Setting value of dynamic attributes on initialization

# 2 years ago
dschick	Hi all, I have written a PyTango DS which creates a list of boolean dynamic attributes for a DIO DAQ device. I am currently struggling with the situation, that all writable attributes are initialized as True and that this value is also not written to the DAQ which means, that the DO are actually all False, while Jive indicates a True after startup. So my question is, how can I set the value of a dynamic attribute on initializaton? Many thanks in advance! Daniel Edited 2 years ago

# 2 years ago

Hi all,

I have written a PyTango DS which creates a list of boolean dynamic attributes for a DIO DAQ device.

I am currently struggling with the situation, that all writable attributes are initialized as True and that this value is also not written to the DAQ which means, that the DO are actually all False, while Jive indicates a True after startup.

So my question is, how can I set the value of a dynamic attribute on initializaton?

Many thanks in advance!

Daniel

Edited 2 years ago

# 2 years ago
yamatveyev	Hi, Daniel I am not sure I correctly understand your quiestion. Why don`t you just call read function by yourself after add_attribute method? E.g. class TestDevice(Device): def __init__(self, args, kwargs): super(TestDevice, self).__init__(args, **kwargs) self._dyn_attr_value = None def initialize_dynamic_attributes(self): attr = attribute( name="dyn_attr", dtype=dtype, max_dim_x=10, access=AttrWriteType.READ_WRITE, fget=self.read_attr, fset=self.write_attr, ) self.add_attribute(attr) # and here we do initialisation self.read_attr() def read_attr(self, attr): self._dyn_attr_value = some_function_to_read_attribute() attr.set_value(self._dyn_attr_value ) def write_attr(self, attr): self._dyn_attr_value = attr.get_write_value() some_function_to_set_attribute(self._dyn_attr_value) Or did I undestand something wrong? Edited 2 years ago

# 2 years ago

yamatveyev

Hi, Daniel

I am not sure I correctly understand your quiestion. Why don`t you just call read function by yourself after add_attribute method?

E.g.


   class TestDevice(Device):

        def __init__(self, *args, **kwargs):
            super(TestDevice, self).__init__(*args, **kwargs)
            self._dyn_attr_value = None

        def initialize_dynamic_attributes(self):
            attr = attribute(
                name="dyn_attr",
                dtype=dtype,
                max_dim_x=10,
                access=AttrWriteType.READ_WRITE,
                fget=self.read_attr,
                fset=self.write_attr,
            )
            self.add_attribute(attr)

            # and here we do initialisation
            self.read_attr()

        def read_attr(self, attr):
            self._dyn_attr_value = some_function_to_read_attribute()
            attr.set_value(self._dyn_attr_value )

        def write_attr(self, attr):
            self._dyn_attr_value = attr.get_write_value()
            some_function_to_set_attribute(self._dyn_attr_value)

Or did I undestand something wrong?

Edited 2 years ago

# 2 years ago
sanin	Hi, Daniel If you want the real DO value to be available after attribute creation, use set_write_value() function. Something like during attribute creation procedure: attr = attribute(name="dyn_attr_name", ..other_pars) self.add_attribute(attr) v = read_real_attribute value() self.dyn_attr_name.set_write_value(v)