A-3
A1
VXI-11.3 Instruments are addressed by their IP addresses. They then are con-
nected to by opening a socket connection to them. Finally a link is made to the
Instrument Interface inside the VXI-11.3 Instrument. Each VXI-11.3 Instru-
ment contains at least one Instrument Interface referred to as
inst0
. VXI-11.3
Instruments may have multiple Instrument Interfaces for sub-functions similar
to the dual primary or secondary address capability in GPIB devices. These
additional Instrument Interfaces are referred to as
inst1
to
instN.
The links are
created and destroyed by the
create_link
and
destroy_link
RPCs.
VXI-11.3 Instruments have a remote/local capability that is controlled by the
device_remote and device_local RPCs. This is equivalent to a GPIB device
operation with the REN line and the LLO and GTL commands.
VXI-11.3 Instruments have the ability to generate Service Requests similar
to SRQs in a GPIB device. The VXI-11.3 Instrument does this by acting as a
client and sending the
device_intr_srq
RPC to a service running on the same
computer with the client application. The service then handles the interrupt
and often generates a flag for the client indicating what device wanted service.
The user's client application can then Serial Poll the VXI-11.3 Instrument with
the
device_readstb
RPC to learn the cause of the Service request.
VXI-11.3 Instruments respond to a Selected Device Clear message when they
receive the
device_clear
RPC.
VXI-11.3 Instruments respond to a Device trigger message when they receive
the
device_trigger
RPC. The instrument's response is conditioned by the SCPI
INST and ABORT commands if they are supported by the Instrument.
VXI-11.3 Instruments have no equivalent functions for the following GPIB
interface messages: SPE, SPD, PPC and PPU.
A.1.1.2 Additional VXI-11.3 Functions
VXI-11.3 Instruments have three additional functions not related to the GPIB
bus or to the IEEE-488.1 Standard. They are:
The
device_abort
RPC causes the instrument to abort any operation associated
with the link that sent the RPC.
The device_lock and device_unlock RPCs causes the instrument to block ac-
cess to the instrument from other links while locked