RC3000 Antenna Controller | Chapter 4 | Troubleshooting |
4.0 TROUBLESHOOTING
This section provides tips for debugging typical problems. There are many interfaces between the RC3000 and position sensors, limit switches, mechanical components of the mount, other satellite equipment, etc. Some problems are due to interactions that are not readily apparent. Review all of the troubleshooting sections to see if a situation similar to yours is described.
4.1 Limit Switches
The various limit switches serve as safety interlocks to prevent mount damage. The RC3000 checks for limit conditions via both software and a Programmable Logic Device on the analog board. The following table summarizes the interlock logic employed:
LIMIT
Azimuth STOW
Azimuth CCW
Azimuth CW
Elevation DOWN
Elevation STOW
Elevation UP
Polarization CCW
Polarization CW
Polarization STOW
INTERLOCK LOGIC
Elevation movement below the Elevation DOWN position is not allowed unless the Azimuth STOW condition is active.
CCW movement in azimuth is not allowed when the azimuth CCW condition is active.
CW movement in azimuth is not allowed when the azimuth CW condition is active. No azimuth movement is allowed when the Elevation DOWN condition is active. No further elevation down movement is allowed when the Elevation STOW condition is active. NOTE: when the Elevation STOW condition is active, the RC3000 internally generates an Elevation DOWN condition.
No further elevation up movement is allowed when the Elevation UP condition is active.
CCW movement in polarization is not allowed when the polarization CCW condition is active.
CW movement in polarization is not allowed when the polarization CW condition is active.
Elevation movement below the Elevation DOWN position is not allowed unless the Polarization STOW condition is active. NOTE: only certain mounts mechanize the Polarization STOW limit switch – check appendix B for your mount.
Many problems are caused by limit switches either activating incorrectly or the RC3000 not sensing the limit switch’s state correctly. The following are some examples of problems caused by limit switch sensing:
Mount will move down in elevation but not up. Check that the Elevation UP limit switch is not stuck in the active state.
Mount will not move below the DOWN elevation limit. Check that the Azimuth STOW limit switch has activated correctly. Also check the polarization STOW limit switch if the mount is so equipped.
Mount will only move up in elevation. Check that the Elevation STOW limit switch is not stuck in the STOW condition.
Mount is above the Elevation DOWN position but will not move in azimuth. Check that the Elevation DOWN limit switch is not active.
Failure of a limit switch to activate properly may be due to the limit switch mechanism itself, cabling to the limit switch or failure of the RC3000 to sense the limit switch correctly. Isolating the problem to the RC3000 or switch/wiring may be accomplished by jumpering the appropriate pins on the J3 connector. NOTE: only the Elevation STOW/DOWN/UP, Azimuth STOW and Polarization STOW (if applicable) are mechanized via discreet limit switches – Azimuth CW/CCW and Polarization CW/CCW limits are mechanized differently and will be discussed later.
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