Agilent Technologies E4406A VSA manual Addressing a Session, functions

	Programming Fundamentals
	C Programming Using VTL
vi	This is a pointer to the session identifier for this
	particular device session. This pointer will be used to
	identify this device session when using other VTL
	functions.

The following is an example of opening sessions with a GPIB multimeter and a GPIB-VXI scanner:

ViSession defaultRM, dmm, scanner;

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viOpenDefaultRM(&defaultRM);

viOpen (defaultRM, “GPIB0::22::INSTR”, VI_NULL, VI_NULL, &dmm);

viOpen (defaultRM, “GPIB-VXI0::24::INSTR”, VI_NULL, VI_NULL, &scanner);

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viClose (scanner); viClose (dmm); viClose(defaultRM);

The above function first opens a session with the default resource manager. The session returned from the resource manager and a device address is then used to open a session with the GPIB device at address

22.That session will now be identified as dmm when using other VTL functions. The session returned from the resource manager is then used again with another device address to open a session with the GPIB-VXI device at primary address 9 and VXI logical address 24. That session will now be identified as scanner when using other VTL functions. See the following section for information on addressing particular devices.

Addressing a Session

As seen in the previous section, the rsrcName parameter in the viOpen function is used to identify a specific device. This parameter is made up of the VTL interface name and the device address. The interface name is determined when you run the VTL Configuration Utility. This name is usually the interface type followed by a number. The following table illustrates the format of the rsrcName for the different interface types:

Interface	Syntax
VXI	VXI [board]::VXI logical address[::INSTR]
GPIB-VXI	GPIB-VXI [board]::VXI logical address[::INSTR]
GPIB	GPIB [board]::primary address[::secondary address][::INSTR]

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