Geometrics, Inc. G-824A Magnetometer Manual
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7.2 Installing Driver for USB to Serial Converter
Since today's consumer laptop and desktop computers no longer have RS-232 serial ports,
it's necessary to use a USB to RS-232 SERIAL port adapter to configure and collect data
from the G-824A. If your host computer does have an RS-232 Serial port, you can connect
that host computer to the G-824A directly, in which case you may skip this section and
advance to section 7.1.2. Geometrics has tested several USB to Serial adapters for its
customers and have found two reliable models for field use. One of these is the Gearmo
USA-4P-232, which is a 4-Port Serial Adapter to connect up to four serial devices to one
USB port (Geometrics Part # 20-000-072), and the other is the Gearmo USA-FTDI-A36
single port adapter (Geometrics Part # 20-000-071) which is supplied with the G-824 and
described here.
To install either of these USB to SERIAL adapter on your Windows computer, make sure
that the USB-Serial converter is not connected to the host computer and insert the USB-
Serial converter's driver installation CD into the computer's drive. You can also download
the FTDI USB-Serial driver from
http://www.ftdichip.com/FTDrivers.htm
. Follow the
instructions as prompted to install the Windows driver. These two USB-Serial adapters use
the same Windows driver, so it only necessary to install the driver one time on each
computer to be used. For LINUX operating systems, simply insert the USB-SERIAL
converter into your computer's USB Port and go to section 7.2.1.
7.2.1 Configuring the FTDI Driver
By default the adapter’s driver is configured to provide maximum efficiency in terms of
data transmission; this might produce an undesirable “blocking” effect on the data,
causing multiple data strings to arrive at the same time due to blocking in the Windows
kernel. This also has adverse effect if adapter is used with PPS based time server. To
reduce above shortcomings the following configuration settings can be adjusted:
1.
Plug the USB-Serial Converter into your computer to be used to interface with the
G-824A, and wait 15 to 30 seconds for the USB-Serial converter to be recognized
by the Windows operating system
2.
Locate the “Device Manager” in your version of Windows and locate the “Ports
(COM & LPT)” icon in the list (as shown below). This can be done by clicking
the “START” button and typing in “Device Manager in the blank field
immediately above it, and then clicking on the “Device Manager” option shown
in that window.
