Research Concepts RC2500 - Manual (Page 69)

62 RC2500 Antenna Controller Chapter 7 Troubleshooting/Alarm Codes
Research Concepts, Inc. • 5420 Martindale Road • Shawnee, Kansas • 66218-9680 • USA www.researchconcepts.com
situation, try to eliminate the slop in the mount. If this is not possible, always approach each satellite from
the same direction in which it was originally programmed (typically east to west).
ANT AZIM, ANT ELEV or ANT POL ERRORS OCCUR
To determine the cause of this error, go to RESET mode. One of the following error messages will be
displayed: JAMMED, RUNAWAY, or DRIVE. Here are the likely causes of each of these errors:
JAMMED - This error indicates that the drive was commanded to move, but movement was not sensed.
This can be caused by an mechanical jam at the antenna, or the antenna may be moving but position
feedback changes are not getting back to the controller. Determine which condition exists.
If the antenna is not moving there may either be a faulty motor, a wiring problem, or a mechanical limit
switch has been encountered and is not registering at the controller. If the antenna is moving but position
changes are not reaching the controller, check the resolver wiring and the physical mounting of the
resolver on the antenna mount.
RUNAWAY - This error occurs when are large, unexpected position change is encountered when the
antenna has not been commanded to move. If the Antenna has not actually moved, check the resolver
wiring for intermittent connections.
DRIVE - This error indicates that the motor drive modules located in the A.I.U. have encountered a fault
condition. This fault condition may be due to a temporary over-current or an actual drive failure. The
failure may be reset in RESET mode. If the problem persists, check the documentation received with the
A.I.U. for possible causes of the drive fault. See Section 5.6.
ENTRY SELECTED HOLDS INVALID DATA
When a satellite is selected via auto mode, the controller displays the message “ENTRY SELECTED
HOLDS INVALID DATA”. Before the controller executes an automatic move it checks to see if the
azimuth, elevation, and polarization (if any) data items are valid. If they are not, the error message is
displayed. This error can also occur if the state of the POL CONTROL EQUIPMENT CODE CONFIG
mode item was changed after the satellite was programmed into non-volatile memory.
GAPS IN THE TRACK TABLE
If the program track table has gaps even though the transponder has not powered down, there may no be
a problem and just a slight change in a CONFIG mode item may be in order. In TRACK sub-mode, the
controller periodically peaks the antenna. Two events can trigger a peaking operation. The antenna will
peakup at the sidereal times corresponding to entries in the track table, and store the peak azimuth and
elevation antenna positions. A peaking operation will also occur whenever the controller calculates that
the antenna pointing error could exceed the error specified by the Max Track Error CONFIG mode item
because of the satellite's apparent motion. The controller calculates this time interval by knowing the
satellite's inclination, and calculating the antenna beamwidth based on the antenna size and frequency
band.
Since the track table has 48 entries and a sidereal day is 23 hours, 56 minutes and 4 seconds long, a
track table-inspired peakup will occur roughly every 30 minutes. A problem can arise if a Max Track Error
inspired peakup is in progress when the track table peakup should occur - the controller will not perform
the track table peakup, and no azimuth and elevation position data will be stored in the track table. This
causes gaps in the track table data (which may be examined via the TRACK MENU - VIEW function). To
prevent this from occurring, the controller will not initiate a Max Track Error peakup within 120 seconds
prior to a sidereal time which corresponds to a track table entry. The 120 seconds is referred to as the
Peakup Holdoff Interval.
The user can change the Peakup Holdoff Interval by manipulating the value of the Az/El Slow Deadband
CONFIG mode item. If the Az/El Slow Deadband CONFIG mode item is a multiple of 50, the default
value of 120 seconds is used as the Peakup Holdoff Interval. The user can select any Peakup Holdoff
Interval (up to 500 seconds) by selecting a Peakup Holdoff Interval which is not a multiple of 50.
The relationship between these two items is illustrated by way of an example:
Az/El Slow Deadband = 818 milliseconds