Motor now ignores limit switch hit errors when homing

See comment in src/masterMacsAxis.cpp, line 640ff.

Makefile

@@ -9,6 +9,8 @@ ARCH_FILTER=RHEL%
 # Specify the version of asynMotor we want to build against
 motorBase_VERSION=7.2.2
 
+LIBVERSION=homeerror
+
 # These headers allow to depend on this library for derived drivers.
 HEADERS += src/masterMacsAxis.h
 HEADERS += src/masterMacsController.h

src/masterMacsAxis.cpp

@@ -629,42 +629,83 @@ asynStatus masterMacsAxis::doPoll(bool *moving) {
         }
 
         /*
-        Either the software limits or the end switches of the controller
-        have been hit. Since the EPICS limits are derived from the software
-        limits and are a little bit smaller, these error cases can only
-        happen if either the axis has an incremental encoder which is not
-        properly homed or if a bug occured.
+        If the motor is homing or has been homed, ignore limit switch errors.
+         */
+        int homing = 0;
+        int homed = 0;
+        getAxisParamChecked(this, motorStatusHome, &homing);
+        getAxisParamChecked(this, motorStatusHomed, &homed);
+
+        /*
+        Ignore limit switch errors when homing / motor has been homed or when
+        the motor is moving.
+
+        Background:
+        MasterMACS controllers move the motor outside the allowed range defined
+        by the "software limits" defined within the controllers because they
+        need to hit the physical end switch to determine the motor position. The
+        motor then rests close to the end switch, which might be outside the
+        controller-side software limits. This leads to this error, which is then
+        forwarded to the user even though nothing went wrong. The three checks
+        are here to prevent this:
+        - "homing": Is set at the start of a homing maneuver and removed once
+        the motor does not move anymore => Prevents the error from showing up
+        during the homing procedure
+        - "homed": Is set after a homing maneuver has been finished => Prevents
+        the error from showing up while the motor is resting idle outside the
+        software limits.
+        - "moving": Prevents the error from showing up when moving out of the
+        homing position.
+
+        If the motor hits the limits during normal operation, it is stopped by
+        the controller. Once stopped, moving is false and then the error is
+        shown to the user (because "homed" is not set).
+
+        Note: strictly speaking, it is not necessary to check homing because
+        moving would be set to true anyway. The check is here for clarity /
+        being explicit.
         */
-        if (positiveLimitSwitch() || negativeLimitSwitch() ||
-            positiveSoftwareLimit() || negativeSoftwareLimit()) {
+        if (!homing && !homed && !(*moving)) {
+            /*
+            Either the software limits or the end switches of the controller
+            have been hit. Since the EPICS limits are derived from the software
+            limits and are a little bit smaller, these error cases can only
+            happen if either the axis has an incremental encoder which is not
+            properly homed or if the motor moved outside the limits while homing
+            (but in that case, the error is not shown, see previous
+            if-statement).
+            */
+            if (positiveLimitSwitch() || negativeLimitSwitch() ||
+                positiveSoftwareLimit() || negativeSoftwareLimit()) {
 
-            // Distinction for developers
-            if (positiveLimitSwitch()) {
-                appendErrorMessage(shellMessage, sizeof(shellMessage),
-                                   "Positive limit switch.");
-            }
-            if (negativeLimitSwitch()) {
-                appendErrorMessage(shellMessage, sizeof(shellMessage),
-                                   "Negative limit switch.");
-            }
-            if (positiveSoftwareLimit()) {
-                appendErrorMessage(shellMessage, sizeof(shellMessage),
-                                   "Positive software limit.");
-            }
-            if (negativeSoftwareLimit()) {
-                appendErrorMessage(shellMessage, sizeof(shellMessage),
-                                   "Negative software limit.");
-            }
+                // Distinction for developers
+                if (positiveLimitSwitch()) {
+                    appendErrorMessage(shellMessage, sizeof(shellMessage),
+                                       "Positive limit switch.");
+                }
+                if (negativeLimitSwitch()) {
+                    appendErrorMessage(shellMessage, sizeof(shellMessage),
+                                       "Negative limit switch.");
+                }
+                if (positiveSoftwareLimit()) {
+                    appendErrorMessage(shellMessage, sizeof(shellMessage),
+                                       "Positive software limit.");
+                }
+                if (negativeSoftwareLimit()) {
+                    appendErrorMessage(shellMessage, sizeof(shellMessage),
+                                       "Negative software limit.");
+                }
 
-            // Generic error message for user
-            appendErrorMessage(
-                errorMessage, sizeof(errorMessage),
-                "Software limits or end switch hit. Try homing the motor, "
-                "moving in the opposite direction or check the SPS for "
-                "errors (if available). Otherwise please call the "
-                "support.");
+                // Generic error message for user
+                appendErrorMessage(
+                    errorMessage, sizeof(errorMessage),
+                    "Software limits or end switch hit. Try homing the motor, "
+                    "moving in the opposite direction or check the SPS for "
+                    "errors (if available). Otherwise please call the "
+                    "support.");
 
-            poll_status = asynError;
+                poll_status = asynError;
+            }
         }
 
         if (overCurrent()) {