ManuelW/grbl-LPC-CoreXY
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Spindle speed close to minimum fix.

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- When spindle speed is close to the minimum rpm, the PWM value would
be zero or lower than allowed. The computation error was caused by
setting the minimum PWM value to zero, when it should have been 1.

- Added a compiler check for minimum PWM to be greater than zero.

- Moved some of the spindle PWM macros to a more appropriate place in
the cpu_map.h.
This commit is contained in:
Sonny Jeon
2016-10-23 13:55:50 -06:00
parent 8e638f0054
commit 498dd62572
6 changed files with 72 additions and 18 deletions
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27
grbl/spindle_control.c
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@ -22,13 +22,6 @@
#include "grbl.h"
#ifdef SPINDLE_MINIMUM_PWM
#define SPINDLE_PWM_MIN_VALUE SPINDLE_MINIMUM_PWM
#else
#define SPINDLE_PWM_MIN_VALUE 0.0
#endif
#define SPINDLE_PWM_RANGE (SPINDLE_PWM_MAX_VALUE-SPINDLE_PWM_MIN_VALUE)
#ifdef VARIABLE_SPINDLE
static float pwm_gradient; // Precalulated value to speed up rpm to PWM conversions.
#endif
@ -142,24 +135,28 @@ void spindle_stop()
// Called by spindle_set_state() and step segment generator. Keep routine small and efficient.
uint8_t spindle_compute_pwm_value(float rpm) // 328p PWM register is 8-bit.
{
uint8_t pwm_value;
rpm *= (0.01*sys.spindle_speed_ovr); // Scale by spindle speed override value.
// Calculate PWM register value based on rpm max/min settings and programmed rpm.
if ((settings.rpm_min >= settings.rpm_max) || (rpm >= settings.rpm_max)) {
// No PWM range possible. Set simple on/off spindle control pin state.
sys.spindle_speed = settings.rpm_max;
return(SPINDLE_PWM_MAX_VALUE);
} else if (rpm < settings.rpm_min) {
if (rpm == 0.0) {
pwm_value = SPINDLE_PWM_MAX_VALUE;
} else if (rpm <= settings.rpm_min) {
if (rpm == 0.0) { // S0 disables spindle
sys.spindle_speed = 0.0;
return(SPINDLE_PWM_OFF_VALUE); }
else {
pwm_value = SPINDLE_PWM_OFF_VALUE;
} else { // Set minimum PWM output
sys.spindle_speed = settings.rpm_min;
return(SPINDLE_PWM_MIN_VALUE);
pwm_value = SPINDLE_PWM_MIN_VALUE;
}
} else {
} else {
// Compute intermediate PWM value with linear spindle speed model.
// NOTE: A nonlinear model could be installed here, if required, but keep it light-weight.
sys.spindle_speed = rpm;
return(floor( (rpm-settings.rpm_min)*pwm_gradient + (SPINDLE_PWM_MIN_VALUE+0.5)));
pwm_value = floor( (rpm-settings.rpm_min)*pwm_gradient + (SPINDLE_PWM_MIN_VALUE+0.5));
}
return(pwm_value);
}
#endif