Geo Elevation Position - RESEARCH CONCEPTS RC2000C Manual

RC2000C Polar Tracking Antenna Controller
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.
To determine the slow speed code which is appropriate for the azimuth axis, use the following procedure.
For 36 volt DC linear actuators, slow speed codes of 140 to 180 are common.
1. In MANUAL mode jog the antenna in azimuth at FAST speed for exactly 10 seconds and record the
number of counts which occur. Make sure that the antenna does not reach a limit during the move.
2. Use the following table to determine an initial setting for the speed code.
counts
60
70
80
95
120
145
170
200
250
3. Go to CONFIG mode and use the SCROLL keys to bring up the Azim Slow Speed item. Key in the
new speed code followed by the ENTER key.
4. Go to MANUAL mode, toggle the speed to SLOW, and jog the antenna in azimuth. Continue jogging
the antenna until the voltage code displayed to the right of the SLOW banner settles to a steady state
range of values. This may take 5 to 10 seconds. If a limit is reached, jog the antenna in the opposite
direction. After the voltage code settles to a steady state range of values, check the rate of
movement to make sure that it is slow enough to be useful but not so slow that the motor stalls or
moves in a jerky fashion. If the movement is not satisfactory increase or decrease the speed code by
3 to 5 counts. Increasing the speed code results in a faster rate of slow speed movement. Repeat
steps 3 and 4 until satisfactory slow speed movement is attained.
A similar procedure is used to adjust the elevation slow speed. The elevation slow speed code is entered
at the CONFIG mode Elev Slow Speed prompt, and the user jogs the antenna about the elevation axis to
check the rate of slow speed movement.
3.6

Geo Elevation Position

The Geo Elevation Position is the elevation actuator position where the antenna can be positioned on all
of the geostationary satellites by just changing the antenna's azimuth position. This assumes that the
antenna mount has been configured as described in section 3.4.2. The tracking algorithms assume that
the center of the figure eight pattern which describes the satellite's apparent motion is at the elevation
angle which corresponds to the Geo Elevation Position. The Geo Elevation Position is entered into non-
volatile memory via CONFIG mode. The Geo Elevation Position CONFIG mode prompt is described in
section 5.10.5.
When system memory is cleared, the Geo Elevation Position is reset to zero. Whenever the Geo
Elevation Position is zero, the elevation position which is displayed will be the actual elevation position
count, the down limit is 30, and the up limit will be some value greater than 30. Once the Geo Elevation
Position has been set, all elevation position values are displayed relative to the Geo Elevation Position.
When the antenna is located at the Geo Elevation Position (assuming it has been set), the displayed
elevation position will be 0.
A simple example will illustrate the interaction between the Geo Elevation Position and the elevation
display. The user enter LIMITS mode and sets the east limit. After the east limit is set, the displayed
Research Concepts, Inc. • 5420 Martindale Road • Shawnee, Kansas 66218-9680 • USA
speed counts
code
80 300
90
100
110
120
130
140
150
160
Chapter 3
speed
code
165
350 170
415 175
525 180
715 185
1100 190
1325 195
1450 200
Installation/Setup 19
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