SICS-501 Special one-shot move after changing direction for backlash

site_ansto/motor_dmc2280.c

@@ -2516,6 +2516,7 @@ static void DMCState_Moving(pDMC2280Driv self, pEvtEvent event) {
                   SICSLogWrite(line, eStatus);
                 }
                 set_lastMotion(self, self->currSteps, self->currCounts);
+                self->preseek = 2; /* special one-shot */
                 absolute = motCreep(self, target);
               }
             }
@@ -2555,6 +2556,8 @@ static void DMCState_Moving(pDMC2280Driv self, pEvtEvent event) {
                 }
                 cmdPosition(self, absolute);
                 self->subState = 3;
+                if (self->preseek == 2)  /* change of direction */
+                  self->preseek = 0;      /* don't do it again */
                 return;
               }
             }