Revert "Set motor to start max velocity at start (#464)"

This reverts commit ef1c942.

src/ophyd_async/epics/motion/motor.py

@@ -116,7 +116,6 @@ async def prepare(self, value: FlyMotorInfo):
         )
 
         await self.set(fly_prepared_position)
-        await self.velocity.set(fly_velocity)
 
     @AsyncStatus.wrap
     async def kickoff(self):
@@ -183,7 +182,7 @@ async def stop(self, success=False):
     async def _prepare_velocity(
         self, start_position: float, end_position: float, time_for_move: float
     ) -> float:
-        fly_velocity = (end_position - start_position) / time_for_move
+        fly_velocity = (start_position - end_position) / time_for_move
         max_speed, egu = await asyncio.gather(
             self.max_velocity.get_value(), self.motor_egu.get_value()
         )
@@ -192,8 +191,7 @@ async def _prepare_velocity(
                 f"Motor speed of {abs(fly_velocity)} {egu}/s was requested for a motor "
                 f" with max speed of {max_speed} {egu}/s"
             )
-        # move to prepare position at maximum velocity
-        await self.velocity.set(abs(max_speed))
+        await self.velocity.set(abs(fly_velocity))
         return fly_velocity
 
     async def _prepare_motor_path(

tests/epics/motion/test_motor.py

@@ -216,9 +216,7 @@ async def test_valid_prepare_velocity(sim_motor: motor.Motor):
         fly_info.end_position,
         fly_info.time_for_move,
     )
-    assert (
-        await sim_motor.velocity.get_value() == await sim_motor.max_velocity.get_value()
-    )
+    assert await sim_motor.velocity.get_value() == 10
 
 
 @pytest.mark.parametrize(
@@ -296,7 +294,6 @@ async def wait_for_status(status: AsyncStatus):
     )
     # Test that prepare is not marked as complete until correct position is reached
     await asyncio.gather(do_set(status), wait_for_status(status))
-    assert await sim_motor.velocity.get_value() == 10
     assert status.done