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ICMP Ping Server
The unit contains an ICMP server allowing the instrument to be ‘pinged’ via either its host name
or IP address.
VXI-11 Discovery Protocol
The instrument has very limited support of VXI-11 which is sufficient for the discovery protocol
and no more.
The instrument implements a Sun RPC Port-mapper on TCP port 111 and UDP port 111 as
defined in RPC1183. The calls supported are: NULL, GET PORT and DUMP.
On TCP port 1024 a very simple VXI-11 protocol is implemented sufficient only for instrument
discovery. This implements the following calls: CREATE LINK, DEVICE_WRITE,
DEVICE_READ and DESTROY_LINK.
Once a link has been created anything written to the device is ignored and any read from the
device returns the identification string as would be expected from a “*IDN?” of the form
‘Manufacturer,Model,Serial No.,X.xx – Y.yy’
for example
THURLBY THANDAR, QPX1200, 279730, 3.00 – 1.00
where ‘X.xx’ is the revision of the main firmware and ‘Y.yy’ is the revision of the interface
firmware. Interface firmware is user field updateable via the USB port.
mDNS and DNS-SD Support
Multicast DNS provides DNS services even on networks without a central DNS server (or DHCP
server). This simplifies the setting up of a simple LAN using meaningful hostnames instead of a
raw IP address. With service discovery it becomes straightforward for the device to be
discovered and the services it provides.
The services provided by the instrument are http (_http._tcp) and lxi (_lxi._tcp).
VISA Resource Name
Because of the limited support for VXI-11(Discovery Protocol only), the instrument must be
referred to by its raw socket information when used in software packages which communicate via
a VISA resource name. For example, an instrument at IP address 192.168.1.100 would normally
have a VISA resource name of "TCPIP0::192.168.1.100::inst0::INSTR" but for this instrument the
name must be modified to read "TCPIP0::192.168.1.100::9221::SOCKET" where 9221 is the
TCP port used by this instrument for control and monitoring, see below.
XML Identification Document URL
As required by the LXI standard, the instrument provides an XML identification document that
can be queried via a GET at “http://<hostname>:80/lxi/identification” that conforms to the LXI
XSD Schema (available at http://www.lxistandard.org/InstrumentIdentification/1.0) and the W3C
XML Schema Standards ( http://www.w3.org/XML/Schema ). This document describes the
instrument.
TCP Sockets
The instrument uses 2 sockets on TCP port 9221 for instrument control and monitoring. Text
commands are sent to this port as defined in ‘Remote Commands’ and any replies are returned
via the same port. Any string must be one or more complete commands. Commands may be
separated with either semicolons “;” or line feeds. No terminator is required since the TCP frame
contains complete commands though commands may be sent with a terminator if desired (it will
be ignored). Each command over TCP behaves as if it is terminated with a command terminator
(ASCII character 0AH, line feed).
