As currently deployed at FERMI.

Makefile

+NAME = filterwheel-srv
+MAIN = FilterWheel.py
+
+DIRNAME = $(NAME:-srv=)
+MODNAME = $(MAIN:.py=)
+PY_FILES += $(wildcard src/*.py)
+
+default: bin ${PY_FILES}
+	@cp ${PY_FILES} bin/${DIRNAME}
+	@echo "#!/usr/bin/env python\nimport sys\nsys.path.append(sys.path[0]+'/${DIRNAME}')\nfrom ${MODNAME} import main\nif __name__ == '__main__':\n    main()\n" > bin/${NAME}
+	@chmod +x bin/${NAME} bin/${DIRNAME}/${MAIN}
+
+bin:
+	@test -d $@ || mkdir -p $@/${DIRNAME}
+
+clean:
+	@rm -fr bin/ src/*~
+
+.PHONY: clean

README.md

+# FilterWHeel Tango device server.
+
+The device server controls 7 filter circular holder and runs on top of a smaractmcs2 positioner. Allows for simple tagging and selection of deployed filters.
+

src/FilterWheel.py

+#!/usr/bin/env python
+#       "$Name:  $";
+#       "$Header:  $";
+#==================================================================
+#
+# file :        FilterWheel.py
+# description : PyTango utility device for SmarAct filter wheel that
+#               runs on top of the regular smaractmcs2-server.
+# project :     TANGO Device Server
+# $Author:      $ Elettra SPE (ex Elettra Sci.Comp.)
+# $Revision:    $ 0.1
+#
+#==================================================================
+#
+import sys
+import PyTango
+import numpy as np
+import warnings
+import time
+
+#==================================================================
+#   Device States Description:
+#
+#   DevState.INIT : Initialization
+#   DevState.ON : Standby/running
+#   DevState.MOVING : Smaract motors are moving
+#   DevState.ALARM : Incorrect position
+#   DevState.FAULT : Connection with motor failed
+#==================================================================
+class FilterWheel(PyTango.Device_4Impl):
+
+#------------------------------------------------------------------
+#    Device constructor
+#------------------------------------------------------------------
+    def __init__(self, cl, name):
+        print 'In Device constructor'
+        PyTango.Device_4Impl.__init__(self, cl, name)
+        FilterWheel.init_device(self)
+
+#------------------------------------------------------------------
+#    Device destructor
+#------------------------------------------------------------------
+    def delete_device(self):
+        print '[Device delete_device method] for device', str(self.get_name())
+        if self.wheel is not None:
+            del self.wheel
+
+#------------------------------------------------------------------
+#    Device initialization
+#------------------------------------------------------------------
+    def init_device(self):
+        print 'In init device'
+        self.set_state(PyTango.DevState.INIT)
+        self.set_status("Initializing device...")
+        self.get_device_properties(self.get_device_class())
+        #
+        self.last_status_update = 0
+        self.wheel_step = 360.0/7
+        self.wheel_alive = False
+        try:
+            # FilterWheelDevice is a SmarAct MCS2 Tango device.
+            self.wheel = PyTango.DeviceProxy(self.FilterWheelDevice)
+            self.wheel.ping()
+            self.wheel_alive = True
+        except PyTango.DevFailed:
+            exctype, value = sys.exc_info()[:2]
+            print "Failed with exception ! ", exctype
+            for err in value:
+                print " reason", err.reason
+                print " description", err.desc
+                print " origin", err.origin
+                print " severity", err.severity
+
+        self.attr_Filter1_read = ""
+        self.attr_Filter2_read = ""
+        self.attr_Filter3_read = ""
+        self.attr_Filter4_read = ""
+        self.attr_Filter5_read = ""
+        self.attr_Filter6_read = ""
+        self.attr_Filter7_read = ""
+        self.attr_CurrentPosition_read = 0.0
+        self.attr_CurrentIndex_read = 0
+        self.attr_CurrentFilter_read = ""
+        self.attr_MotorTitle_read = ""
+        if self.wheel_alive:            
+            self.set_state(PyTango.DevState.ON)
+        else:            
+            self.set_state(PyTango.DevState.FAULT)
+            self.set_status("Connection with device failed.")
+
+#------------------------------------------------------------------
+#    Always excuted hook method
+#------------------------------------------------------------------
+    def always_executed_hook(self):
+        # print "In ", self.get_name(), "::always_executed_hook()"
+        if time.time()-self.last_status_update > 0.2:
+            self.update_state_and_status()
+            self.last_status_update = time.time()
+
+    def update_state_and_status(self):
+        try:
+            wheel_state = self.wheel.State()
+            wheel_status = self.wheel.Status()
+            if wheel_state == PyTango.DevState.ON:
+                selected_filter = self.selected_filter()
+                if selected_filter is not None:
+                    self.attr_CurrentIndex_read = selected_filter
+                    self.attr_CurrentFilter_read = eval("self.attr_Filter"+str(selected_filter)+"_read")
+                    self.set_status(self.attr_CurrentFilter_read + " selected")
+                    self.set_state(PyTango.DevState.ON)
+                else:
+                    self.attr_CurrentIndex_read = 0
+                    self.set_status("No filter selected")
+                    self.set_state(PyTango.DevState.ALARM)
+            elif wheel_state == PyTango.DevState.MOVING:
+                self.set_state(PyTango.DevState.MOVING)
+                self.set_status("Wheel moving")
+            else:
+                self.set_state(wheel_state)
+                self.set_status(wheel_status)
+        except PyTango.DevFailed:
+            exctype, value = sys.exc_info()[:2]
+            print "Failed with exception ! ", exctype
+            self.set_state(PyTango.DevState.FAULT)
+            self.set_status("Connection with device failed.")
+
+    def selected_filter(self):
+        selected_wheel = None
+        try:
+            pos = self.wheel.Position
+            self.debug_stream("Current motor position "+str(pos))
+            self.attr_CurrentPosition_read = pos
+            if pos<-2.0:
+                pos += 360.0
+            if abs(pos/self.wheel_step - round(pos/self.wheel_step)) < 0.1:
+                selected_wheel = int(abs(round(pos/self.wheel_step)))+1
+        except PyTango.DevFailed:
+            exctype, value = sys.exc_info()[:2]
+            print "Failed with exception ! ", exctype
+        self.debug_stream("Selected filter "+str(selected_wheel))
+        return selected_wheel
+
+    def select_filter(self, filter_number):
+        if filter_number <=4:
+            pos = round(float(filter_number-1) * self.wheel_step, 4)
+        else:
+            pos = round(float(filter_number-1) * self.wheel_step - 360.0, 4)
+        try:
+            self.wheel.write_attribute("Position", pos)
+        except PyTango.DevFailed:
+            exctype, value = sys.exc_info()[:2]
+            print "Failed with exception ! ", exctype
+        
+#==================================================================
+#
+#    FilterWheel read/write attribute methods
+#
+#==================================================================
+
+    def read_CurrentPosition(self, attr):
+        attr.set_value(self.attr_CurrentPosition_read)
+
+    def read_CurrentIndex(self, attr):
+        attr.set_value(self.attr_CurrentIndex_read)
+
+    def read_CurrentFilter(self, attr):
+        attr.set_value(self.attr_CurrentFilter_read)
+
+    def read_Filter1(self, attr):
+        attr.set_value(self.attr_Filter1_read)
+
+    def write_Filter1(self, attr):
+        data = attr.get_write_value()
+        self.attr_Filter1_read = data
+
+    def read_Filter2(self, attr):
+        attr.set_value(self.attr_Filter2_read)
+
+    def write_Filter2(self, attr):
+        data = attr.get_write_value()
+        self.attr_Filter2_read = data
+
+    def read_Filter3(self, attr):
+        attr.set_value(self.attr_Filter3_read)
+
+    def write_Filter3(self, attr):
+        data = attr.get_write_value()
+        self.attr_Filter3_read = data        
+
+    def read_Filter4(self, attr):
+        attr.set_value(self.attr_Filter4_read)
+
+    def write_Filter4(self, attr):
+        data = attr.get_write_value()
+        self.attr_Filter4_read = data
+
+    def read_Filter5(self, attr):
+        attr.set_value(self.attr_Filter5_read)
+
+    def write_Filter5(self, attr):
+        data = attr.get_write_value()
+        self.attr_Filter5_read = data
+
+    def read_Filter6(self, attr):
+        attr.set_value(self.attr_Filter6_read)
+
+    def write_Filter6(self, attr):
+        data = attr.get_write_value()
+        self.attr_Filter6_read = data
+
+    def read_Filter7(self, attr):
+        attr.set_value(self.attr_Filter7_read)
+
+    def write_Filter7(self, attr):
+        data = attr.get_write_value()
+        self.attr_Filter7_read = data
+
+    def read_MotorTitle(self, attr):
+        attr.set_value(self.attr_MotorTitle_read)
+
+    def write_MotorTitle(self, attr):
+        data = attr.get_write_value()
+        self.attr_MotorTitle_read = data        
+        
+#==================================================================
+#
+#    FilterWheel command methods
+# 
+#==================================================================
+
+    def SetClear(self):
+        # self.debug_stream("In SetClear()")
+        self.select_filter(1)
+        self.debug_stream("Selecting filter 1 (Clear or no-filter)")
+
+    def is_SetClear_allowed(self):
+        return self.get_state() in (PyTango.DevState.ON, PyTango.DevState.ALARM,)         
+        
+    def SetFilter(self, filter_number):
+        # self.debug_stream("In SetFilter()")
+        if 1 <= filter_number <= 7:
+            self.select_filter(filter_number)
+            self.debug_stream("Selecting filter "+str(filter_number))
+        else:
+            self.error_stream("Invalid filter number.")
+            PyTango.Except.throw_exception("SetFilter Error", "Filter number out of range", "SetFilter()") 
+
+    def is_SetFilter_allowed(self):
+        return self.get_state() in (PyTango.DevState.ON, PyTango.DevState.ALARM,) 
+
+#==================================================================
+#
+#    FilterWheelClass class definition
+#
+#==================================================================
+class FilterWheelClass(PyTango.DeviceClass):
+
+    #    Class Properties
+    class_property_list = {
+        }
+
+    #    Device Properties
+    device_property_list = {
+        'FilterWheelDevice':
+            [PyTango.DevString,
+            "Tango Device that controls the FilterWheel motor.",
+            []],
+        }
+
+    # Command definitions
+    cmd_list = {
+        'SetClear':
+            [[PyTango.DevVoid, "none"],
+            [PyTango.DevVoid, "none"]],
+        'SetFilter':
+            [[PyTango.DevShort, "Filter number 1-7"],
+            [PyTango.DevVoid, "none"]],
+        }
+
+    #    Attribute definitions
+    attr_list = {
+        'CurrentPosition':
+            [[PyTango.DevFloat,
+            PyTango.SCALAR,
+            PyTango.READ],
+            {
+                'description':"Currently selected filter",
+                'Memorized': "False",
+            }],
+        'CurrentIndex':
+            [[PyTango.DevShort,
+            PyTango.SCALAR,
+            PyTango.READ],
+            {
+                'description':"Currently selected filter index (1-7), 0 if None",
+                'Memorized': "False",
+            }],
+        'CurrentFilter':
+            [[PyTango.DevString,
+            PyTango.SCALAR,
+            PyTango.READ],
+            {
+                'description':"Currently selected filter",
+                'Memorized': "False",
+            }],
+        'Filter1':
+            [[PyTango.DevString,
+            PyTango.SCALAR,
+            PyTango.READ_WRITE],
+            {
+                'description':"Filter at position 1",
+                'Memorized': "True",
+            }],
+        'Filter2':
+            [[PyTango.DevString,
+            PyTango.SCALAR,
+            PyTango.READ_WRITE],
+            {
+                'description':"Filter at position 2",
+                'Memorized': "True",
+            }],  
+        'Filter3':
+            [[PyTango.DevString,
+            PyTango.SCALAR,
+            PyTango.READ_WRITE],
+            {
+                'description':"Filter at position 3",
+                'Memorized': "True",
+            }],  
+        'Filter4':
+            [[PyTango.DevString,
+            PyTango.SCALAR,
+            PyTango.READ_WRITE],
+            {
+                'description':"Filter at position 4",
+                'Memorized': "True",
+            }],  
+        'Filter5':
+            [[PyTango.DevString,
+            PyTango.SCALAR,
+            PyTango.READ_WRITE],
+            {
+                'description':"Filter at position 5",
+                'Memorized': "True",
+            }],  
+        'Filter6':
+            [[PyTango.DevString,
+            PyTango.SCALAR,
+            PyTango.READ_WRITE],
+            {
+                'description':"Filter at position 6",
+                'Memorized': "True",
+            }],  
+        'Filter7':
+            [[PyTango.DevString,
+            PyTango.SCALAR,
+            PyTango.READ_WRITE],
+            {
+                'description':"Filter at position 7",
+                'Memorized': "True",
+            }],  
+        'MotorTitle':
+            [[PyTango.DevString,
+            PyTango.SCALAR,
+            PyTango.READ_WRITE],
+            {
+                'description': "Motor's given name for the GUI's title label.",
+                'memorized':"true",
+            }],
+        }
+
+#------------------------------------------------------------------
+#    FilterWheelClass Constructor
+#------------------------------------------------------------------
+    def __init__(self, name):
+        print 'In FilterWheelClass constructor'
+        PyTango.DeviceClass.__init__(self, name)
+        self.set_type(name)
+
+#==================================================================
+#
+#    FilterWheel class main method
+#
+#==================================================================
+if __name__ == '__main__':
+    try:
+        py = PyTango.Util(sys.argv)
+        py.add_TgClass(FilterWheelClass, FilterWheel, 'FilterWheel')
+
+        U = PyTango.Util.instance()
+        U.server_init()
+        U.server_run()
+
+    except PyTango.DevFailed, e:
+        print '-------> Received a DevFailed exception:', e
+    except Exception, e:
+        print '-------> An unforeseen exception occured....', e