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The Transfer Variable Node identifies a numeric variable that is computed within the Work Flow as a function of input and output variables. The input and output variables must be known inside the transfer variable subsystem. In order to be known these variables must belong to the same subsystem as the transfer variable, or they must be published by their enclosing subsystem. Any design for which one or more transfer variable does not hold a legal numeric value is considered invalid.
Configuring a transfer variable node requires setting three parameters:
Name: the name that will be used throughout modeFRONTIER to identify the variable. The name must be unique within the set of node names, and must follow the guidelines for node names. The name for a transfer variable should be selected carefully at the beginning of the project, as changing it later on will cause the invalidation of all input files containing the variable. In contrast, expressions based on the node (within switch conditions) will be automatically updated.
Description: the node description will appear as tooltip when the mouse stop over the node in the Work Flow canvas.
User Expression: the expression that must be used to compute the value for this variable. The expression must be a mathematical function of input and output variables. It can be either inserted manually, or the Expression Editor can be invoked by clicking on the icon next to the expression field.
Format: the numeric format that will be used in the various tables to display the value for the transfer variable. The legal syntax for this parameter is described elsewhere (see Section 4.2.7, "Number Format Legal Syntax").
This node cannot be manually connected to any input. However, the nodes for the variables that are used within the user expression are automatically connected to this node.
The Transfer variable node output connector can be connected to one or more data input connectors. They must belong to a node of the following types:
In the last seven cases, the rule to be used to pass the value of the transfer variable to the receiving node must be specified through the properties dialog for the connected node.
Two error messages can be associated with a transfer variable node:
| 110 | MISSING EXPRESSION | No user expression has been provided |
| -1 | [An expression parser error] | The user expression provided is not a legal expression, and cannot be evaluated properly. The actual message should help the user understand where the problem lies. |
