Slow Speed Adjustment - Dawn CONTROL-1500A Manual

CONTROL-1500A Single Axis Antenna Controller
from both Ku and C band satellites, use Ku band satellites for making the adjustments as
the antenna beamwidth will be narrower at Ku band.
5. Find a satellite that is at approximately the same longitude as the antenna. Motor the
antenna so that the antenna is at its highest elevation angle. This should be somewhere
near the center of travel about the polar axis. Vary the antenna's East-West Bearing and
Latitude angle to peak up the received signal strength.
6. Find a satellite to the east or west of the antenna longitude. Motor the antenna to peak up
signal strength. Push up or down on the lower edge of the reflector. Note whether a push
up or down increases signal strength. Use table 3.4 to adjust the East-West Bearing angle.
7. Go back to the satellite found in step 5. Push the reflector up or down. If the pushing the
reflector up increases signal strength decrease the mount's Latitude angle. If pushing the
reflector down increases signal strength increase the mount's Latitude angle.
8. Repeat steps 6 and 7 a number of times. For step 5, try to use satellites to both the east
and the west of the antenna location. As the adjustments become smaller, choose
satellites located farther to the east or west relative to the antenna longitude.
9. After steps 6 and 8 have been repeated a number of times, the mount should track the
geostationary arc if the declination angle is correct. If the antenna is tracking 'above' the
arc when looking at satellites to BOTH the east AND west the declination angle may have
to be increased. If the antenna is tracking 'below' the arc when looking at satellites to the
east and west the declination angle may have to be reduced. If the declination angle is
changed the latitude angle will have to be adjusted again as outlined in step 7
3.5

Slow Speed Adjustment

The Adapti-Drive slow speed control system allows the user to specify a desired rate of slow
speed movement. When the antenna is moving at slow speed the controller will vary the
voltage applied to the motor to maintain the desired slow speed. Other dual speed drive
systems in use reduce the voltage to the drive to a constant value whenever slow speed
movement occurs. This results in poor speed regulation as the load on the motor varies.
For the CONTROL-1500 the user sets the slow speed by entering a slow speed code via the
slow Speed CONFIG mode prompt. This section outlines the procedure for selecting the
appropriate slow speed code. When the system memory is reset the slow speed code is
initialized to 254 (maximum). If the speed code for a given axis is set to 254, the slow speed
system is disabled, and full voltage is applied to the axis whenever slow speed is selected.
When slow speed movement occurs, the CONTROL-2000C determines the speed at which the
actuator is moving by measuring the rate at which position feedback pulses are received. The
controller adjusts the voltage to the drive by using a Pulse Width Modulation (PWM) scheme,
which essentially turns the 36 volt drive voltage off and on very rapidly. Whenever the antenna
is manually jogged at slow speed (in MANUAL or SETUP mode) an indication of the voltage
delivered to the drive is displayed to the right of the 'SLOW' banner. This quantity, referred to
as a 'voltage code', varies from 1 to 24. The drive voltage associated with a voltage code of 1
is the minimum voltage which can be delivered to the actuators. A voltage code of 24 is
associated with the maximum voltage which can be delivered to the drive. If the speed code is
DAWNco • 3340 S. Lapeer Rd • Orion, MI 48359-1320 • Ph (248) 391-9200 • Fax (248) 391-9207 • sales@DAWNco.com
Chapter 3 Installation/Setup 25