component orient "Provide a PID command input for orientation mode based on current spindle position, target angle and orient mode";

pin in  bit   enable      "enable angular output for orientation mode";
pin in  s32   mode        "0: rotate - shortest move; 1: always rotate clockwise; 2: always rotate counterclockwise";
pin in  float position    "spindle position input, unit 1 rev";
pin in  float angle       "orient target position in degrees, 0 <= angle < 360";
pin out float command     "target spindle position, input to PID command";
pin out float poserr      "in degrees - aid for PID tuning";

variable int   last_enable = 0;

option fp yes;

function _ "Update \\fBcommand\\fR based on \\fBenable\\fR, \\fBposition\\fR, \\fBmode\\fR and \\fBangle\\fR.";
author "Michael Haberler";


description """
This component is designed to support a spindle orientation PID loop by providing a 
command value, and fit with the motion spindle-orient support pins to support the M19 code.

The spindle is assumed to have stopped in an arbitrary position. The spindle
encoder position is linked to the  \\fBposition\\fR pin.
The  current value of the position pin is sampled on a positive edge on the \\fBenable\\fR pin, and 
\\fBcommand\\fR is computed and set as follows: floor(number of 
full spindle revolutions 
in the \\fBposition\\fR sampled on positive edge) 
plus \\fBangle\\fR/360 (the fractional revolution) +1/-1/0 depending on \\fBmode\\fR.

The \\fBmode\\fR pin is interpreted as follows:

0: the spindle rotates in the direction with the lesser angle, 
which may be clockwise or counterclockwise.

1: the spindle rotates always rotates clockwise to the new angle.

2: the spindle rotates always rotates counterclockwise to the new angle.
 

.SH HAL USAGE

On \\fBmotion.spindle-orient\\fR disconnect the spindle control and connect to the orient-pid 
loop:

loadrt orient names=orient
.br
loadrt pid    names=orient-pid
.br
net orient-angle  motion.spindle-orient-angle orient.angle
.br
net orient-mode   motion.spindle-orient-mode  orient.mode
.br
net orient-enable motion.spindle-orient       orient.enable orient-pid.enable
.br
net spindle-pos    ...encoder..position orient.position orient-pid.feedback
.br
net orient-command orient.command orient-pid.command
.br

""";

license "GPL";
;;
#include <rtapi_math.h>

FUNCTION(_) {

    double target_angle;
    double latched_position;

    if (enable) {
	if (enable ^ last_enable) {       // positive edge on enable
            latched_position = position; // sample now
            target_angle =  angle/360.0;
            switch (mode) {
            case 0: // shortest move
                command = floor(latched_position+0.5-target_angle) + target_angle;
                break;
            case 1: // always cw
                command = ceil(latched_position-target_angle)  + target_angle;
                break;
            case 2: // always ccw
                command = floor(latched_position-target_angle) + target_angle ;
                break;
	    }
	}
	poserr = (position - command) * 360.0;
    }
    last_enable = enable;
}