carousel.comp: Add some error detection, decel time and graycode encoding

1) Make it possible to explicity choose graycode encoding tather than rely
on default.

2) Interpret graycode all-zeros as max pockets rather than pocket zero (invalid)

3) Allow decel-time to be programmed even without an alignment phase

4) Only set "ready" when everything has stopped, and after a final position
check.


Signed-off-by: andypugh <andy@bodgesoc.org>

Author: andypugh

src/hal/components/carousel.comp

@@ -116,7 +116,7 @@ pin in float rev-dc "Velocity or duty cycle when reverse rotation is desired";
 pin in float hold-dc "Duty cycle when carousel is in-position (to hold against stop)";
 pin in float align-dc """Use this pin to set the speed of a slower alignment move once the changer is in position. Such a system almost
 certainly needs decel-time setting too""";
-pin in float decel-time "Time to wait for carousel to stop before final alignment";
+pin in float decel-time "Time to wait for carousel to stop before final alignment and position check";
 pin in signed counts "Connect to the rawcounts of an encoder or a stepgen in 'counts' mode";
 pin in signed scale = 100 "The number of stepgen or encoder counts between successive pockets";
 pin in signed width = 0   "How far each side of the exact scale to signal a new pocket";
@@ -167,6 +167,8 @@ int default_dir = 2;
 int default_sense = 4;
 int default_parity = 0;
 
+static bool err_once = 0;
+
 #define MAX_CHAN 8
 static int pockets[MAX_CHAN] = {-1};
 RTAPI_MP_ARRAY_INT(pockets, MAX_CHAN, "The number of pockets in each carousel")
@@ -202,6 +204,7 @@ FUNCTION(_){
         for(mask = new_pos >> 1 ; mask != 0 ; mask = mask >> 1){
             new_pos ^= mask;
         }
+        if (new_pos == 0) new_pos = inst_pockets; // all zeros != pocket zero
         break;
     case 'B': // Straight Binary
         align_pin = strobe;
@@ -380,7 +383,7 @@ FUNCTION(_){
             motor_vel = rev_dc;
             timer = rev_pulse;        
             state = 3;
-        } else if (align_dc != 0) {
+        } else if (decel_time > 0) {
             // stop and prepare for alignment
             motor_vel = 0;
             timer = decel_time;
@@ -390,7 +393,7 @@ FUNCTION(_){
             motor_rev = 0;
             motor_vel = hold_dc;
             active = 0;
-            if (enable) ready = 1;
+            if (enable && current_position == mod_pocket) ready = 1;
             state = 9;
         }
         break;
@@ -407,6 +410,10 @@ FUNCTION(_){
     case 5: //Waiting for carousel to stop
         timer -= fperiod;
         if (timer > 0) return;
+        if (align_dc == 0){
+            state = 8;
+            break;
+        }
         motor_vel = -align_dc;
         if (motor_dir == 1) {
             state = 6;
@@ -429,11 +436,17 @@ FUNCTION(_){
         motor_rev = 0;
         motor_vel = hold_dc;
         active = 0;
-        if (enable) ready = 1;
+        // final safety check for in-position
+        if (enable && current_position == mod_pocket) ready = 1;
         state = 9;
         break;
     case 9: //waiting for enable to go false
+        if (! ready && ! err_once){
+            rtapi_print_msg(RTAPI_MSG_ERR, "The toolchanger has failed the final alignment check");
+            err_once = 1;
+        }
         if (enable) return;
+        err_once = 0;
         state = 0;
         break;
     case 10: // start of homing
@@ -498,6 +511,8 @@ EXTRA_SETUP(){
     if (pockets[extra_arg] > 0) default_pockets = pockets[extra_arg];
     if (encoding[extra_arg] == NULL) {
         //it's already default_code
+    } else if (strncmp(encoding[extra_arg], "gray", 4) == 0) {
+        default_code = 'G';
     } else if (strncmp(encoding[extra_arg], "binary", 6) == 0) {
         default_code = 'B';
     } else if (strncmp(encoding[extra_arg], "bcd", 3) == 0) {