ETS-Lindgren 2090 Controller - Manual (Page 61)

Model 2090 Multi-Device Controller
For towers equipped with air polarization, pressing the
POLARIZATION key, while the current position is shown
in the display, will toggle the state of the air solenoid valve
in the motor base. The HOR or VERT indicator will light
to indicate the state of the solenoid. If the Polarization
Offset (parameter P4 on a standard tower) is non-zero, the
value will be added or subtracted from the current position
depending on the target polarization. In moving from
horizontal to vertical polarization, the value will be
subtracted, since the antenna will rotate from being the
offset distance above the centerline of the boom to being
that distance to the side. In moving from vertical to
horizontal, the value will be added to the current position.
The actual motion of the polarization mechanism is
determined by various factors, including available air
pressure and flow control settings on the air polarization
piston cylinder. There is no feedback to indicate that the
cross boom has completed the polarization cycle. The user
should allow a certain amount of time for the polarization
cycle to complete before continuing testing, or use visual
feedback (i.e. from a camera system) to verify that the
polarization operation has completed.
If the current position at the target polarization is outside
the limits of the target polarization, the Model 2090 will
generate a Polarization Limits Violation ( E006 ) error and
not allow the tower to polarize. As described in the
configuration information, the Model 2090 provides two
sets of limits, one for each polarization, designed to protect
antenna elements from damage. (The Model 2090 provides
©ETS-Lindgren, April 2006 61
Revision G– P#399199