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The Baud Rate for this instrument is fixed at 9600; the other parameters are 8 data bits, no parity
and one stop bit. Flow control uses the XON/XOFF protocol, but because of the low volume of data
associated with this instrument it is very unlikely that flow control will actually be invoked.
14.3
USB Interface and Device Driver Installation
The instrument firmware can be updated in the field through the USB port. This does
not
need the
driver described here. It requires a PC software utility provided by the manufacturer, and uses a HID
driver that will already be installed on the PC. If that is the only USB functionality required, download
the package containing the firmware update together with the PC utility from the manufacturer, and
follow the instructions included.
Using the USB interface for remote control requires a Communications Device Class driver on the
PC to provide a virtual COM port instance. In Windows a suitable driver is provided by Microsoft, but
it is not installed by default. The data (.INF) file to control the installation is provided on the Product
Documentation CD delivered with the unit; however the same driver is also used by many other
instruments from this manufacturer and may already be known to the PC.
To install the driver for the first time, first switch the unit on, and then connect the USB port to the
PC. The Windows plug and play functions should automatically recognise the attachment of new
hardware to the USB interface and (possibly after searching the internet for some time) prompt for
the location of a suitable driver. Follow the Windows prompts and point to the CD, then the sub-
directory for this product, and then to the USB Driver sub-directory below that. The file is named
USB_ARM_VCP_xxx
.
INF, where xxx is a version number. (A readme.pdf file will also be found in
that directory if further assistance is needed.)
In some cases Windows will not complete this procedure (especially recent versions which search
the internet first, looking for the unique Vendor ID and Product ID), in which case the instrument will
show in Device Manager as “not working properly”. If this happens, select this device, right click and
choose “update driver software...” and then “browse this computer for driver software...” and then
locate the .INF file on the CD as described above.
Once Windows has installed the device driver it will assign a COM port number to this particular
unit. This number will depend on previous COM port assignments on this PC, and it may be
necessary to use Device Manager to discover it. Each instrument has a unique USB identifier which
is remembered by the system, so it will receive the same COM port number whenever it is attached
to the same PC (regardless of the physical interface socket used), even though the COM port will
disappear while the instrument is disconnected or switched off. Other instruments will receive
different COM port numbers.
Note that a different PC will not necessarily assign the same COM port number to a particular
instrument (it depends on the history of installations), however Device Manager can be used to
change the assignments given.
This virtual COM port can be driven by Windows applications (including a terminal emulator) in
exactly the same way as any standard COM port, except that the Baud rate and other settings are
unnecessary and are ignored. Some old applications might not function with COM port numbers 3 or
4, or above 9. In this case, use Device Manager to change the allocation given. Once it is installed,
the driver will be maintained by Windows Update in the usual way.
14.4
LAN Interface
The LAN interface is designed to comply with the LXI standard version 1.4 LXI Core 2011 and
contains the interfaces and protocols described below. For more information on LXI standards refer
to
www.lxistandard.org
.
When powered up and attached to a network, the unit will by default attempt to obtain IP address
and netmask settings via DHCP, or, if DHCP times out (after 30 seconds), via Auto-IP. In the very
unlikely event that an Auto-IP address cannot be found a static IP address is assigned; the default is
192.168.0.100, but this can be changed on the web page. Connecting via a router is recommended
as this is significantly quicker to assign an IP address; connecting directly to a PC will only begin to
assign an Auto-IP address after the 30 second DHCP timeout.
