017 05:40PM |
Registered: 6 years ago Posts: 4 |
Re: New experimental firmware: all kinematics in host December 30, 2017 06:23PM |
Registered: 10 years ago Posts: 14,684 |
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KenshiHH
while marlin completly fails and runs the steppers really noisy, klipper runs much smoother and faster
Re: New experimental firmware: all kinematics in host December 30, 2017 06:46PM |
Registered: 14 years ago Posts: 107 |
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KenshiHH
back to topic.
made a comparrison between marlin and klipper with the same gcode file.
printed with pla at 100mm/s for the inner and outerwall at a 3000 acceleration.
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Marlin Printtime: 2h22m
Klipper Print Time: 1h12m