Hi Khalid,
the driver-related parameters of the Packet Output block are specific for individual drivers and undocumented for programmatic use. That said, you have correctly identified the three related parameters - DrvName, DrvAddress, DrvOptions. Their meanings are like this:
DrvName is the type of the device. Typically, it is formed as the vendor name, then device model name or number, separated by slash. Spaces and other special characters are often replaced by substitute characters, e.g. underscores, to make the parameter a valid file name.
DrvAddress is the parameter that serves for distinguishing multiple devices of the same type. It can be some hardware address, local port number, or just the ordinal number (first, second, etc.), based on the type of the device. The pair of DrvName and DrvAddress uniquely identifies the device.
DrvOptions is the parameter that specifies various device-specific options and its format differs by device type, because each device requires a different set of parameters. In the case of the Kvaser CAN device, these are parameters like baud rates, message acceptance filter masks, and such.
The safest way how to set values of these parameters programmatically is to set them using the GUI first when developing your program, then read their values using get_param and use the exact same values when you are calling set_param from your program.
Please also note that the Packet Output block does have a popup selection of previously configured devices, so you may just try to use that. And if you really want to dig into the internals of the block parameter configuration implementation, please take a look at the rtblkgui and rtdrvgui functions. But please keep in mind that these functions implement undocumented internal functionality and their behavior or even their existence may change with any future release, without warning.
Good Luck, Jan
