Research Concepts RC2000C - Manual (Page 64)

56 RC2000C Az/El Tracking Antenna Controller Chapter 5 Modes Function Description
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is received, the controller checks to see which way the antenna was last commanded to move. If the
antenna is moving, or last moved, azimuth CCW (down), the azimuth (elevation) position count is
decremented. If the antenna is moving, or last moved, azimuth CW (up) the azimuth (elevation)
position count is incremented.
In MANUAL mode, the user can jog the antenna. If the UP arrow key is depressed, the antenna will
move up. If the user suddenly depresses the DOWN arrow key and the antenna drive signals were
instantaneously reversed, the antenna continues to move up for some small period of time, then the
antenna reverses direction and starts to move down. This can cause position count errors. When the
antenna drive signals are configured for down movement but the antenna is still moving up, pulses
which are received would cause the elevation position count to decrement when the count should really
be incremented because the antenna is really still moving up.
The anti-reversal system keeps the antenna from rapidly changing direction. If the antenna has been
moving in a given direction, the 'Deadband CONFIG mode items specify the amount of time that the
system will wait before asserting the antenna drive lines to move the antenna in the opposite direction.
There are 2 different 'Deadband values specified - there are unique fast and slow speed values. If the
antenna has been moving fast, the 'Fast Deadband parameters specify the wait interval; if the antenna
has been moving slow, the 'Slow Deadband parameters specify the wait interval. Both 'Deadband
values are given in milliseconds.
AZ/EL FAST DEADBAND:2000 CONFIG
175-5000 MSEC ENT,BKSP,SCRLL ^v
AZ/EL SLOW DEADBAND: 800 CONFIG
175-5000 MSEC ENT,BKSP,SCRLL ^v
The values assigned to the Az/El Fast Deadband and Az/El Slow Deadband variables can affect other
systems on the controller not related to the anti-reversal system. These features are explained in
Chapter 7 - Operational Troubleshooting Tips. For normal operation these features should be disabled.
To DISABLE these features, make sure that the value entered for Az/El Fast Deadband DOES NOT
end in '01' (i.e. when the value is divided by 100 the remainder is not 1), and that the value entered for
Az/El Slow Deadband DOES end in either '00' or '50' (i.e. the value entered is a multiple of 50).
During an automatic move in AUTO or TRACK modes, the 'Coast Threshold CONFIG mode items set
the number of counts before the target position is reached where the drive will be deactivated. The idea
is to deactivate the drive and let the antenna coast into position. If prior to the initiation of the move
operation, the total number of counts that the actuator has to move to reach the target position is less
than the 'Coast Threshold, the drive will be deactivated when its position is within 'Max Position Error
counts of the target position.
AZIM COAST THRESHOLD: 4 CONFIG
1-40 COUNTS ENT,BKSP,SCRLL ^v
ELEV COAST THRESHOLD: 4 CONFIG
1-40 COUNTS ENT,BKSP,SCRLL ^v
The 'Max Position Error CONFIG mode items set the maximum acceptable error between the final
resting position and a target position for an automatic move which occurs in AUTO mode.
AZIM MAX POSITION ERROR: 0 CONFIG
0-10 COUNTS ENT,BKSP,SCRLL ^v