CONTROL-
1500A Single Axis Antenna Controller Chapter 3 Installation/Setup
17
3.3 Polarization Control
The
CONTROL-
1500 supports two types of polarization control. The standard polarization
control
device is a Chapparal type Polarotor device. There is an optional polarization control
daughterboard (designated RC2KPOL) that interfaces to a rotating feed powered by a DC
motor that employs a potentiometer for polarization position sense. The RC2KPOL is often
interfaced to rotating feeds made by Seavey Engineering Associates. The
CONTROL-
1500
always
assumes that a polarization control device is connected to the system – even if in fact
no
polarization control device is present at.
3.3.1 Configuring the
CONTROL-
1500 for Use in an Installation that Does Not Employ a
polarization
Control Device
When programming satellite’s into the controller’s non-volatile memory via SETUP mode the
user will be prompted to specify the horizontal and vertical positions associated with the
satellite. If no polarization control device is present in a given installation the controller must
be configured so that it thinks that a Polarotor device is present in the system. This is
accomplished by setting the
24 VDC Rot Feed
CONFIG mode item to 0 (No).
This works because the controller controls the Polarotor in an open loop manner. The
Polarotor provides no position feedback to the controller so the controller cannot tell if a
Polarotor is actually connected to the system or not. Once the controller is configured for
Polarotor operation, the installer should insure that the controller does not think that the
Polarotor is at a limit. To check for this, go to the MANUAL mode. If the controller thinks that
the Polarotor is at a limit “CW” or “CCW” will be displayed in the polarization position field. To
correct this condition depress the Pol CW or Pol CCW key to ‘position’ the polarotor away from
the limit.
3.3.2 Configuring the
CONTROL-
1500
A
for use with a Polarotor
The Polarotor is a 3 wire servo that controls the orientation of probe in the throat of the feed
assembly. To configure the
CONTROL-
1500 to control a Polarotor device, set the
24 VDC Rot
Feed
CONFIG mode item to 0-No.
The Polarotor was originally developed by Chaparral Communications. Most Polarotor
modules use a standard wire coloring convention (outlined in the following table). A shielded
cable with a bare drain wire should be used to interface the Polarotor to the controller. The
shield is used in a manner identical to that described for the antenna position sense interface
in section 3.2.2.
Figures 3.2 and 3.3 show the connection of the Polarotor to the controller. The following table
details the interface of a Polarotor to the
CONTROL-
1500
A
…
CONTROL-
2000 Connection Signal Description Polarotor Wire Color
(typical)
J1-11 labeled 5.7 VDC
DC Power for the Polarotor
module.
Red
J1-10 labeled PULSE
Pulse Output to the
White
DAWNco • 3340 S. Lapeer Rd • Orion, MI 48359-1320 • Ph (248) 391-9200 • Fax (248) 391-9207 • [email protected]
