What's the specific issue? Can you provide a link to the post?
oil temp fluctuation
- Thread starter Roger_Lee
- Start date
Hi Dynon,
The D120's oil temp would fluctuate 4-10F as I reported on the first of this thread. It was a software issue. Your programmers came up with a Beta fix to try and sent it to 3 of us. It works like a charm. My oil temps now are stable. here is a copy attached below. I have tried it in a dozen planes, it works well. It is an EFS file extension so it is in a winzip file.
We have another issue with the ammeter fluctuating with the Rotax. I sent a fix in to the programmers, but they haven't done anything with it yet.
The D120's oil temp would fluctuate 4-10F as I reported on the first of this thread. It was a software issue. Your programmers came up with a Beta fix to try and sent it to 3 of us. It works like a charm. My oil temps now are stable. here is a copy attached below. I have tried it in a dozen planes, it works well. It is an EFS file extension so it is in a winzip file.
We have another issue with the ammeter fluctuating with the Rotax. I sent a fix in to the programmers, but they haven't done anything with it yet.
Yes. It's basically the only other change that will be in the update.
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- Mar 23, 2005
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- 13,226
Roger,
The oil temp issue is an actual software bug where no filter was being used.
The ammeter issue is much more complicated and is not something we can fix in software. I know that a while ago you requested we add "a moving average filter with a 2 second time constant". Is this what you mean by you sent a solution to us?
We already have a filter on the ammeter, and always have. Believe it or not, the numbers you are seeing are seriously reduced by the filter that is in place.
The issue is the noise is much faster than our sample rate.
Imagine you have a signal which is supposed to be 20A. But imagine it's 10A half the time and 30A the other half because of the noise on it. The average is 20A, but at no point is it actually 20A.
Now, take samples of this every now and then. It's actually possible that you just take samples when it's 30A, and no filtering in the world will make that 20A. Digital systems don't look at the voltage 100% of the time, so they don't get to run a perfect average.
So this gets deep into sampling theory and averaging methods, and the simple answer is that we sample at 4Hz, and if your noise is large and faster than this, there is no software average that can help you.
About all we could do is put in a REALLY long filter but then that would block real issues (like when the alternator fails).
The oil temp issue is an actual software bug where no filter was being used.
The ammeter issue is much more complicated and is not something we can fix in software. I know that a while ago you requested we add "a moving average filter with a 2 second time constant". Is this what you mean by you sent a solution to us?
We already have a filter on the ammeter, and always have. Believe it or not, the numbers you are seeing are seriously reduced by the filter that is in place.
The issue is the noise is much faster than our sample rate.
Imagine you have a signal which is supposed to be 20A. But imagine it's 10A half the time and 30A the other half because of the noise on it. The average is 20A, but at no point is it actually 20A.
Now, take samples of this every now and then. It's actually possible that you just take samples when it's 30A, and no filtering in the world will make that 20A. Digital systems don't look at the voltage 100% of the time, so they don't get to run a perfect average.
So this gets deep into sampling theory and averaging methods, and the simple answer is that we sample at 4Hz, and if your noise is large and faster than this, there is no software average that can help you.
About all we could do is put in a REALLY long filter but then that would block real issues (like when the alternator fails).
Folks,
The build at this link:
5.5.RC2
Includes the fix for the fluctuating oil temp on Rotax engines. Those who were testing with sensor "11" should go back to sensor "4". Again, this is for the oil temp sensor that comes with Rotax engines only. If you have any other sensor, choosing sensor 4 will cause your oil temperature readings to be wrong.
This version also includes a number of autopilot changes, which address NAVSRC LOST dropouts and some sensor calibration. In particular, the following applies:
While in ALT hold, after 5-10 min in altitude hold in smooth air, it will self-calibrate out any altitude offset error that the AP has exhibited for some people. There will be a positive bump to your assigned altitude.
Also, This version also addresses the tendency to climb when the ball is not centered.
As always, be sure to make a backup before you upgrade.
Let us know if you have any questions.
The build at this link:
5.5.RC2
Includes the fix for the fluctuating oil temp on Rotax engines. Those who were testing with sensor "11" should go back to sensor "4". Again, this is for the oil temp sensor that comes with Rotax engines only. If you have any other sensor, choosing sensor 4 will cause your oil temperature readings to be wrong.
This version also includes a number of autopilot changes, which address NAVSRC LOST dropouts and some sensor calibration. In particular, the following applies:
While in ALT hold, after 5-10 min in altitude hold in smooth air, it will self-calibrate out any altitude offset error that the AP has exhibited for some people. There will be a positive bump to your assigned altitude.
Also, This version also addresses the tendency to climb when the ball is not centered.
As always, be sure to make a backup before you upgrade.
Let us know if you have any questions.
Just a quick note that the final 5.5 software has been released. Fixes the Rotax oil temp fluctuations, AP NAVSRC lost messages, and a couple of other very minor AP annoyances. There are no new features in this release. This release does not apply to D6/D60 (the firmware for those products is unchanged). You can grab the update at http://www.dynonavionics.com/docs/support_software.html
Hi, l just saw this mention of sensor type 9!! I had given up on my Dynon equipment as l was disgusted by the lack of back up in the uk
I have personally fitted a manual temp gauge. So at this time l am still waiting for some kind of solution..l should add that many of the readouts are unstable on both my units and have been that way from new.
Forget about sensor type 9 - that was in the beta software only for testing. In the actual release version, it's sensor type 4, as specified in the manual.
Admittedly our D10/D100 series products don't have the most intuitive update method. Danny at Harry Mendelssohn in the UK should be able to help you update your unit if you can get your unit there. Give him a call before sending it though.
Admittedly our D10/D100 series products don't have the most intuitive update method. Danny at Harry Mendelssohn in the UK should be able to help you update your unit if you can get your unit there. Give him a call before sending it though.
dodsond
New Member
- Joined
- Aug 9, 2006
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- 76
I have the fluctuating oil temp problem on my Lycoming engine. I have had it since day 1. Occasionally a CHT or EGT will do this but a reset of the spade connectors fixes it, at least for a while. I have tried lots of ways to better ground the oil temp probe with no luck.
I have two (and a half) questions:
Can I use UMA 3TB3 or 3TB3-2.5 in place of 1B3 for the oil temp? The wires are much more robust. I know they all three fit the engine.
Can I use screw terminals on the CHT/EGT probes like JPI? Why not just splice the wires?
TIA
I have two (and a half) questions:
Can I use UMA 3TB3 or 3TB3-2.5 in place of 1B3 for the oil temp? The wires are much more robust. I know they all three fit the engine.
Can I use screw terminals on the CHT/EGT probes like JPI? Why not just splice the wires?
TIA
Which of our products do you have?
For CHTs/EGTs, the only requirement is that the CHTs be type J thermocouples, and the EGTs be type K thermocouples. The form factor doesn't matter, but I'm not famiar with whether the screw terminal probes you're talking about are thermocouple-based.
On the oil temp - your engine (which is how the oil temp probe is grounded) needs to have a REALLY big ground to the rest of the electrical system (the negative side of the battery / avionics bus / etc). Note that running a small but direct line anywhere won't do the trick - the grounding between the engine and everything else needs to be substantial.
On the oil temp - your engine (which is how the oil temp probe is grounded) needs to have a REALLY big ground to the rest of the electrical system (the negative side of the battery / avionics bus / etc). Note that running a small but direct line anywhere won't do the trick - the grounding between the engine and everything else needs to be substantial.
jakej
Well-Known Member
The screw type are typically what JPI or EI uses but star washers must be used between the ring terminals & under the head of screws & under the nuts.
Doug - I'd use a good size braided earth strap as well as a 1/4" braid to the Dynon case, just to be sure.
I'm giving my FT a major makeover (2028 hrs TT now) & installing a dual Skyview system however I had a VMS800 system without any Oil Temp issues so I expect not to with the Dynon, it's all in the grounding IMO
Jake J
Doug - I'd use a good size braided earth strap as well as a 1/4" braid to the Dynon case, just to be sure.
I'm giving my FT a major makeover (2028 hrs TT now) & installing a dual Skyview system however I had a VMS800 system without any Oil Temp issues so I expect not to with the Dynon, it's all in the grounding IMO
Jake J
dodsond
New Member
- Joined
- Aug 9, 2006
- Messages
- 76
I have a strap from the engine to a metal panel all my firewall electrical components are fastened to. There is an 8ga wire connecting that panel to a brass ground buss in the cockpit, and a strap connecting the panel to the battery. That panel is also the ground point for a wire I strapped to the oil temp sensor body.
I have previously removed the oil temp probe to scrape the paint off the engine case where the probe seats. All with no luck. That is why I wanted to try a 2 wire probe. The T3B3 UMA probe has steel braided wire leads like the EGT probes which I like much better, so that is why I was asking if it would work like the UMA 1B3.
I don't want new EGT/CHT probes, I just want to replace the connectors because individual probes go intermittent periodically and the fix is re-seating the connector. That fixes it, but not forever. I thought a more secure connector might do the trick.
I am not sure what size wire I used to ground the D-120 case, but it has a dedicated wire to the brass ground buss.
I have previously removed the oil temp probe to scrape the paint off the engine case where the probe seats. All with no luck. That is why I wanted to try a 2 wire probe. The T3B3 UMA probe has steel braided wire leads like the EGT probes which I like much better, so that is why I was asking if it would work like the UMA 1B3.
I don't want new EGT/CHT probes, I just want to replace the connectors because individual probes go intermittent periodically and the fix is re-seating the connector. That fixes it, but not forever. I thought a more secure connector might do the trick.
I am not sure what size wire I used to ground the D-120 case, but it has a dedicated wire to the brass ground buss.
So there are other sensors that you can use - I believe the UMA 1B9 series, which is supported, is a two wire probe that would work (doesn't use the sensor case as the ground path). Also, the GRT oil temp sensor is supported for legacy installations, and that's also a two-wire probe. If you go to the sensor input mapping section of the EMS setup menu, you can go to the oil temp line and select the sensor name as if you were going to change it in order to get a list of all the supported oil temperature sensors.
704ch
I love flying!
Hi Dynon, Not sure if I should start a new thread, but I am running a Lycoming with a huge ground strap directly and securely between the engine and the ground on battery. Also have had no issues with my CHTs fluctuating, but my oil temp has fluctuated fairly dramatically since day one.
I can kind of get an idea if it is in the 160's-180's or so, but it always is up or down several times a second, and sometimes will even shoot down to 120's.
Any thoughts on this, or formal responses? This thread mainly deals with Rotax, so I wanted to follow up on Lycoming.
My engine is grounded securely.
Thx
I can kind of get an idea if it is in the 160's-180's or so, but it always is up or down several times a second, and sometimes will even shoot down to 120's.
Any thoughts on this, or formal responses? This thread mainly deals with Rotax, so I wanted to follow up on Lycoming.
My engine is grounded securely.
Thx