Research Concepts RC2000A - Manual (Page 44)

44 RC2000A Dual Axis Antenna Controller Chapter 4 Modes
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: 1 CONFIG
0-10 COUNTS ENT,BKSP,SCRLL ^v
ELEV MAX POSITION ERROR: 1 CONFIG
0-10 COUNTS ENT,BKSP,SCRLL ^v
The 'Auto Retry Attempts CONFIG mode items set the maximum number of attempts which will be
made to hit a target position (within 'Max Position Error counts - described above) during an automatic
move initiated from AUTO mode.
AZIM AUTO RETRY ATTEMPTS:3 CONFIG
2-5 ENT,BKSP,SCRLL ^v
ELEV AUTO RETRY ATTEMPTS:3 CONFIG
2-5 ENT,BKSP,SCRLL ^v
The 'Fast Deadband and 'Slow Deadband CONFIG mode items are used for the anti-reversal system.
To understand the purpose of these parameters, it is necessary to consider how position counts are
accumulated. The feedback from the azimuth and elevation position sensors is a pulse-train. When a
pulse is received, the controller checks to see which way the antenna was last commanded to move. If
the antenna is moving, or last moved, counter-clockwise (down), the azimuth (elevation) position count
is decremented. If the antenna is moving, or last moved, clockwise (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 4 different 'Deadband values specified - there are unique fast and slow speed values for each
speed and each axis. 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. All 'Deadband values are given in milliseconds.
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