IFD-540 shutdown
Printed From: Avidyne
Category: Avidyne General
Forum Name: IFD 5 Series & IFD 4 Series Touch Screen GPS/NAV/COM
Forum Description: Topics on Avidyne's IFD 5 Series and IFD 4 Series Touch Screen GPS/NAV/COM
URL: http://forums.avidyne.com/forum_posts.asp?TID=804
Printed Date: 06 May 2025 at 11:41pm
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com
Topic: IFD-540 shutdown
Posted By: brou0040
Subject: IFD-540 shutdown
Date Posted: 07 Sep 2015 at 10:00pm
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I had my alternator voltage regulator fail on takoff this past Saturday.
The alternator went offline and the low voltage light came on. The IFD-540 went immediately black although the buss was still powered by the battery and all of the rest of the panel (including my AXP340) stayed online during that time. I understand the IFD-540 has shutdown protection if the power is beyond limits, but since the buss was still powered by the battery, I was surprised to see the 540 die. I was able to turn it back on during that flight and although it looked like it had a hard boot since it didn't bring up the last or local frequency, it eventually came fully online. I then powered it down in flight to reduce the load on the battery. I've sent the logs to tech support for them to review them and let me know why the 540 failed. I'll follow up and post their response here. Has anybody else seen this issue?
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Replies:
Posted By: oskrypuch
Date Posted: 07 Sep 2015 at 10:49pm
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What was the voltage on the bus when on ship's battery? There are specific limits outside of which the 540 will shutdown, they are in the manuals.
* Orest |
Posted By: brou0040
Date Posted: 07 Sep 2015 at 11:14pm
The battery was in good condition and charging prior to takeoff. I'm assuming it was very close to 24 volts, but I've sent the logs for Avidyne to verify. The manual says that a 60 second countdown starts when the voltage drops to 9 volts, I shouldn't have been anywhere near that low. Depending on the section of the manual, the minimum voltage for the AXP340, which stayed online is either 10 or 11 volts. I'm not sure what it does as the voltage falls below that level.
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oskrypuch wrote:Posted By: safari
Date Posted: 08 Sep 2015 at 12:07am
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I had mine shut down the other day when I was using it in the plane with the charger on it was kind of strange first time I have seen this. It rebooted by it self ------------- Dave |
Posted By: AviJake
Date Posted: 08 Sep 2015 at 12:16pm
Logs *should* tell us what your box was seeing for input voltage. For reference, here's a snippet from the pilot guide about behaviors as input voltage decrease:Low Power OperationsThe following actions are taken as input power is reduced to the IFD:
Function is restored by rising above those voltage thresholds by 1VDC for more than 1 second. ------------- Steve Jacobson sjacobson@avidyne.com |
Posted By: brou0040
Date Posted: 08 Sep 2015 at 3:11pm
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AviJake, Do you have any details of what the AXP340 does as voltage drops? It would be useful to compare why one stayed online and the other didn't.
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Posted By: AviJake
Date Posted: 08 Sep 2015 at 7:23pm
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I think I have some notes on that from a test I ran last year. I'll try to dig those up in the next few days when I get a few minutes and re-post. ------------- Steve Jacobson sjacobson@avidyne.com |
Posted By: MysticCobra
Date Posted: 09 Sep 2015 at 7:27am
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Clearly the IFD didn't follow the script in this particular case--nowhere on there does it say, "IFD immediately shuts off", which is what was observed. There may have been a transient voltage fluctuation that occurred when the alternator's voltage regulator failed. It would be interesting to understand the IFD's ability to tolerate (or not tolerate) such transients, as well as what it's supposed to do as voltage "gracefully" degrades as the ship's battery depletes.
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Posted By: AviJake
Date Posted: 09 Sep 2015 at 7:35am
I would not jump to that conclusion. Until we look at the logs, we will not agree that the IFD actually shut down. It could be a simple as the backlighting was turned down/off. When we can get the logs, we'll know. As for the AXP340 behavior, my notes from previous testing indicate: You need 10V to turn it on and it will display a "Low Output Power" alert message. Below 6V, it will shut off completely. The backlighting will hold steady before it goes completely dark.
------------- Steve Jacobson sjacobson@avidyne.com |
Posted By: MysticCobra
Date Posted: 09 Sep 2015 at 8:20am
| I was going by the OP's comment "I was able to turn it back on during that flight and although it looked like it had a hard boot since it didn't bring up the last or local frequency, it eventually came fully online," but fair enough--the logs should tell the true story. |
Posted By: brou0040
Date Posted: 09 Sep 2015 at 9:20pm
Tech support replied today saying they saw anomalies in the logs so they sent them to engineering. I'm waiting to hear what they find and what the anomalies were. As far as what I know, it went black as the alternator voltage controller (not the alternator itself) died on takeoff. Once I climbed to a safe altitude, I tried to restart it by simply pressing the power button and it started back up with what I'll call a "hard boot". I'd assume if the backlighting went down/off, that I would have had to hold the power button down for the countdown then press it again to turn it back on - I did not have to do that. The manual says that display lighting maximum values are reduced as voltage drops below 11.5VDC. Perhaps this is tied with the backlighting issue where even after calibrating the dimmer, it is still unviewable during the daytime (I hope and believe that increasing this max limit is in the next release). Perhaps it got so dim during the 60 second shutdown that I couldn't have seen it. I doubt this because I don't believe my buss voltage was below 9VDC for more than a minute, but was all of the sudden OK when I powered it back on at altitude.
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