VisualApplets
Operator Reference

Library Parameters provides several major advantages for the parametrization of designs during design time AND during runtime:

The good thing about the parameters library is that you can set up connections (nets or chains) between parameter values in your design without actually touching the data flow structure of the design.

Library Parameters contains seven reference operators and four translation operators. Find more information about both types of operators below.

You find example designs using the operators of the Parameters Library in your VisualApplets installation: <installation_directory>\VisualApplets\Examples\AdvancedVAFunctions\Parameters Library.

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The Reference Operators

The Reference operators of the Parameters library allow a 1:1 mapping of an operator parameter to the map parameter Value (or Field) of the reference operator. You specify the referenced parameter (path and name) in parameter "Reference".

You can define a target within the design hierarchy where the referenced parameter will be visible and accessible. The target is defined by two parameters: "DisplayHierarchy" and "DisplayName". In "DisplayHierarchy" you address a hierarchical box within the same process the reference operator itself is located in. In parameter "DisplayName" you set up the name for the target parameter. If "DisplayHierarchy" and "DisplayName" are both set, the parameter defined by "DisplayName" will be available in the hierarchical box addressed by "DisplayHierarchy". If "DisplayName" is empty, no parameter is created. If "DisplayName" is set, but "DisplayHierarchy" is empty, the parameter defined by "DisplayName" is added to the parent hierarchy (i.e., the hierarchical box the reference operator itself is located in).

This allows you to make a parameter of your design available on any hierarchical level (of the design) you want. For example, you can make the parameters of modules within a protected hierarchical box available for parametrization directly under the properties of the protected hierarchical box itself.

Mapped parameters can be referenced themselves. Thus, you can reference either the content of parameter Value in a reference operator, or reference the parameter you have defined in the parameters "DisplayName" and "DisplayHierarchy". This is especially important when protected hierarchical boxes are built up out of other protected hierarchical boxes.

To set up map parameters, you simply proceed 2 to 3 steps:

All map parameters are treated as normal parameters by the environment. You can access them via the Framegrabber API or the Framegrabber SDK tools (microDiagnostics and microDisplay) the same way you access "original" operator parameters.

Each instance of a reference operator allows to set up an 1:1 relation between the value of any parameter in your design and the map parameter (parameter Value) of the reference operator instance.

Data types supported by reference operators:

To create map parameters, you first need to instantiate one reference operator. For each possible data type, you have one reference operator available:

Procedure for creating map values with Reference Operators:

In the example below, an instance of the operator IntParamReference with the name Reference Operator Example connects to the parameter YLength in module Buffer. In this example, both modules (Reference Operator Example and Buffer) are located on the same hierarchical level.

Path to referenced parameter:

Referenced parameter:

In our example, the value of parameter YLength in operator Buffer is now also available in parameter Value of the reference operator instance:

With parameter Value in your reference operator, you can do many things.

You can, for example, make the value you have in parameter Value available in yet another module (operator instance or hierarchical box) anyplace in your design. To do so:

In our example, parameter Value of the reference operator instance is connected to a new parameter ConnectionToYLengthInModuleBuffer of module ModuleWithConnectedParameter :

If parameter Activate is set to "Yes", after clicking the Apply button, the new parameter is displayed with the correct value in the connected module:

Thus, the new parameter ConnectionToYLengthInModuleBuffer of module ModuleWithConnectedParameter has the same value as parameter YLength of module Buffer.

The mapping is done by the reference operator instance.

If the connected parameters of any of the three modules is reset, the value is reset in all other modules, too:

Hierarchical Boxes:

The Reference operators of the Parameters library allow you to make a parameter of your design available on any hierarchical level (of the design) you want. This is especially helpful if you want to allow parametrization of parameters nestled deeply within protected hierarchical boxes during runtime (i.e., if you want to make them available as dynamic write parameters). To allow easy parametrization of hierarchical boxes, hierarchical boxes can carry parameters now (as parameters in the Properties of the hierarchical box itself).

The Reference operators allow to set paths from the surface of a hierarchical box (Properties of the hierarchical box) to specific parameters which may be deeply embedded. This way, even parameters in protected hierarchical boxes (or in protected hierarchical boxes that are nestled in other protected hierarchical boxes) can be set and reset during runtime, since their parametrization interface is lifted up in the hierarchy to a hierarchical level that is not access restricted.

Mapped parameters can be referenced themselves. Thus, you can reference either the content of parameter Value (or Field) in a reference operator, or reference the parameter you have defined in the parameters DisplayName and DisplayHierarchy of the reference operator. This is especially important when protected hierarchical boxes are built up out of other protected hierarchical boxes.

In our example, this means you can reference parameter Value in module ReferenceOperatorExample as well as parameter ConnectionToYLengthInModuleBuffer in module ModuleWithConnectedParameter.

Reference to parameter Value of reference operator instance ReferenceOperatorExample:

Reference to parameter ConnectionToYLengthInModuleBuffer of module ModuleWithConnectedParameter:

Via the six available reference operators, all data types are provided that can occur as parameter values in protected hierarchical boxes.

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The Translation Operators

The translation operators of the parameters library allow translated access to parameters of one or several other operators.

For calculation, you define formulas. The syntax for these formulas complies to GenICam API version 2.0 and is described below.

Read Action:

In parameter ReadAction, you define what happens for a read access to parameter Value of the translation operator.

One of the main differences to the reference operators is that translation operators don't simply hold a value. Instead, the value of parameter Value is calculated out of a formula. This formula you define in parameter ReadAction.

As soon as there happens a read access to parameter Value, the formula you defined in ReadAction is carried out and the result is forwarded to the element asking for the value.

The formula can contain values of operator parameters anywhere in the design. As soon as one of these values changes, the calculation of translation operator's parameter Value will end up with a new result (different to the value parameter Value held before).

The formula can not only incorporate the values of parameters, but also specific properties of parameters, such as minimal value, maximal value, step size, or the numerical value of enumeration items.

Write Action

In parameter WriteAction, you define what happens during a write access to parameter Value of the translation operator.

In contrast to the reference operators you do not simply forward the value of parameter Value to another parameter in the design. Instead, the value of parameter Value is used for a set of write actions you define in parameter WriteAction of the translation operator. Write actions are composed of one or several equations. With the left side of these equations you define which parameter of which operator receives the result of the calculation. If you define more than one equation separate the equations via semicolon.

As soon as the there happens a write access to parameter Value, the formula(s) on the right side of the equations you defined in parameter WriteAction is/are carried out and the result(s) is/are forwarded to the parameters specified on the left side of the equations.

The formula can refer to values of operator parameters anywhere in the design. As soon as one of these values changes, the calculation results will differ when you re-write the same value as before to the Value parameter.

The formula can not only incorporate the values of parameters, but also specific properties of parameters, such as minimal value, maximal value, step size, or the numerical value of enumeration items.

Data Types:

The operator you select defines the data type of its parameter Value, i.e.:

Operator IntParamTranslator -> integer value

Operator FloatParamTranslator -> float integer value

Operator EnumParamTranslator -> value of an enumeration

However, although the operator defines the type of its parameter Value, it does not restrict the data types of the parameters which are accessed during the write or read operations. For example, operator IntParamTranslator defines that its parameter Value is of type integer; but the formulas defined in the operator can contain access to, e.g., parameters of type double.

Formulas for Calculation of Value Range

You can also add formulas to calculate the current value range of parameter Value. You define the according formulas in the parameters RangeFrom, RangeTo, and RangeIncrement (step size).

The formulas can contain values of module parameters anywhere in the design, as well as specific properties of these parameters, such as minimal value, maximal value, step size, or the numerical value of enumeration items.

The following list summarizes all Operators of Library Parameters