Class definition

Line

Bases: PviObject

class representing a PVI Line

Typical usage example:

pviConnection = Connection()
line = Line( pviConnection.root, 'LNANSL', CD='LNANSL')
device = Device( line, 'TCP', CD='/IF=TcpIp' )

Source code in pvi\Line.py

class Line(PviObject):
    '''class representing a PVI Line

        Typical usage example:
        ```
        pviConnection = Connection()
        line = Line( pviConnection.root, 'LNANSL', CD='LNANSL')
        device = Device( line, 'TCP', CD='/IF=TcpIp' )
        ```
    '''
    def __init__( self, parent : PviObject, name : str, **objectDescriptor: Union[str,int, float]):
        '''
        Args: 
            parent : PVI connection's root object
            name : name of the line in PVI hierarchy, e.g. 'LNANSL'
            objectDescriptor: 
                ANSL : CD='LNANSL'  
                INA2000 : CD='LNINA2'  
                SNMP : CD='LNSNMP'

        '''
        if parent.type != T_POBJ_TYPE.POBJ_PVI:
            raise PviError(12009, self)         
        super().__init__( parent, T_POBJ_TYPE.POBJ_LINE, name, **objectDescriptor)

    def __repr__(self):
        return f"Line( name={self._name}, linkID={self._linkID} )"

descriptor: dict property

object descriptor example:

temperature = Variable( task1, 'gHeating.status.actTemp' )
...
print( "descriptor=", temperature.name)

results in:

descriptor= {'CD': 'gHeating.status.actTemp', 'RF': 0}

errorChanged: Callable property writable

callback for 'error changed'

It is advisable to always check the error status '0' before accessing an object.

Args:
    cb: callback( PviObject, int ) or callback( int )

typical example:

cpu = Cpu( device, 'myArsim', CD='/IP=127.0.0.1' )
...
def cpuErrorChanged( error : int ):
    if error != 0:
        raise PviError(error)

cpu.errorChanged = cpuErrorChanged

evmask: str property writable

event mask in link descriptor

"e": Change in error state "d": Data changes "f": Change to the data format "c": Change to the connection description "p": Progress information about active requests "s": Status changes "u": Change in the user tag string

externalObjects property

PviObject.externalObjects : list of dict get a list of external objects retrieved by POBJ_ACC_LIST_EXTERN

only available with ANSL, not with INA2000

example:

cpu = Cpu( device, 'myArsim', CD='/IP=127.0.0.1' )
...
print("external objects", cpu.externalObjects )

results in:

external objects [{'name': '$$sysconf', 'type': 'Module'}, {'name': '$arlogsys', 'type': 'Module'}
            ...... name': 'visvc', 'type': 'Module'}]

name: str property

hierarchical PVI object name

example:

name= @Pvi/LNANSL/TCP/myArsim/mainlogic/gHeating.status.actTemp

objectName: str property

object name

example:

temperature = Variable( task1, 'gHeating.status.actTemp' )
...
print( "oname=", temperature.name)

results in:

oname= gHeating.status.actTemp

status: dict property writable

PviObject.status read the object's status

example:

cpu = Cpu( device, 'myArsim', CD='/IP=127.0.0.1' )
task1 = Task( cpu, 'mainlogic')
temperature = Variable( task1, 'gHeating.status.actTemp' )
...
print("status=", cpu.status )

results in:

cpu.status= {'ST': 'WarmStart', 'RunState': 'RUN'}
task1.status {'ST': 'Running'}
temperature.status= {'ST': 'Var', 'SC': 'g'}

type: T_POBJ_TYPE property

object type

example:

temperature = Variable( task1, 'gHeating.status.actTemp' )
...
print( "type=", temperature.type)

results in:

type= T_POBJ_TYPE.POBJ_PVAR

userName: str property

user defined object name defaults to .objectName

userTag: str property writable

user tag

Typical usage example:

temperature = Variable( task1, name='gHeating.status.actTemp', UT="actual water temperature" )        

version: str property

PviObject.version read the object's version

__init__(parent, name, **objectDescriptor)

Parameters:

Name	Type	Description	Default
parent		PVI connection's root object	required
name		name of the line in PVI hierarchy, e.g. 'LNANSL'	required
objectDescriptor	Union[str, int, float]	ANSL : CD='LNANSL' INA2000 : CD='LNINA2' SNMP : CD='LNSNMP'	{}

Source code in pvi\Line.py

def __init__( self, parent : PviObject, name : str, **objectDescriptor: Union[str,int, float]):
    '''
    Args: 
        parent : PVI connection's root object
        name : name of the line in PVI hierarchy, e.g. 'LNANSL'
        objectDescriptor: 
            ANSL : CD='LNANSL'  
            INA2000 : CD='LNINA2'  
            SNMP : CD='LNSNMP'

    '''
    if parent.type != T_POBJ_TYPE.POBJ_PVI:
        raise PviError(12009, self)         
    super().__init__( parent, T_POBJ_TYPE.POBJ_LINE, name, **objectDescriptor)

kill()

PviObject.kill: kills this object this should be called when object is not beeing used anymore to save PVI resources

Source code in pvi\Object.py

def kill(self):
    '''
    PviObject.kill: kills this object
    this should be called when object is not beeing used anymore
    to save PVI resources
    '''
    if self._linkID != 0 and self._connection != None:

        self._connection._linkIDs.pop(self._linkID) # remove from linkIDs
        self._connection._pviObjects.remove(self) # remove from PviObjects
        self._result = PviXUnlink(self._hPvi, self._linkID)
        self._linkID = 0
        if self._result != 0 and self._result != 12045:
            raise PviError(self._result, self)