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RC2000 Antenna Controller Interface Box
Please refer to the discussion of these CONFIG mode items in the RC2000 manual. Failure to properly
configure these CONFIG mode items can result in inaccurate antenna positioning and/or excessive wear
on the motors and actuators.
Two of the CONFIG mode items have special features which are often useful in interface box
applications. The last two digits of the Az/El Fast Deadband parameter can be configured so as to disable
antenna runaway errors. The last two digits of the Az/El Slow Deadband parameter can be configured so
as to address the problem of gaps in the program track table which contains a map of an inclined orbit
satellite's apparent motion. For a discussion of these features of these two CONFIG mode items please
refer to the RC2000C manual, Section 7.3 - Operational Troubleshooting Tips.
Many interface box applications are used for inclined orbit satellite uplinks. For transmit applications it is
generally advisable to disable the controller's Search Enable CONFIG mode item. When the search is
enabled, if the antenna is steptracking and the controller's AGC input indicates that the satellite signal has
been lost the controller will initiate a search. During a search the controller sweeps the antenna over a
parallelogram shaped region where it has calculated that the satellite is likely to be found. This is generally
not desirable for transmit applications.
5.4 Interface Box Adjustments
Several user adjustments are available on the KBPB motor drive module and the 2K90INT-2 board located in
the interface box. The most common adjustment made is to vary the speed of the motors. On interface boxes
made for single-speed antenna movement, the speed is adjusted using R14 on the KBPB motor drive. This pot
is labeled 'AUX' or R14. Please refer to the KBPB manual for the location of this pot. The AC power to the
interface box should be disconnected whenever the interface box is opened - lethal voltages are present
inside the box.
4.4.1 Speed Control
For interface boxes configured for dual speed azimuth and elevation movement, the slow speed adjustment pots
are located on the 2K90INT-2 circuit board. For the RC2K90INT-1 interface box adjust the KBPB1_SLO pot
to vary the slow speed for both the azimuth and elevation axis. Adjust the KBPB1_FST pot to set the fast speed
for both axis. For the RC2K90INT-2 interface box the KBPB1_SLO and KBPB1_FST pots are used to adjust
the speed of the azimuth axis. The KBPB2_SLO and KBPB2_FST pots are used to adjust the speed of the
elevation axis. The maximum and minimum fast and slow speeds for each KBPB are determined by the MAX
and MIN trimpots located on each KBPB. Normally the user should not need to adjust these pots - they are set
for maximum speed-range when the interface box is assembled.
4.4.2 IR Compensation and Current Limiting
Other trimpot adjustments present on the KBPB are the IR compensation and current limiting. IR
compensation is used to increase the voltage to the motor when the motor is loaded so as to maintain a
constant speed. Current limiting limits the current applied to the motor. This protects the motor against
overloads both while running and at startup. Both of these parameters are controlled via trimpots and with
the Plug-In Horsepower Resistor. If the controller was ordered with the proper resistor no adjustment of
these trimpots should be necessary. If adjustments are necessary please refer to the KBPB operating
instructions included with this manual.
4.4.3 Fusing
The KBPB motor drive module has provisions for a built-in AC line fuse and an Armature Fuse. An AC
line fuse of 12 amps is appropriate for 90 VDC motors of up to 3/4 HP and 180 VDC motors of up to 1 1/2
horsepower. For larger motors use a 25 amp AC line fuse. To calculate the size of the armature fuse,
multiply the full load DC current rating of the motor by 1.7. Both fuses are normal blow, ceramic type
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