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| FAULT FINDING |
If all the angles are changing the fault is on the Interface PCB.
wrong angle displayed If the displayed angle changes to be near 0° or 90° it is probable that one of the two return signal circuits from the resolver is broken or the resolver itself is faulty.
If the displayed angle changes to any angle other than near 0° or 90° the fault is on the Interface PCB.
angle doesn’t change If the displayed angle doesn’t change when the antenna is
when antenna is moved being driven first ensure that the antenna is actually moving in the relevant plane. Select Manual Mode and drive the antenna in the appropriate direction and either check that the beacon level changes or actually look at the antenna.
If the antenna moves but the displayed angle does not change the problem is the connection of the resolver to the antenna.
No Antenna Drive | Check that the LEDs in the Manual Control keys illuminate |
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| when antenna drive is commanded. If not the fault is on the |
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| Interface PCB. |
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| The Motor Controls connector |
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| rear panel outputs +12v and ground to for each drive signal. |
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| The +12v and ground levels are switched to the approriate |
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| pins of the connector by relays. One relay switches +12v for |
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| all Az drive commands, another does so for all El drive |
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| commands and a third for Pol drive. The ground level is |
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| switched by changeover relays, one does Az West or East, |
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| another Az Fast or Slow, another El Down or Up, another El |
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| Fast or Slow and another for Pol CCW or CW. |
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| The table below indicates across which two pins of the 50 |
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| way connector there should be 12v for each drive condition. |
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| Direction |
| Az | Az |
| Az | Az | El |
| El | El | El |
| Pol | Pol |
| & Speed |
| East | West |
| Fast | Slow | Down |
| Up | Fast | Slow |
| CCw | Cw |
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| +12 volts |
| 18 | 19 |
| 20 | 21 | 22 |
| 23 | 24 | 25 |
| 26 | 27 |
| Ground |
| 1 | 2 |
| 3 | 4 | 5 |
| 6 | 7 | 8 |
| 9 | 10 |
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| example | Elevation Up Fast - | there should be 12v across pins 23 & 6 |
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| (El Up) and across 24 & 7 (El Fast). |
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If the drive signals from the INTRAC are correct the fault lies with the Motor Drive Cabinet, the antenna drive motors or the intervening wiring.
© Advantech Wireless | Page 81 |