Agilent Technologies ESA-E Series Programmer's Manual page 64

viOpenDefaultRM (sesn);
viOpen (sesn, rsrcName, accessMode, timeout, vi);
The session returned from viOpenDefaultRM must be used in the sesn
parameter of the viOpen function. The viOpen function then uses that
session and the device address specified in the (resource name)
parameter to open a device session. The vi parameter in viOpen returns
a session identifier that can be used with other VTL functions.
Your program may have several sessions open at the same time by
creating multiple session identifiers by calling the viOpen function
multiple times.
The following summarizes the parameters in the previous function
calls:
sesn This is a session returned from the viOpenDefaultRM
function that identifies the resource manager session.
rsrcName This is a unique symbolic name of the device (device
address).
accessMode This parameter is not used for VTL. Use VI_NULL.
timeout This parameter is not used for VTL. Use VI_NULL.
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 an HP-IB
multimeter and an HP-IB/VXI scanner:
ViSession defaultRM, dmm, scanner;
.
.
viOpenDefaultRM(&defaultRM);
viOpen(defaultRM, "GPIB0::22::INSTR", VI_NULL,
VI_NULL, &dmm);
viOpen(defaultRM, "GPIB-VXI0::24::INSTR", VI_NULL,
VI_NULL, &scanner);
.
.
viClose(scanner);
viClose(dmm);
viClose(defaultRM);
Chapter 3
Programming Examples
C Programming Examples using VTL
3-9