Research Concepts RC2000A - Manual (Page 26)

26 RC2000A Dual Axis Antenna Controller Chapter 3 Installation
When polarization angle display is disabled, the polarization position has a maximum possible range of
movement of 0 to 1023. Note that some potentiometers will not move over the entire range. When
moving the polarization motor (in the steps that follow) be very careful not to exceed the potentiometer's
mechanical limits - potentiometers are very susceptible to damage when moved past their mechanical
limits.
4. In this step the polarity of the polarization motor and sensor wiring is checked. This step of the
procedure is performed in the POL LIMITS mode.
The motor polarity is somewhat arbitrary. The polarization jog keys are labeled CW and CCW. The
user is free to define the direction sense as he or she wishes. The important thing to remember is that
when the polarization motor is jogged CCW (by hitting the CCW key) the position count MUST
INCREASE. If this is not the case, the 5 VOLT REF and GROUND wires must be swapped. Note that
shield must always be connected to the GROUND terminal.
The motor may be jogged in POL LIMITS mode. Note that in this mode there are no limits on
polarization movement. The user must be careful to not move the polarization motor past a limit.
Damage to the antenna feed, polarization motor, or potentiometer may occur if the limits are exceeded.
If the user attempts to move the polarization motor and no movement is detected on the position sense
lines, or movement is in the wrong direction, the ANTENNA POL alarm will activate. Remember, when
the polarization is jogged counter-clockwise (with the CCW key), the count MUST increase. If a
polarization alarm is active, an error message will flash on the bottom row of the display and the
polarization drive will be disabled. The alarm can be de-activated via RESET mode.
5. Once the polarity of the motor drive and sense lines have been verified, the polarization limits may
be set. This is done from the POL LIMITS mode. To set the limits, the user positions the
polarization motor at each limit (through the use of the CW and CCW keys) and hits the 5 key. Note
that in POL LIMITS mode there are no restrictions on polarization motor movement. It is
recommended that an assistant be stationed at the antenna to ensure that the polarization motor's
(or sensor's) mechanical limits are not exceeded. Damage to the antenna feed, polarization motor,
or sensor may occur if the limits are exceeded.
6. This section describes how to enable and calibrate the angle display of polarization position. Angle
display is enabled by setting the CONFIG mode 'Pol Angle Display' item to 1.
To calibrate the angle display, the user must initialize the CONFIG mode 'POL DISPLAY 0 DEG CNT'
and 'POL DISPLAY 90 DEG CNT' items. The position entered at the 'POL DISPLAY 0 DEG CNT' will
display 0.0 degrees and the position entered at the 'POL DISPLAY 90 DEG CNT' prompt will display as
90.0 degrees. All intermediate positions are scaled appropriately. The maximum possible range of
displayed angles is from -99.9 degrees to 999.9 degrees.
It is not necessary to enable and calibrate the angle display at this time. These CONFIG mode items
may be initialized after some satellites have been entered into the controller's non-volatile memory.
3.4 Setting Azimuth and Elevation Limits
The next step in the installation procedure is to ensure that the polarity of the motor drive wiring is
correct, the position sensors and polarotor function properly, and then to set the azimuth and elevation
limits. All of the operations outlined in this section can be carried out with the controller in LIMITS
mode.
IN LIMITS MODE THE USER HAS UNRESTRICTED MOVEMENT OF THE ANTENNA, THERE ARE
NO SOFTWARE AZIMUTH OR ELEVATION LIMITS, AND ANTENNA JAMMED SENSING DOES
NOT TAKE PLACE. WHEN MOVING THE ANTENNA IN LIMITS MODE AN ASSISTANT SHOULD
BE STATIONED AT THE ANTENNA TO INSURE THAT THE ANTENNA DOES NOT MOVE PAST A
PHYSICAL LIMIT. NOTE ALSO THAT THE CW AND CCW POLARIZATION ADJUSTMENT KEYS
ARE ACTIVE.
3.4.1 Motor Drive Polarity
The polarity of the azimuth motor drive is checked by depressing the AZ CCW (AZ CW) ARROW key
and verifying that the antenna moves in the proper direction. The sense of azimuth movement is
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