R&S AFQ100A
Hardware Interfaces
1401.3084.32
8.7
E-3
A VXI-11 link between a controller and an instrument uses three channels: a core, abort and interrupt
channel. Instrument control is mainly performed on the core channel (program, response and low-level
control messages). The abort channel is used for immediate abort of the core channel; the interrupt
channel transmits spontaneous service requests of the instrument. Link setup itself is very complex. For
more details refer to the VXI-11 specification ("TCP/IP Instrument Protocol Specification VXI-11,
Revision 1.0 VMEbus Extensions for Instrumentation, VXIbus", and "TCP/IP-IEEE 488.2 Instrument
Interface Specification VXI-11.3, Draft 0.3 VMEbus Extensions for Instrumentation, VXIbus").
Instrument
Controller
Interrupt channel
(Service request)
Abort channel
(abort)
Core channel
(program, response,
control messages )
Fig. 8-3
VXI-11 channels between instrument and controller
The number of controllers that can address an instrument is practically unlimited in the network. In the
instrument, the individual controllers are clearly distinguished. This distinction continues up to the
application level in the controller, i.e. two applications on a PC are identified by the instrument as two
different controllers.
Instrument
Controller
Controller
Controller
Fig. 8-4
Remote control via LAN from several controllers
The controllers can lock and unlock the instrument for exclusive access. This regulates access to the
instrument of several controllers.
