fixes #33, fixes #34

APS_BlueSky_tools/devices.py

@@ -113,6 +113,7 @@ class ApsPssShutter(Device):
     * APS PSS shutters have separate bit PVs for open and close
     * set either bit, the shutter moves, and the bit resets a short time later
     * no indication that the shutter has actually moved from the bits
+      (see :func:`ApsPssShutterWithStatus()` for alternative)
     
     USAGE:
     
@@ -196,6 +197,99 @@ def run_and_delay():
         return status
 
 
+class ApsPssShutterWithStatus(Device):
+    """
+    APS PSS shutter
+    
+    * APS PSS shutters have separate bit PVs for open and close
+    * set either bit, the shutter moves, and the bit resets a short time later
+    * a separate status PV tells if the shutter is open or closed
+      (see :func:`ApsPssShutter()` for alternative)
+    
+    USAGE:
+    
+        shutter_a = ApsPssShutterWithStatus("2bma:A_shutter", name="shutter")
+        
+        shutter_a.open()
+        shutter_a.close()
+        
+        or
+        
+        %mov shutter_a "open"
+        %mov shutter_a "close"
+        
+        or
+        
+        shutter_a.set("open")       # MUST be "open", not "Open"
+        shutter_a.set("close")
+        
+    When using the shutter in a plan, be sure to use `yield from`.
+
+        def in_a_plan(shutter):
+            yield from abs_set(shutter, "open", wait=True)
+            # do something
+            yield from abs_set(shutter, "close", wait=True)
+        
+        RE(in_a_plan(shutter_a))
+        
+    The strings accepted by `set()` are defined in attributes
+    (`open_str` and `close_str`).
+    """
+    open_bit = Component(EpicsSignal, ":open")
+    close_bit = Component(EpicsSignal, ":close")
+    delay_s = 1.2
+    pss_state = FormattedComponent(EpicsSignalRO, "{self.state_pv}")
+
+    # strings the user will use
+    open_str = 'open'
+    close_str = 'close'
+
+    # pss_state PV values from EPICS
+    open_val = 1
+    close_val = 0
+
+    def __init__(self, prefix, state_pv, *args, **kwargs):
+        self.state_pv = state_pv
+        super().__init__(prefix, *args, **kwargs)
+
+    def open(self, timeout=10):
+        ophyd.status.wait(self.set(self.open_str), timeout=timeout)
+
+    def close(self, timeout=10):
+        ophyd.status.wait(self.set(self.close_str), timeout=timeout)
+
+    def set(self, value, **kwargs):
+        # first, validate the input value
+        acceptables = (self.close_str, self.open_str)
+        if value not in acceptables:
+            msg = "value should be one of " + " | ".join(acceptables)
+            msg += " : received " + str(value)
+            raise ValueError(msg)
+
+        command_signal = {
+            self.open_str: self.open_bit, 
+            self.close_str: self.close_bit
+        }[value]
+        expected_value = {
+            self.open_str: self.open_val, 
+            self.close_str: self.close_val
+        }[value]
+
+        working_status = DeviceStatus(self)
+
+        def shutter_cb(value, timestamp, **kwargs):
+            # APS shutter state PVs do not define strings, use numbers
+            #value = enums[int(value)]
+            value = int(value)
+            if value == expected_value:
+                self.pss_state.clear_sub(shutter_cb)
+                working_status._finished()
+
+        self.pss_state.subscribe(shutter_cb)
+        command_signal.set(1)
+        return working_status
+
+
 class AxisTunerException(ValueError): 
     """Exception during execution of `AxisTunerBase` subclass"""
     pass