LabVIEW如何减少下一代测试系统中的硬件过时4
DSSP Class Definition
DSSP父类定义有三种不同类型的函数:仅父类、公共类和基于度量的函数。DSSP父类，DSSP.Lvclass包含所有子类函数的超集，加上父类特有的一些函数。DSSP父类的单个子实例(例如AgSigGen.lvclass)必须包含公共DSSP函数和至少一个基于度量的函数。表1显示了不同的DSSP函数及其类别。
The DSSP parent class definition has three different types offunctions: parent-only, common, and measurement-based. The DSSP parent class,DSSP.lvclass, contains a superset of all the child class functions plus somefunctions unique to the parent. A single child instance of the parent DSSPclass (for example, Ag SigGen.lvclass) has to contain the common DSSP functionsand at least one of the measurement-based functions.Table 1 shows the differentDSSP functions and their categories.
Table 1. DSSP Function Categories
Table 2 shows which child classes implement parent DSSP functions.
Table 2. DSSP Function Locations
在示例实现中，只有DSSP父类包含测试工具中所需的所有函数。这是可能的，因为这个例子不是很复杂。对于更复杂的系统，您很可能希望拥有多个DSSP定义，以将每个DSSP中的函数数量控制在可管理的水平。
图7显示了“简单”实现，图8显示了“复杂”实现建议。
In the example implementation, only the parent DSSP class contains allof the functions that are needed in the test instrumentation. This is possiblebecause the example is not very complex. For a more complex system, you wouldmost likely want to have multiple DSSP definitions to keep the number offunctions in each one down to a manageable level.
Figure 7 shows the “simple” implementation and Figure 8 shows the“complex” implementation suggestion.
Themain difference between the two DSSP hierarchies is that the measurement-basedfunctions in the complex system are separated into another level of subclassesor virtual folders. This makes the development and maintenance even moremanageable for larger systems. Refer to Figure 9 to see that both the Ag SigGen and NI Sig Gen child classes implement the same functions because they arefilling the same role.
两个DSSP层次结构之间的主要区别是，复杂系统中基于度量的功能被分离到另一层子类或虚拟文件夹中。这使得大型系统的开发和维护更加易于管理。参考图9，可以看到Ag SigGen和NISig Gen子类都实现了相同的功能，因为它们填充了相同的角色。
Migrated System Configuration with New Hardware
Now update the system’s hardware. Figure 10 shows the updatedhardware.
使用新硬件迁移系统配置
现在更新系统硬件。图10显示了更新后的硬件。
Figure10. Updated System Hardware (no changes to DUT or fixture)
The system transitions from using four different instrument controlbuses (USB, LAN, GPIB, PXI) to using only PXI. Figure 11 shows the updatedsoftware.
系统从使用四种不同的仪表控制总线(USB、LAN、GPIB、PXI)过渡到仅使用PXI。图11显示了更新后的软件。
Figure11. Updated Software (provides same measurement result using new DSSP)
The blue box in Figure 11 shows that you had to develop and testthree new DSSP modules for the three new instruments. In this case, you did a one-to-onereplacement of instruments. Refer to figures 4 and 5 for a comparison to theoriginal system. The HAL prevented you from having to rewrite the testapplication.
图11中的蓝色方框显示您必须为三个新仪器开发和测试三个新的DSSP模块。在本例中，您进行了一对一的仪器更换。参考图4和图5了解与原始系统的比较。HAL使您不必重写测试应用程序。
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