PID Loop for stepper motors

Also maxvel and maxaccel INI settings seem to be missing from all axis except X


# Fourth axis, Joint3
[AXIS_3]
TYPE = ANGULAR
HOME = 0.0
BACKLASH = 0.000
INPUT_SCALE = 4000
OUTPUT_SCALE = 1.000
MIN_LIMIT = -110.0
MAX_LIMIT = 110.0
FERROR = 2.000
MIN_FERROR = 0.200
HOME_OFFSET = 0.0
HOME_SEARCH_VEL = 0.0
HOME_LATCH_VEL = 0.0
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = NO
HOME_SEQUENCE = 3
STEPGEN_MAXVEL = 11 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
STEPGEN_MAXACCEL = 22

Ah ok yeah don't worry about those, they are disabled, only x needs to work currently.

why are the speed values so slow i can get ACC 1200 with a Stepper on a RotTable
what happens if you increase this as the pulses are maybe to long

Ameone wrote:

Ah ok yeah don't worry about those, they are disabled, only x needs to work currently.

I'm confused, I though you were talking about an angular axis...

Ok maybe a little bit more detail on the project can be helpful: I'm currently working on using LinuxCNC to control a 5 degrees of freedom robotic arm, where each of the 5 axis is rotary. Each axis is moved by a stepper motor, and controlled through a rotary encoder attached to the axis shaft.The robot is a moveo 5 DOF, you can google it up to see how it is set up.
Currently, I'm only controlling a single axis only (axis 0 in the ini file) to speed up the configuration process and to avoid modifying each axis settings every time.
So, regarding axis 0 set up, the PID control was implemented thanks to your help (with the parameters you can find in the ini and hal files attached to the previous comment). The only problem is that the axis is moving really slow (both when jogging it and through gcode commands).

One reason I see for X axis slowness is that the acceleration value is so low that it would take 10 seconds to get to full velocity

Maybe you should be using the newer 2.8 version or Master for a non Cartesian robot arm, where there is a clear distinction between joints (moving machine part) and axis (Cartesian space coordinates).

Sometimes there is some murky confusion when trying to use a normally linearly defined axis (such as X, Y, or Z) as a rotary joint in versions previous to 2.8.