Operating instructions

RC2000 Antenna Controller Interface Box
5
Note that the scheme shown in Figure 1 does not support slow speed movement. RC2000 antenna
controllers normally vary motor speed by rapidly switching the 36 volt antenna drive signals off and on -
which gives an average voltage of less than 36 volts. If this pulse width modulated signal is applied to the
circuit of Figure 1, the relays would chatter and produce erratic operation. When using the interface boxes
described here with the RC2000, slow speed operation should be disabled on the controller by setting the
azimuth and elevation slow speed codes to 254. The single speed of the interface box is adjusted by
varying a pot on the drive module(s).
Slow speed movement via the interface box is supported however. The RC2000 software can use the
controller’s polarotor output to control a relay which provides a pair of contact closures (NO, COM, and
NC) which specify fast or slow speed antenna movement. Note that polarotor control is not supported with
the RC2000 controller in this mode but polarization control via the optional RC2KPOL daughterboard is
still available.
2.2 Position Sensor Interface
The RC2000 series of antenna controllers require the use of single phase pulse type sensors to determine
the position of the antenna. A pulse type sensor produces a rectangular shaped waveform as the antenna
moves about the axis associated with the sensor. The RC2000 antenna controllers are not compatible with
quadrature pulse sensors. 5.7 volts DC is available on the back of the RC2000 (at connector J1-11) to
provide power for the pulse sensors.
The RC2000 controllers count the number of rising and falling edges of the waveform. The position count
is decremented for east (or down) movement and incremented for west (or up) movement. Referring to
Figure 2, the waveform's high level should be 4.5 to 5.7 volts, and the low level should be 0.0 to 0.5 volts.
The waveform's minimum high or low pulse duration should be at least 10 milliseconds. This means that
pulses less than 10 milliseconds long may not be detected by the antenna controller. The maximum
number of counts from the antenna's east limit to its west limit should be less than 65000. Remember, each
rising edge and each falling edge of the sensor's output waveform is a separate count.
Volts
time
0.0V
0.5V
4.5V
5.7V
High level Waveform
duration greater than
10 m Sec
Low level Wavefor m
duration greater than
10 m Sec
The m axim um num ber of edges (rising or falling)
must be less than 65000.
Figur e 2.