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Shut down heaters during BL-Touch probe event

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The electro-magnetic interference from the bed and nozzle are affecting
the BL-Touch repeatability for some users.   This problem can be helped
by shutting down the heaters during the actual probe event and then
quickly turning them back on.

Because this code is messing with the heaters, it is written in a
paranoid manner.  It only turns the heaters back on if everything is
EXACTLY as it expects things to be.  The BL-Touch probe must have been
put into a deployed state less than 20 seconds prior, or the stow()
function will NOT turn the heaters on.

This code has been tested and works for both G28 and probing functions.
This commit is contained in:
Roxy-3D 2017-04-27 18:33:34 -05:00 committed by Roxy-3D
parent 3601f08e87
commit 6e8ecb908a
1 changed files with 46 additions and 0 deletions
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46
Marlin/Marlin_main.cpp
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@ -2065,7 +2065,49 @@ static void clean_up_after_endstop_or_probe_move() {
safe_delay(BLTOUCH_DELAY); safe_delay(BLTOUCH_DELAY);
} }
//
// The BL-Touch probes have a HAL effect sensor. The high currents switching
// on and off cause big magnetic fields that can affect the reliability of the
// sensor. So, for BL-Touch probes, we turn off the heaters during the actual probe.
// And then we quickly turn them back on after we have sampled the point
//
void turn_heaters_on_or_off_for_bltouch(const bool deploy) {
static int8_t bltouch_recursion_cnt=0;
static millis_t last_emi_protection=0;
static float temps_at_entry[HOTENDS];
#if HAS_TEMP_BED
static float bed_temp_at_entry;
#endif
if (deploy && bltouch_recursion_cnt>0) // if already in the correct state, we don't need to do anything
return; // with the heaters.
if (!deploy && bltouch_recursion_cnt<1) // if already in the correct state, we don't need to do anything
return; // with the heaters.
if (deploy) {
bltouch_recursion_cnt++;
last_emi_protection = millis();
HOTEND_LOOP() temps_at_entry[e] = thermalManager.degTargetHotend(e); // save the current target temperatures
HOTEND_LOOP() thermalManager.setTargetHotend(0, e); // so we know what to restore them to.
#if HAS_TEMP_BED
bed_temp_at_entry = thermalManager.degTargetBed();
thermalManager.setTargetBed(0.0);
#endif
}
else {
bltouch_recursion_cnt--; // the heaters are only turned back on
if (bltouch_recursion_cnt==0 && ((last_emi_protection+20000L)>millis())) { // if everything is perfect. It is expected
HOTEND_LOOP() thermalManager.setTargetHotend(temps_at_entry[e], e); // that the bltouch_recursion_cnt is zero and
#if HAS_TEMP_BED // that the heaters were shut off less than
thermalManager.setTargetBed(bed_temp_at_entry); // 20 seconds ago
#endif
}
}
}
void set_bltouch_deployed(const bool deploy) { void set_bltouch_deployed(const bool deploy) {
turn_heaters_on_or_off_for_bltouch(deploy);
if (deploy && TEST_BLTOUCH()) { // If BL-Touch says it's triggered if (deploy && TEST_BLTOUCH()) { // If BL-Touch says it's triggered
bltouch_command(BLTOUCH_RESET); // try to reset it. bltouch_command(BLTOUCH_RESET); // try to reset it.
bltouch_command(BLTOUCH_DEPLOY); // Also needs to deploy and stow to bltouch_command(BLTOUCH_DEPLOY); // Also needs to deploy and stow to
@ -2100,6 +2142,10 @@ static void clean_up_after_endstop_or_probe_move() {
} }
#endif #endif
#if ENABLED(BLTOUCH)
turn_heaters_on_or_off_for_bltouch(deploy);
#endif
if (endstops.z_probe_enabled == deploy) return false; if (endstops.z_probe_enabled == deploy) return false;
// Make room for probe // Make room for probe