Rievtech PR-12 Series, Руководство пользователя и программиста

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6.18.2 Using parameters to call subroutine
Subroutine may contain the transfer parameters.The parameter is defined in the local
variable table of the subroutine.Parameters must have a symbol name (up to 23
characters), a variable type, and a data type.Each subroutine can be set up to 16
IN/OUT parameters.
Local variable table has 4 types of variables.They are IN, IN-OUT, OUT and TEMP.
Parameter type and description
IN
Parameters are transferred to the subroutine.If the parameter is a
direct address (e.g. VB10),the specified location value is transferred to the
subroutine.If the parameter is an indirect address (such as *AC1),the specified
location value is transferred to the subroutine.If the parameter is the data constant
(16#1234) or address (&VB100)
，
constants or addresses are transferred to the
subroutine.
IN_OUT
The specified location value is transferred to the subroutine.The
result of subroutine operation is transferred to the specified same location .This
parameter does not allow to use constants (such as 16#1234) and addresses
(e.g.&VB100).
OUT
The result of subroutine operation is transferred to the specified
location.Constants (such as 16#1234) and addresses (e.g. &VB100) are not allowed to
be used as output.
TEMP
Any local memory which is not used as a transfer parameter can ’ t be
used for temporary storage in subroutine.
Parameter data type Illustration
Boolean
It is used for unit input and output.
Byte, word, double word Input or output parameters without symbols.