Servos are initially detected and calibration accomplished. Then at some point one or both servos show going off line. Have checked for loose wiring and nothing found. Did have the thought that the transponder antenna wiring was in close proximity. Tried rerunning antenna wire away but problem persists. I am able to get the servos working with transponder in standby but when turned on the Servos go off line. Turn transponder off, turn servos off and then on and they come back on line. Any suggestions as a remedy?
Servos go off line
- Thread starter Doug.Kan
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andresmith76
I love flying!
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- Oct 4, 2018
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How close is the transponder antenna to the servos? From your description, it does sound like energy from the transponder is creating interference, causing the servos to go off-line.
Rhino
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- Jul 20, 2009
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Going offline is a serial bus thing. That may or may not be caused by the actual serial bus itself. But servos aren't exactly known for being prone to outside interference. And because one of your servos apparently doesn't coexist with transponder wiring, interference from the transponder is less likely. I'd try the interference angle first, because it's relatively easier to troubleshoot. But if that doesn't pan out, it's possible the data travelling over the serial bus when you take the transponder out of standby, is causing other serial bus units, servos in your case, to go offline. That suggests a possible problem with the serial bus wiring to the transponder, which begs another question. Did you buy a prebuilt transponder wiring harness, or build your own?
I have an AFS EFIS and experienced something similar when I replaced Trutrak servos with Dynon. Even though the Dynon manual states to use twisted pair for the SV-net connection, I attempted to use the existing SteinAir harness that the Trutrak servos used.
I had similar symptoms. All three servos could be configured and calibrated individually. When just roll and pitch were engaged, they worked normally. As soon as I engaged the yaw servo, the whole AP systems was disabled. It took rebooting the EFIS bring the AP system back online.
after quick a few troubleshooting tests, it was resolved by installing new twisted pair wiring. The original SteinAir harness for the Trutrak servos simply have the whole wire bundled twisted, but not the two pairs of wires for the SV-net connection. I still don’t understand why the third servo being engaged caused the issue, but only that wiring it per the instructions resolved the issue. I would have thought if there was an rf interference issue it would have shown up with just the two servos engaged.
I'm not implying that this may be your issue, but would recommend checking that the two pairs of wires for the SV-net are indeed twisted.
I had similar symptoms. All three servos could be configured and calibrated individually. When just roll and pitch were engaged, they worked normally. As soon as I engaged the yaw servo, the whole AP systems was disabled. It took rebooting the EFIS bring the AP system back online.
after quick a few troubleshooting tests, it was resolved by installing new twisted pair wiring. The original SteinAir harness for the Trutrak servos simply have the whole wire bundled twisted, but not the two pairs of wires for the SV-net connection. I still don’t understand why the third servo being engaged caused the issue, but only that wiring it per the instructions resolved the issue. I would have thought if there was an rf interference issue it would have shown up with just the two servos engaged.
I'm not implying that this may be your issue, but would recommend checking that the two pairs of wires for the SV-net are indeed twisted.