Merge pull request #230 from DiamondLightSource/794_stub_offsets_simp…

…lified

Add stub offsets to smargon

src/dodal/devices/smargon.py

@@ -1,8 +1,43 @@
+from enum import Enum
+
 from ophyd import Component as Cpt
-from ophyd import EpicsMotor, EpicsSignal
+from ophyd import Device, EpicsMotor
 from ophyd.epics_motor import MotorBundle
+from ophyd.status import StatusBase
 
 from dodal.devices.motors import MotorLimitHelper, XYZLimitBundle
+from dodal.devices.status import await_approx_value
+from dodal.devices.utils import SetWhenEnabled
+
+
+class StubPosition(Enum):
+    CURRENT_AS_CENTER = 0
+    RESET_TO_ROBOT_LOAD = 1
+
+
+class StubOffsets(Device):
+    """Stub offsets are used to change the internal co-ordinate system of the smargon by
+    adding an offset to x, y, z.
+    This is useful as the smargon's centre of rotation is around (0, 0, 0). As such
+    changing stub offsets will change the centre of rotation.
+    In practice we don't need to change them manually, instead there are helper PVs to
+    set them so that the current position is zero or to pre-defined positions.
+    """
+
+    parent: "Smargon"
+
+    center_at_current_position: SetWhenEnabled = Cpt(SetWhenEnabled, "CENTER_CS")
+    to_robot_load: SetWhenEnabled = Cpt(SetWhenEnabled, "SET_STUBS_TO_RL")
+
+    def set(self, pos: StubPosition) -> StatusBase:
+        if pos == StubPosition.CURRENT_AS_CENTER:
+            status = self.center_at_current_position.set(1)
+            status &= await_approx_value(self.parent.x, 0.0, deadband=0.1)
+            status &= await_approx_value(self.parent.y, 0.0, deadband=0.1)
+            status &= await_approx_value(self.parent.z, 0.0, deadband=0.1)
+            return status
+        else:
+            return self.to_robot_load.set(1)
 
 
 class Smargon(MotorBundle):
@@ -20,17 +55,15 @@ class Smargon(MotorBundle):
     phi: EpicsMotor = Cpt(EpicsMotor, "PHI")
     omega: EpicsMotor = Cpt(EpicsMotor, "OMEGA")
 
-    stub_offset_set: EpicsSignal = Cpt(EpicsSignal, "SET_STUBS_TO_RL.PROC")
-    """Stub offsets are calibration values that are required to move between calibration
-    pin position and spine pins. These are set in EPICS and applied via the proc."""
-
     real_x1: EpicsMotor = Cpt(EpicsMotor, "MOTOR_3")
     real_x2: EpicsMotor = Cpt(EpicsMotor, "MOTOR_4")
     real_y: EpicsMotor = Cpt(EpicsMotor, "MOTOR_1")
     real_z: EpicsMotor = Cpt(EpicsMotor, "MOTOR_2")
     real_phi: EpicsMotor = Cpt(EpicsMotor, "MOTOR_5")
     real_chi: EpicsMotor = Cpt(EpicsMotor, "MOTOR_6")
 
+    stub_offsets: StubOffsets = Cpt(StubOffsets, "")
+
     def get_xyz_limits(self) -> XYZLimitBundle:
         """Get the limits for the x, y and z axes.
 

src/dodal/devices/status.py

@@ -14,14 +14,28 @@ def value_is(value, **_):
     return SubscriptionStatus(subscribable, value_is, timeout=timeout)
 
 
-# Returns a status which is completed when the subscriptable contains a value within the expected_value list
 def await_value_in_list(
     subscribable: Any, expected_value: list, timeout: Union[None, int] = None
 ) -> SubscriptionStatus:
+    """Returns a status which is completed when the subscriptable contains a value
+    within the expected_value list"""
+
     def value_is(value, **_):
         return value in expected_value
 
     if not isinstance(expected_value, list):
         raise TypeError(f"expected value {expected_value} is not a list")
     else:
         return SubscriptionStatus(subscribable, value_is, timeout=timeout)
+
+
+def await_approx_value(
+    subscribable: Any,
+    expected_value: T,
+    deadband: float = 1e-09,
+    timeout: Union[None, int] = None,
+) -> SubscriptionStatus:
+    def value_is_approx(value, **_):
+        return abs(value - expected_value) <= deadband
+
+    return SubscriptionStatus(subscribable, value_is_approx, timeout=timeout)

src/dodal/devices/utils.py

@@ -4,6 +4,7 @@
 from ophyd import Component, Device, EpicsSignal
 from ophyd.status import Status, StatusBase
 
+from dodal.devices.status import await_value
 from dodal.log import LOGGER
 
 
@@ -105,3 +106,18 @@ def set_global_exception_and_log(status: Status):
     # Initiate the chain of functions
     wrap_func(starting_status, functions_to_chain[0], wrapped_funcs[-1])
     return full_status
+
+
+class SetWhenEnabled(Device):
+    """A device that sets the proc field of a PV when it becomes enabled."""
+
+    proc: EpicsSignal = Component(EpicsSignal, ".PROC")
+    disp: EpicsSignal = Component(EpicsSignal, ".DISP")
+
+    def set(self, proc: int) -> Status:
+        return run_functions_without_blocking(
+            [
+                lambda: await_value(self.disp, 0),
+                lambda: self.proc.set(proc),
+            ]
+        )

tests/devices/unit_tests/test_smargon.py

@@ -0,0 +1,66 @@
+from time import sleep
+from typing import Tuple
+
+import pytest
+from ophyd.sim import make_fake_device
+
+from dodal.devices.smargon import Smargon, StubPosition
+
+
+@pytest.fixture
+def smargon() -> Smargon:
+    return make_fake_device(Smargon)(name="smargon")
+
+
+def set_smargon_pos(smargon: Smargon, pos: Tuple[float, float, float]):
+    smargon.x.user_readback.sim_put(pos[0])
+    smargon.y.user_readback.sim_put(pos[1])
+    smargon.z.user_readback.sim_put(pos[2])
+
+
+def test_given_to_robot_disp_low_when_stub_offsets_set_to_robot_load_then_proc_set(
+    smargon: Smargon,
+):
+    smargon.stub_offsets.to_robot_load.disp.sim_put(0)
+
+    status = smargon.stub_offsets.set(StubPosition.RESET_TO_ROBOT_LOAD)
+    status.wait()
+
+    assert smargon.stub_offsets.to_robot_load.proc.get() == 1
+    assert smargon.stub_offsets.center_at_current_position.proc.get() == 0
+
+
+def test_given_center_disp_low_and_at_centre_when_stub_offsets_set_to_center_then_proc_set(
+    smargon: Smargon,
+):
+    smargon.stub_offsets.center_at_current_position.disp.sim_put(0)
+    set_smargon_pos(smargon, (0, 0, 0))
+
+    status = smargon.stub_offsets.set(StubPosition.CURRENT_AS_CENTER)
+    status.wait()
+
+    assert smargon.stub_offsets.to_robot_load.proc.get() == 0
+    assert smargon.stub_offsets.center_at_current_position.proc.get() == 1
+
+
+def test_given_center_disp_low_when_stub_offsets_set_to_center_and_moved_to_0_0_0_then_proc_set(
+    smargon: Smargon,
+):
+    smargon.stub_offsets.center_at_current_position.disp.sim_put(0)
+
+    set_smargon_pos(smargon, (1.5, 0.5, 3.4))
+
+    status = smargon.stub_offsets.set(StubPosition.CURRENT_AS_CENTER)
+
+    sleep(0.01)
+
+    assert smargon.stub_offsets.center_at_current_position.proc.get() == 1
+
+    assert not status.done
+
+    set_smargon_pos(smargon, (0, 0, 0))
+
+    status.wait()
+
+    assert smargon.stub_offsets.to_robot_load.proc.get() == 0
+    assert smargon.stub_offsets.center_at_current_position.proc.get() == 1

tests/devices/unit_tests/test_utils.py

@@ -1,9 +1,10 @@
 from unittest.mock import MagicMock, patch
 
 import pytest
+from ophyd.sim import make_fake_device
 from ophyd.status import Status
 
-from dodal.devices.utils import run_functions_without_blocking
+from dodal.devices.utils import SetWhenEnabled, run_functions_without_blocking
 from dodal.log import LOGGER, GELFTCPHandler, logging, set_up_logging_handlers
 
 
@@ -105,3 +106,15 @@ def test_status_points_to_provided_device_object():
     )
     returned_status.wait(0.1)
     assert returned_status.obj == expected_obj
+
+
+def test_given_disp_high_when_set_SetWhenEnabled_then_proc_not_set_until_disp_low():
+    signal: SetWhenEnabled = make_fake_device(SetWhenEnabled)(name="test")
+    signal.disp.sim_put(1)
+    signal.proc.set = MagicMock(return_value=Status(done=True, success=True))
+
+    status = signal.set(1)
+    signal.proc.set.assert_not_called()
+    signal.disp.sim_put(0)
+    status.wait()
+    signal.proc.set.assert_called_once()