VWorks plugin fundamentals

The rest of this chapter provides the following basic information:

•	An explanation of how information is exchanged between VWorks software and the plugin

•	Definitions of the COM interfaces used for creating VWorks plugins

Information exchange

Information is exchanged between VWorks software and a plugin by passing XML metadata strings as parameters in COM interface methods.

To work with VWorks software, a plugin must do the following:

•	Parse XML strings that VWorks software provides as input parameters in the COM interface methods

•	Construct well-formed XML strings as output parameters that are returned to VWorks software by the COM interface methods

You can write your own utilities to build the XML strings, or you can use the Microsoft COM implementation of the XML Document Object Model (DOM) classes, which enables you to construct XML documents in memory. For more information about DOM, visit the Microsoft Developer Center at http://windowssdk.msdn.microsoft.com/en-us/library/ms766487.aspx.

IMPORTANT All XML strings must be well-formed, or the plugin will fail to load when VWorks software is started.

Interfaces overview

VWorks software defines the COM interfaces that are listed in the following table. All VWorks device driver plugins must implement the IWorksDriver, IControllerClient, and IWorksDiags interfaces. The remaining interfaces are optional and can be implemented by the plugins that require them.

 

Interface name	Purpose	Type library	Req’d
“IBCRDriver interface”	VWorks plugins that control barcode readers must implement the IBCRDriver interface.	IWorksDriver.dll	No
“IControllerClient interface”	All VWorks plugins must implement the IControllerClient interface to get a pointer from VWorks software to the IWorksController interface.	IWorksDriver.dll	Yes
“IIODriver interface”	VWorks plugins that manage I/O signals must implement the IIODriver interface.	IWorksDriver.dll	No
“ILabelerDriver interface”	VWorks plugins that perform labware-labeling tasks must implement the ILabelerDriver interface.	IWorksDriver.dll	No
“ILiddingDriver interface”	VWorks plugins that perform delidding and relidding operations must implement the ILiddingDriver interface.	IWorksDriver.dll	No
“IMeasurementDriver interface”	VWorks plugins that return measurement values and monitor device measurements must implement the IMeasurementDriver interface.	IWorksDriver.dll	No
“IPipetteDriver interface”	Reserved for internal use. VWorks plugins should not implement the IPipetteDriver interface.	IWorksDriver.dll	Not used
“IRobotDriver interface”	VWorks plugins that use robots to move labware must implement the IRobotDriver interface.	IWorksDriver.dll	No
“ISpinDriver interface”	VWorks plugins that perform Centrifuge tasks must implement the ISpinDriver interface.	IWorksDriver.dll	No
“IStackerDriver interface”	VWorks plugins that control labware stacker devices must implement the IStackerDriver interface.	IWorksDriver.dll	No
“IStorageDriver interface”	VWorks plugins that control labware storage devices must implement the IStorageDriver interface.	IWorksDriver.dll	No
“IVHooks interface”	VWorks plugins that want to act on events in VWorks software must implement the IVHooks interface.	VHooksInterface.dll	No
“IWorksAsyncDriver interface”	VWorks plugins that perform simultaneous tasks must implement the IWorksAsyncDriver interface.	IWorksDriver.dll	No
“IWorksController interface”	VWorks software implements the IWorksController interface. Plugins must call IWorksController methods to do the following: • Notify VWorks software about user activities • Write messages to the Main Log • Communicate with another plugin using VWorks software as the intermediary • Tell VWorks software to perform certain actions • Request information from VWorks software • Return information to VWorks software	IWorksDriver.dll	No
“IWorksDiags interface”	To open diagnostics dialog boxes in VWorks software, all VWorks device driver plugins must implement the IWorksDiags interface.	IWorksDriver.dll	Yes
“IWorksDriver interface”	All VWorks device driver plugins must implement the IWorksDriver interface. VWorks software calls IWorksDriver methods to do the following: • Tell the plugin to initialize or close a device • Notify the plugin of a user action • Tell the plugin to execute a task • Get an icon or description of a device or task from the plugin • Manage labware-handling processes • Get the description of the error that occurred when the plugin returned an error code • Log errors and warnings reported by the plugin during protocol compilation • Provide the means for two plugins to communicate with each other	IWorksDriver.dll	Yes
“IWorksProfiles interface”	To export nonstandard registry and file data associated with a profile, VWorks plugins must implement the IWorksProfiles interface.	IWorksDriver.dll	No