RESEARCH CONCEPTS RC2000A DUAL AXIS Instructions Manual page 48

48 RC2000A Dual Axis Antenna Controller
ELEV MAX POSITION ERROR: 1
0-10 COUNTS
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
2-5
ELEV AUTO RETRY ATTEMPTS:3
2-5
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.
Configuring the Runaway Sensing System
The user can modify the operation of the runaway alarm sensing system via the values assigned to the
Azim Fast Deadband and Elev Fast Deadband CONFIG mode items. Each axis can be configured
separately.
If the value assigned to the Azim Fast Deadband CONFIG mode item ends in '40' the controller will only
accumulate azimuth position counts when the antenna is moving about the azimuth axis or is in a coast
interval immediately proceeding an azimuth move. This effectively disables the runaway alarm for the
azimuth axis. The operation of the elevation runaway sensing system is configured via the Elev Fast
Deadband CONFIG mode item in a manner similar to that of the azimuth axis. Examples of 'Fast
Deadband values that disable runaway sensing are 2040 and 940.
If the value assigned to the Azim Fast Deadband CONFIG mode item ends in '41' through '49' the
azimuth runaway count threshold will be assigned a value of 1 through 9, respectively. The azimuth
runaway count threshold is defined as the number of runaway counts that must be exceeded before an
azimuth runaway alarm is triggered. For example, if the Azim Fast Deadband CONFIG mode item has
a value of 1845 six runaway position counts must be accumulated before an azimuth runaway alarm is
triggered. The elevation axis is configured in a similar manner using the Elev Fast Deadband CONFIG
mode item.
Research Concepts, Inc. • 5420 Martindale Road • Shawnee, Kansas • 66218-9680 • USA
Chapter 4
CONFIG
ENT,BKSP,SCRLL ^v
CONFIG
ENT,BKSP,SCRLL ^v
CONFIG
ENT,BKSP,SCRLL ^v
Modes
www.researchconcepts.com