MSA Senscient ELDS 1000 series, Operating Manual

Page: 43 / 184

Installation Design & Engineering
Senscient ELDS™
Rev 15 43
GB
Arrangement for Multiple Cross-Duct ELDS™ Systems
For applications where three (3) or more Cross-Duct units are required it is necessary to ensure
that the maximum possible separation occurs between Rx units. The recommended arrangement
for 3 systems in a duct is illustrated below.
Here 3 ELDS™ cross-duct systems are mounted at a common location in a duct of width w. The
‘middle’ system is mounted with the beam in the opposite direction to the top and bottom systems
so it cannot interfere with either of the other two units and they cannot interfere with it. There is a
possibility of interference between the two units that are mounted in the common direction
however. The angular separation between these two units (top and bottom) is approximately given
by the following relation:
Π
×
=
w
d 180
θ
where is the angle (in degrees) between the two transmitters pointing in the same direction and
(Pi) is 3.142.
Senscient recommends that the value of be at least 10 degrees.
As an example, for a duct of width (w) of 2.5 metre the angular recommendation above would
require that the separation of the top and bottom Rx units be at least 0.44m.
In another example, for a duct width of 5m the angular recommendation would require a value of d
of at least 0.87m.
Tx
Rx
Tx
Tx
Rx
Rx
d
w