#113 - Hard / Soft

Ricardo

Problem:
# 113 - Arc Interpolation algorithm selection:
0: Hard algorithm
1: Soft algorithm

Because using the "0-Hard algorithm" the Z axis does not move as programmed in the G-Code, the Z axis loses precision, 0.250mm?

pcarlini

1. 
   
2. between each hole Z axis goes up minus 0.25mm, it is the Z axis losing step.

Copy the code

Ricardo saids "it is possible to see the difference in the controller display...."

@Ricardo, send me the file and I will take a look if you like

Cncninja

Hey Ricardo,

Jessy is correct but may be difficult to understand her explanation. When you use the hard algorithm your axes must have the same steps per mm. The way the FPGA calculates the arc it can not have different axis resolutions or you will end up with oblong holes or axis that seem to lose steps etc. You can set your controller up 2 ways just use the soft algorithm or if it's just your z-axis that has a different resolution change your post-processor to only allow XY interpolation. I can only assume your mill must have different steps per/mm for Axes. If your axis do not loose steps when moved in a straight line then this is your problem, easy fix in your controller or post

JessyChen

In DDCS System, there is soft algorithm and hard algorithm; hard algorithm is processed by FPGA logic, the movement is very smoothy, and high precise; Soft algorithm is to cut the arc line to a lot of little small pieces. But only when the pulse equivalents of each axis which join into doing the circular interpolation are the same, the hard algorithm can work well; The soft algorithm has no request for pulse equivalents. So when the controller work for helix interpolation, it is better to use soft algorithm.No matter you choose the Soft algorithm or Hard algorithm, it cannot cause the losing step. Losing step must be some other reason. Soft or Hard algorithm only affect the good or bad status of the machinning.

Ricardo

you did not understand the problem, using calculation by Hardeware, the Z axis does not go up as programmed is not a loss of pulse, between each hole made the Z axis goes up minus 0.250mm, it is possible to see this difference in the controller display. In Software calculation mode, the Z axis is over correctly.

Thanks for your attention

JessyChen

between each hole Z axis goes up minus 0.25mm, it is the Z axis losing step.

Ricardo

Sorry I have photos to show here but I do not know additional.

The Z Axis receives the command to decrease to -12mm, controller sends to -16mm, and to rise to 3mm the controller sends to -1.5mm.