in position control: fixed never ending errormessage on wrong output control device.

ChangeLog

@@ -1,3 +1,8 @@
+2023-02-07:
+- position control is now working. has still some glitches
+  with negative Kp, Ki and Kd values. But in general it is working.
+- fixed: set mode to POSCTL_MODE_OFF if an output error occured.
+
 2022-12-07:
 - dump files will continussly loop
 - fixed: dumpfile is not setting the frame size to the videodev.conf_height

posctl.cc

@@ -639,7 +639,7 @@ void PosCtl::CalibModeStart(int x, int y) {
 	calib_pos.y = y;
 
 	calib_mode = POSCTL_CALIB_MODE_DELTA;
-	OutputWriteStop();
+	if (OutputWriteStop()) mode = POSCTL_MODE_OFF;
 	gettimeofday (&calib_timestamp, NULL);
 	gdk_threads_add_idle(cb_thread_posctl, NULL);
 };
@@ -671,7 +671,7 @@ void PosCtl::CalibModeDelta(int x, int y) {
 		calib_pos.x = x;
 		calib_pos.y = y;
 
-		OutputWriteValue(0, CALIB_MAXSPEED);
+		if (OutputWriteValue(0, CALIB_MAXSPEED)) mode = POSCTL_MODE_OFF;
 
 		gettimeofday (&calib_timestamp, NULL);
 		gdk_threads_add_idle(cb_thread_posctl, NULL);
@@ -696,13 +696,13 @@ void PosCtl::CalibModeAxis(int x, int y) {
 		if (calib_mode ==  POSCTL_CALIB_MODE_AXIS1)	{
 			calib_axis1_v = fp - calib_rot_v;
 			calc_vec2anglelen(&calib_axis1_v, &calib_axis1);
-			OutputWriteStop();
-			OutputWriteValue(1, CALIB_MAXSPEED);
+			if (OutputWriteStop()) mode = POSCTL_MODE_OFF;
+			else if (OutputWriteValue(1, CALIB_MAXSPEED)) mode = POSCTL_MODE_OFF;
 		}
 		else if (calib_mode ==  POSCTL_CALIB_MODE_AXIS2)	{
 			calib_axis2_v = fp - calib_rot_v;
 			calc_vec2anglelen(&calib_axis2_v, &calib_axis2);
-			OutputWriteStart();
+			if (OutputWriteStart()) mode = POSCTL_MODE_OFF;
 		}
 
 		calib_mode++;
@@ -774,8 +774,8 @@ void PosCtl::Loop (int posx, int posy) {
 		axis_op[0] = pid_axis[0].Update(0.0, axis_pv[0]);
 		axis_op[1] = pid_axis[1].Update(0.0, axis_pv[1]);
 
-		OutputWriteValue(0, axis_op[0]);
-		OutputWriteValue(1, axis_op[1]);
+		if (OutputWriteValue(0, axis_op[0]) ||	OutputWriteValue(1, axis_op[1]))
+			mode = POSCTL_MODE_OFF;
 
 		axis_history_add(0, axis_pv[0], axis_op[0]);
 		axis_history_add(1, axis_pv[1], axis_op[1]);