VTI Instruments EX1401, User Manual

Page: 81 / 114

www.vtiinstruments.com
EX1401 Instrument Drivers 81
M
ULTIPLE
I
NSTRUMENTS
I
NITIALIZING WITH
M
ULTIPLE
I
NSTRUMENTS
Unlike many typical instrument drivers, the Digitizer drivers allow multiple EX1401 devices and
other EMX devices to be controlled as if they were a single, collective instrument. The user can
initialize a single driver for two EX1401 devices and treat them as a single, 32-channel instrument
instead of creating two driver sessions with 16 input channels each. Multiple types of device can
also be included in the driver session.
When initializing the driver session, the resource name is passed as an argument to the Initialize
method that specifies which instruments will communicate. The resource name has the following
syntax:
<address 1>[ ::<slot 1>,<slot 2>,..,slot N> ] | <address 2> [
::<slot 1>,<slot 2>,…,<slot M> ] | …
Where:
<address x>
is the IP address or host name of the EX1401 or EMX-2500 controller (of the PXIe
chassis, where EMX series cards are installed)
<slot x>
is the slot number identifier of the instrument in a chassis. The slot number identifier is
a string such as “slot0_5” which indicates the 5
th
slot of the first chassis controlled by an EMX-
2500. An identifier such as “slot1_6” indicates the 6
th
slot of the 2
nd
chassis extended by a bus
extender. (Bus extenders are not supported by all devices.)
The slot numbers are optional. When no slot numbers are specified, all supported instruments within
the chassis will be used. The slot number for all EX1401 instruments is “inst0”, but this can always
be safely omitted.
When connecting to more than one EX1401 or EMX-2500 controller, the addresses must be
concatenated with the “|” (pipe) character.
The resource string to connect to a particular device can be found on the Index web page (see Index
in Section 4 .
M
ULTIPLE
I
NSTRUMENT
C
OORDINATION
When the driver session contains multiple EX1401 and EMX devices, the Sync and
ReferenceOscillator interfaces must be used to synchronize the sampling clocks and trigger models
on each device to have the best sample-to-sample alignment during measurements.