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Old 07-28-2017, 07:13 PM   #71
chucketn
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I am printing Olsson's case for my RT controller. I have the bottom half printed, took over 9 hours. Had a problem printing the top half. The external mosfet in the heat bed circuit failed in the on condition. Luckily, I noticed the bed temp climbing and disconnected the wires to the bed. Shortly thereafter, the Y axis hung, causing many missed steps, which and caused a large level shift, ruining the print at 8 hours + . I will attempt the top half again when the replacement mosfet comes in.
For ChuckF, I can't remember now, but was your code based on Bob Pratl's code?


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Old 07-29-2017, 08:00 AM   #72
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Never Mind - Try it again after some sleep . .



Last edited by Foozer; 07-29-2017 at 08:22 AM. Reason: Bad math
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Old 07-29-2017, 08:44 PM   #73
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Quote:
Originally Posted by billanygard View Post
I have read a little in an "sidethread" about another solution but for now that is to heavy for me.

//Olsson
The problem is that no matter what you do you end up with a required division that includes a fraction of a step under some circumstances and stepper motors can only move whole steps. You will get errors if your script simply calculates a fixed number of steps per division.

Imagine a rotary table doing 36 divisions around the complete circle and the required number of divisions is 100.333333333 steps per division. So if you just round this to 100 steps, by the time you get right round the circle, you have missed 36 x 0.3333 = 12 steps.

The only way to fix this is to work out a way of distributing those missing steps around the circle. In our imaginary example, if you moved 101 steps every third division, your problem is solved.

Work out how to code that and your problem will go away.
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Old 07-30-2017, 03:06 AM   #74
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float Multiplier = (StepsPerRotation * TableRatio)/360.00;

From: ToMove = (Degrees*Multiplier);
to: ToMove = round(Degrees * Multiplier);

Should get you close . . . At least
Serial.print("ToMove # Steps = ");
ToMove = round(Degrees * Multiplier),
Serial.println(ToMove);
Degrees = Degrees + 1;
if(Degrees==361)Degrees=0;
delay(500);
shows 360 degrees as 1200 steps . . .


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