User manual
50
Serial Bus Analysis
14 Remote Control
The R&S®HMO1002 is equipped with a built-in interface
card, which have an Ethernet and USB connection on
board as a standard.
In addition to a LAN interface, the R&S®HMO1002 includes
a USB device port. For this interface, the user can select if
the instrument is accessed via virtual COM port (VCP) or
via USB TMC class.
14.1 USB VCP
The traditional version of the VCP allows the user to com-
municate with the measuring instrument using any termi-
nal program via SCPI commands once the corresponding
Windows drivers have been installed. The actual USB-VCP
driver can be downloaded from the Rohde & Schwarz
homepage www.rohde-schwarz.de for free. If a connec-
tion between PC and the instrument has been established
and no HMC USB-VCP driver is installed, the operating
system answers with “Found New Hardware”. In addition,
the “Found New Hardware Wizard” is displayed. Only in
this case the USB-VCP driver must be installed. Further
information about the USB VCP driver installation you can
ndintheinstallationguideinternalofthedriverle.
In addition, you may use the free HAMEG software
„HMExplorer“. This Windows application offers the
R&S®HMO1002 a terminal function, the option to create
screenshots and to sort the measured data storage.
To make any communication possible, the chosen interface and
it’s correcponding settings must be the same in the PC as in the
oscilloscope..
All currently available USB VCP drivers have been fully tested
and released for Windows XP™, VISTA™, Windows 7™ and Win-
dows 8™ (32 + 64 Bit).
The following requirement for USB-VCP driver installation are
necessary:
1 R&S®HMO1002 with an activated USB-VCP interface.
2 A PC with operating system Windows XP™, VISTA™, Win-
dows 7™ oder Windows 8™ (32 or 64Bit).
3 Administrator rights are necessary for the installation of the
driver. If an error message regarding spelling errors appears,
the rights to install the driver are not given. In this case,
please contact your IT department to obtain the necessary
rights.
14.2 USB TMC
A modern alternative to the virtual COM port (VCP) is
the control via USB TMC class. TMC stands for „Test &
Measurement Class“ which indicates that the connec-
ted measurement instrument can be recognized without
special Windows drivers if VISA drivers are installed and
that it can be used directly in corresponding environments.
The GPIB interface serves as model to the structure of the
TMCdesign.AmajorbenetoftheUSB TMC class is that
bysamplingspecicregisterstheusercandetermineif
commands have been terminated and if they have been
processed correctly. However, the communication via VCP
requires analysis and polling mechanisms within the cont-
rollingsoftwarewhichmaysignicantlystraintheinterface
of the measurement instruments. The TMC status registers
solve this problem with the USB TMC in the same manner
as is the case with the GPIB interface for the hardware,
namely via corresponding control lines.
14.2.1 USB TMC Conguration
The R&S®HMO1002 require a generic USB instrument
driver to be operated in USB-TMC mode. The USB Test &
Measurement class (USB-TMC) is a protocol that enables
GPIB-like communication via USB interfaces and a sepa-
rateinstrumentclassoftheUSBspecication.TheUSB-
TMC protocol supports service requests, trigger and other
GPIB-speciccommands.ThedriverisincludedintheNI-
VISA package (Virtual Instrument Software Architecture)
and can be downloaded at http://www.ni.com/downloads/
ni-drivers/.
YouneedtorstinstalltheNI-VISAdriversonyourWin-
dows system. Please download the most recent version
of the NI-VISA driver package. Extract the previously
downloaded driver package and follow the installation
instructions.
BelowpleasendanexampleforNI-VISA5.4.1:
The HMExplorer software does not support the communication
via USB TMC.
Fig. 14.1: NI-VISA 5.4.1