Hello everyone,
A few months ago I bought a KFlop and Kstep combination attracted by the possibility to build a closed loop stepper system. My only earlier attempt in CNC was to use Mach3, but I found it not quite reliable enough. Tom was very helpful in answering my questions while I was taking the first steps on the road to set up my system. As his answers may help someone else as well, below the whole email chain:
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2012/07/14 Eero Haahti:
Hello Tom,
Finally during my summer holidays I have had time to rebuild my router and start to study the KFlop/KStep boards. I guess the setting up is going ok. Going to try the open loop stepper system first before closing the loop.
I have some odd behaviour when trying to flash the user memory with my settings. Following the help file it seems to start ok saying something approximately "Writing to Flash Memory". Then I get the following screens and after them I have to do a Flash recovery before KMotion can connect to the board again. I tried now three times and every time with the same result. Am I doing something wrong?
The other question is about microstepping. Is KStep set to 16microstep/Step in the hardware. I don't see any mention or any jumper setting for microsteps. And following this should I set the KFlop Channel config to "Step Dir" or Microstep , and later with closed loop to "CL Step" or "CL Micro"?
I haven't connected the board to my router yet... I wan't to be sure the settings are right first.
All the best,
Eero
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2012/07/14 Tom Kerekes:
Hi Eero,
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I don't know why you are getting that Exception.* I just tied it with V4.29 and it works ok for me.* But there is no reason for you to Flash User Data and we do not recommend it.* It is simpler to initialize your settings each time with a C program.* Flashing User programs is usually only required if you are running stand alone without a PC to configure the board.
*
KSTEP is fixed at 16microsteps/step.* We don't see any benefit to reduce it to a lower setting.
*
When using KSTEP use "Step Dir" or "CL Step" modes.
*
Regards
TK
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2012/7/15 Haahti Eero:
Thanks Tom for your quick reply even during weekend.
I understood that flashing the settings was a secure way of having the starting setup always the same, but as I'm the only one using the machine I guess it doesn't make any difference and may even be a better practice.
One more question for now - there will probably be many later on: KStep is fixed at 16 microsteps/step, but I'm using Step Dir output from KFlop. Does this mean that KFlop sends 200 steps/revolution to KStep to drive my steppers correctly? - or do I have to include these microsteps in my settings? I ask this because of the following:
Following the help file I understand that when configuring KFlop one has to use inches not mm as unit. Am I right?
I have a millimeter system (as most of Europe). If I understand, the "InvDistPerCycle" setting tells KFlop to send the right amount of steps to the KStep and the steppers to move the correct distance.
All my lead screws have a pitch of 4mm. *1 inch travel translates to 6.35 revolution and one revolution being 50 full cycles results in *InvDistPerCycle = 6.35 x 50 =*317.5 (cycles/1"). Am I right?*
Then in the beginning of my G-codes I include G21 (mm units) and after that I can comfortably use my mm distances. I tested my setup with these settings.
A G-code:
G90
G21
F5000
G1 Y0
G1 Y80
G1 Y0
M2
should move the Y axis for 20 full revolutions (= 80 mm), but in reality it only moved slightly less then one full turn. It did return exactly to the same spot (G1 Y0).
Obviously there is something I didn't get right.
I'm sure there is some very simple explanation for this and I'm looking forward to your answer.
Regards
Eero
P.S. I didn't test the setup with G20, but I guess that doesn't make any difference...
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2012/07/16 Tom Kerekes:
Hi Eero,
*
Yes invDistPerCycle is not used with Step/Dir Drives like KSTEP.* KSTEP does 16x microstepping so there is 3200 steps per revolution.* You will need to determine the resolution in counts per inch for your system based on any gear ratios and leadscrew pitch.* This should be entered in:
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KMoiotnCNC | Tool Setup | Trajectory Planner | Axis Parametes | Counts per inch
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Although the configuration setting for KMotionCNC are in inches the GCode can be in mm or inches depending on G20 or G21.
*
You can also set the max speeds and acceleration in units of inches and seconds in the Too Setup | Trajectory Planner Screen.
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G0 moves perform independent axis motions and use the settings for the Axes Parameters in KFLOP.* Coordinated Motions uch as G1,G2,G3 us the trajectory planner settings.
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It would be good if you asked these questions on the cnczone forum.
*
Regards
TK