Attributes of DATA Elements

Catalogues and Specifications Reference Manual

Data Set (DTSET) : Attributes of DATA Elements

Attributes of DATA Elements

Each DATA element has the following special attributes:

Data Key. An AVEVA E3D™ word which allows a specific DATA element to be referenced from within MODEL or DRAW using the Q PROP dkey command.

Property Type. This is a word attribute which defines what sort of property the DATA is providing.

DATA elements can be interpreted as references, text, reals and logical and this is primarily controlled by the pseudo attribute used to access the property. In most cases the setting of PTYPE is secondary to the enquiring pseudo attribute and the validation is done by ensuring the type of value returned (reference, text, real) matches the type of pseudo attribute.

However often PTYPE is set to a suitable value (e.g. REAL, DATA, TEXT, SPRF) compatible with the type but this is often not validated by the core system, only the application using the data.

PTYP can take any value (and often an application will rely on specific values). Those settings critical to the core system are those that distinguish which type of physical data is being supplied by REAL Data properties. The core system supported values are REAL, NONE, and any hash code for standard physical properties. Most significant of these are DIST and BORE but other common ones may be ANGL, MASS, etc.

When the data property is evaluated as a real value (when used in expressions etc) its physical dimension is checked against the DATA element's PTYP.

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If the dimensions agree or are compatible (DIST and BORE) this is OK.

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If the evaluated dimension is NONE then the value is assumed to be in current working units of the dimension, it is converted to database units internally, and no warning is issued.

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If PTYP is set to REAL or DATA or ANY then no warning will be issued even though there is scope for one to occur. This is because old databases may not have been populated with PTYP being set to any physical quantity.

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If PTYP is set to NONE, or to a mismatched dimension then a warning is raised.

The PTYP can be set to any generic quantity by supplying PTYP with a compound unit of the physical quantity (e.g. PTYP 1kg/m3/degC).

PTYP can be set to WORD for values of type WORD, which is a four character keyword commonly used for connection type information. WORD is a special case that should not be confused with the STRING data type. In order to set a default value for a WORD type property it is necessary to set the Default to a HASH value. This is done by entering an expression like ( HASH('ABCD') ) which sets the default WORD value to ABCD.

Data Title. A text string describing the property stored in the DATA.

Property. Any expression which defines a property of the item with which the dataset is associated.

Default Property Value. The value to be used if the true setting of the Property cannot be evaluated at any time. See Controlling the Detailed Checking Procedure.

Purpose. An AVEVA E3D™ word showing the purpose for which the stored property is relevant. For example, PARA (for catalogue parameters), DESP (for design parameters), DATA (for general properties).

Number. An integer which may be set to further categorise the specific property stored in the DATA. For example, the identifying number of a PARAM or DESPARAM.

Property Units. The units used when evaluating the Property value. This attribute is not used by the core system but by applications dependent on the data properties.

Real Property Flag. See Controlling the Detailed Checking Procedure.

The PPRO attribute is evaluated in response to the Q PROP... command in MODEL or DRAW. The parameters in the expression may not be defined until the item is added to the model. It can include any attributes which are valid for the design element, including user-defined attributes; for example:

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((:COST OF OWNER) * :LENGT).

The PPRO attribute can also be set to a parameterised expression which will be used in the definition of Pointsets and Geomsets. See Controlling the Detailed Checking Procedure.

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