Setup guide

39
G2 Wireless Experimentation
The following section is a summary of in-house testing, which describes some specific, very
basic tests that were done to demonstrate the feasibility of wireless Ethernet as a means of
communication between the Gravimetric Gateway software and the Maguire Weigh Scale
Blenders. Each test used in-expensive, off the shelf wireless components and tested under
different wireless configurations in settings similar to an actual production environment.
The goal of each test was to examine the factors that limited wireless communications and
find specific configurations that met the average distance requirements of a typical G2
installation while keeping costs to a minimal.
The results of these tests demonstrated that wireless Ethernet communications are possible
when the transmission speed was reduced to the minimal 1Mbps and obstructions between
wireless devices were kept to a minimal. Distances were not as much of a factor as
obstructions and where line of sight was possible distances can reach considerably more than
when obstructions are present. When obstructions were a factor, such as block walls, a
repeater was tested to re-transmit the signal to the “dead spot” in the wireless topography. In
these tests we were able to transmit a non-interrupted wireless signal through several layers of
drywall, as well as through cinder block walls when doorways were present while using the
lowest transmission rate.
Two basic setups were used at the controller in these tests. One setup used a combination of
an Ethernet to Serial Converter and a wireless bridge. Together they convert a wireless
transmission to wired Ethernet, then from Ethernet to Serial (diagram below, left). The other
setup used a Wireless Serial Server that combined IEEE 802.11b wireless technology with an
Ethernet to Serial converter (diagram below, right). Additional devices such as a WAP11 in
Repeater Mode and another WET11 on the G2 Server computer were used with these two
basic setups.
In some tests an optional 5.5 dBs antenna with a magnetic base and 1.8 meter of extension cable
was tested. This antenna seemed to significantly decreased signal strength. Loss of the wireless link
to the Access Point was frequent in most locations with even the lowest transmission rate. It was
found that the Magnetic base antenna decreased overall distance significantly.
Test Blender 1 Test Blender 2 G2 Server Access Point (WAP11)