Catalogues and Specifications
Reference Manual
Catalogue Database Structure
:
Parameters
: Physical Dimension of Parameters
Physical Dimension of Parameters
Parameters can be defined, either singularly or sequentially in the parameter list with a unit qualifier. This makes sure that the value of the parameter is converted to the relevant database value, for example:
PARAM 5 90degrees 10inch
Will be stored as 5,90,254 in the database and these values will be used in expressions using the parameters.
The unit qualifier also defines the type of physical quantity of the parameter (i.e. its physical dimension) and this is also stored so in the above example. Hence the system knows that the dimensions of the 3 parameters are:
NONE, DIST, and ANGL
and it will use this information when and wherever the parameters are used; for example when querying or listing the parameters, and in particular, in any assignments or expressions that use the parameters. If the dimensioned parameters are misused in expressions
Param[3] + param[2]
Sine ( param[2] )
or when setting attributes of different dimension e.g.
PYLEN ( ( PARAM[3] + 4 )
Warnings and/or errors will be raised.
In a dimensionally correct form of the above example
PYLEN = (PARAM[2] + 4 )
the 4 would be interpreted as a distance (because it is being added to a distance (param(2) ) ) and so the 4 would be treated as 4 current working distance units which may be inches or mm at the time, i.e. either 101.6mm or 4mm.
The dimension of the parameter is transient and is reset and changed as and when the parameter is redefined.
1974 to current year.
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