Copying ECMC motor class to main repo

ophyd_devices/devices/psimotor.py

@@ -0,0 +1,125 @@
+""" Extension class for EpicsMotor
+
+This module extends the basic EpicsMotor with additional functionality. It
+exposes additional parameters of the EPICS MotorRecord and provides a more
+detailed interface for motors using the new ECMC-based motion systems at PSI.
+"""
+
+import warnings
+
+from ophyd import Component, EpicsMotor, EpicsSignal, EpicsSignalRO, Kind
+from ophyd.status import DeviceStatus, MoveStatus
+from ophyd.utils.errors import UnknownStatusFailure
+from ophyd.utils.epics_pvs import AlarmSeverity
+
+
+class SpmgStates:
+    """ Enum for the EPICS MotorRecord's SPMG state"""
+    # pylint: disable=too-few-public-methods
+    STOP = 0
+    PAUSE = 1
+    MOVE = 2
+    GO = 3
+
+
+class EpicsMotorMR(EpicsMotor):
+    """ Extended EPICS Motor class
+
+    Special motor class that exposes additional motor record functionality.
+    It extends EpicsMotor base class to provide some simple status checks
+    before movement.
+    """
+    tolerated_alarm = AlarmSeverity.INVALID
+
+    motor_deadband = Component(
+        EpicsSignalRO, ".RDBD", auto_monitor=True, kind=Kind.config)
+    motor_mode = Component(
+        EpicsSignal, ".SPMG", auto_monitor=True, put_complete=True, kind=Kind.omitted)
+    motor_status = Component(
+        EpicsSignal, ".STAT", auto_monitor=True, kind=Kind.omitted)
+    motor_enable = Component(
+        EpicsSignal, ".CNEN", auto_monitor=True, kind=Kind.omitted)
+
+    def move(self, position, wait=True, **kwargs) -> MoveStatus:
+        """ Extended move function with a few sanity checks
+
+        Note that the default EpicsMotor only supports the 'GO' movement mode.
+        """
+        # Reset SPMG before move
+        spmg = self.motor_mode.get()
+        if spmg != SpmgStates.GO:
+            self.motor_mode.set(SpmgStates.GO).wait()
+        # Warn if EPIC motorRecord claims an error
+        status = self.motor_status.get()
+        if status:
+            warnings.warn(
+                f"EPICS MotorRecord is in alarm state {status}, ophyd will raise",
+                RuntimeWarning
+                )
+        # Warni if trying to move beyond an active limit
+        # if self.high_limit_switch and position > self.position:
+        #     warnings.warn("Attempting to move above active HLS", RuntimeWarning)
+        # if self.low_limit_switch and position < self.position:
+        #     warnings.warn("Attempting to move below active LLS", RuntimeWarning)
+
+        try:
+            status = super().move(position, wait, **kwargs)
+            return status
+        except UnknownStatusFailure:
+            status = DeviceStatus(self)
+            status.set_finished()
+            # return status
+            raise
+
+
+class EpicsMotorEC(EpicsMotorMR):
+    """ Detailed ECMC EPICS motor class
+
+    Special motor class to provide additional functionality  for ECMC based motors.
+    It exposes additional diagnostic fields and includes basic error management.
+    """
+    USER_ACCESS = ['reset']
+    enable_readback = Component(EpicsSignalRO, "-EnaAct", auto_monitor=True, kind=Kind.normal)
+    enable = Component(
+        EpicsSignal, "-EnaCmd-RB", write_pv="-EnaCmd", auto_monitor=True, kind=Kind.normal)
+    homed = Component(EpicsSignalRO, "-Homed", auto_monitor=True, kind=Kind.normal)
+    velocity_readback = Component(EpicsSignalRO, "-VelAct", auto_monitor=True, kind=Kind.normal)
+    position_readback = Component(EpicsSignalRO, "-PosAct", auto_monitor=True, kind=Kind.normal)
+    position_error = Component(EpicsSignalRO, "-PosErr", auto_monitor=True, kind=Kind.normal)
+    # high_interlock = Component(EpicsSignalRO, "-SumIlockFwd", auto_monitor=True, kind=Kind.normal)
+    # low_interlock = Component(EpicsSignalRO, "-SumIlockBwd", auto_monitor=True, kind=Kind.normal)
+
+    # ecmc_status = Component(EpicsSignalRO, "-Status", auto_monitor=True, kind=Kind.normal)
+    error = Component(EpicsSignalRO, "-ErrId", auto_monitor=True, kind=Kind.normal)
+    error_msg = Component(EpicsSignalRO, "-MsgTxt", auto_monitor=True, kind=Kind.normal)
+    error_reset = Component(EpicsSignal, "-ErrRst", put_complete=True, kind=Kind.omitted)
+
+    def move(self, position, wait=True, **kwargs) -> MoveStatus:
+        """ Extended move function with a few sanity checks
+
+        Note that the default EpicsMotor only supports the 'GO' movement mode.
+        """
+        # Check ECMC error status before move
+        error = self.error.get()
+        if error:
+            raise RuntimeError(f"Motor is in error state with message: '{self.error_msg.get()}'")
+
+        return super().move(position, wait, **kwargs)
+
+    def reset(self):
+        """ Resets an ECMC axis
+
+        Recovers an ECMC axis from a previous error. Note that this does not
+        solve the cause of the error, that you'll have to do yourself.
+
+        Common error causes:
+        -------------------------
+        - MAX_POSITION_LAG_EXCEEDED : The PID tuning is wrong.
+        - MAX_VELOCITY_EXCEEDED : PID is wrong or the motor is sticking-slipping
+        - BOTH_LIMITS_ACTIVE : The motors are probably not connected
+        """
+        # Reset the error
+        self.error_reset.set(1, settle_time=0.1).wait()
+        # Check if it disappeared
+        if self.error.get():
+            raise RuntimeError(f"Failed to reset axis, still in error: '{self.error_msg.get()}'")