import asyncio
import numpy as np
from bluesky.protocols import Movable, Stoppable
from ophyd_async.core import (
DEFAULT_TIMEOUT,
AsyncStatus,
CalculatableTimeout,
CalculateTimeout,
ConfigSignal,
Device,
HintedSignal,
StandardReadable,
WatchableAsyncStatus,
WatcherUpdate,
observe_value,
)
from ophyd_async.epics.signal import epics_signal_r, epics_signal_rw, epics_signal_x
[docs]
class Mover(StandardReadable, Movable, Stoppable):
"""A demo movable that moves based on velocity"""
def __init__(self, prefix: str, name="") -> None:
# Define some signals
with self.add_children_as_readables(HintedSignal):
self.readback = epics_signal_r(float, prefix + "Readback")
with self.add_children_as_readables(ConfigSignal):
self.velocity = epics_signal_rw(float, prefix + "Velocity")
self.units = epics_signal_r(str, prefix + "Readback.EGU")
self.setpoint = epics_signal_rw(float, prefix + "Setpoint")
self.precision = epics_signal_r(int, prefix + "Readback.PREC")
# Signals that collide with standard methods should have a trailing underscore
self.stop_ = epics_signal_x(prefix + "Stop.PROC")
# Whether set() should complete successfully or not
self._set_success = True
super().__init__(name=name)
[docs]
def set_name(self, name: str):
super().set_name(name)
# Readback should be named the same as its parent in read()
self.readback.set_name(name)
[docs]
@WatchableAsyncStatus.wrap
async def set(
self, new_position: float, timeout: CalculatableTimeout = CalculateTimeout
):
self._set_success = True
old_position, units, precision, velocity = await asyncio.gather(
self.setpoint.get_value(),
self.units.get_value(),
self.precision.get_value(),
self.velocity.get_value(),
)
if timeout is CalculateTimeout:
assert velocity > 0, "Mover has zero velocity"
timeout = abs(new_position - old_position) / velocity + DEFAULT_TIMEOUT
# Make an Event that will be set on completion, and a Status that will
# error if not done in time
done = asyncio.Event()
done_status = AsyncStatus(asyncio.wait_for(done.wait(), timeout))
# Wait for the value to set, but don't wait for put completion callback
await self.setpoint.set(new_position, wait=False)
async for current_position in observe_value(
self.readback, done_status=done_status
):
yield WatcherUpdate(
current=current_position,
initial=old_position,
target=new_position,
name=self.name,
unit=units,
precision=precision,
)
if np.isclose(current_position, new_position):
done.set()
break
if not self._set_success:
raise RuntimeError("Motor was stopped")
[docs]
async def stop(self, success=True):
self._set_success = success
status = self.stop_.trigger()
await status
[docs]
class SampleStage(Device):
"""A demo sample stage with X and Y movables"""
def __init__(self, prefix: str, name="") -> None:
# Define some child Devices
self.x = Mover(prefix + "X:")
self.y = Mover(prefix + "Y:")
# Set name of device and child devices
super().__init__(name=name)
