REFLECTOR: Dynon Response -Oil Temp Sensor

Fri Sep 23 13:15:39 CDT 2011

BTW - one can use a floating ground Oil pressure sender as well.

I don't know if Dynon uses a floating ground pressure sender - perhaps they already do.

I believe GRT typically uses a VDO 360-004 sender for oil pressure, this can be replaced with a  VDO 360-430, which is the floating ground version.  Both of these are 1/8-27 NPT, 0-150psi.

John

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On Behalf Of Alex Balic
Sent: Friday, September 23, 2011 12:49 PM
To: 'Velocity Aircraft Owners and Builders list'
Subject: REFLECTOR: Dynon Response -Oil Temp Sensor

I had been in contact with Dynon to get them to support the Hall Effect
-type ammeter- like Grand Rapids (and Blue Mountain) used- they finally got
that supported today! And I asked the tech I was dealing with about the
Engine sensor problems that have been going around- they said that they had
just become aware of the issue, and they sent me this response:

Alex:

Here's our new write-up on grounding from the most recent SkyView System
Installation Manual:

Engine Sensor Accuracy and Grounding

It is vitally important that all engine sensors, your Dynon SkyView display,
your SV-EMS-220 module, and electrical system all share the same ground, and
that there is virtually no measurable voltage between these grounds.
Large currents flow between your alternator and the rest of your aircraft.
The ground for these currents is shared with your sensors. Because of the
large currents involved, resistance in grounds that cannot be seen with a
simple multimeter can still lead to significant voltage offsets. This can
lead to errors in sensor readings.

These large currents exist in other planes in the aircraft as well, such as
between the battery ground cable and its connection to the airframe, and
along the grounding points for the avionics bus. It is important that all of
these ground paths be appropriately sized for the loads involved, and that
the connections be clean, solid, and devoid of contamination.

In particular, be sure to connect a ground wire between your engine block or
avionics ground block and any of the SV-EMS-220's ground pins.

Please note that running a ground wire from the EMS to the engine block may
not entirely solve grounding issue, as this adds just a small wire in
parallel with another much larger wire, and the load will get transferred to
this smaller wire, which itself is resistive due to its small size, and thus
no real effect will be seen.

Though dealing with grounding issues can be time consuming and frustrating,
errors that are seen on your Dynon Engine Monitor are caused by points in
the aircraft where there is insufficient grounding. This can lead to weak
starting, hot wires, and corrosion. Fixing the Engine Monitor readings by
having a good ground will also lead to a healthier aircraft electrical
system overall.

Thanks,

Steve
Dynon Avionics Technical Support
email:support at dynonavionics.com
phone: 425-402-0433 - 07:00-17:00 Pacific weekdays

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Ruben Creus
Sent: Friday, September 23, 2011 12:26 PM
To: 'Velocity Aircraft Owners and Builders list'; 'Scott Derrick'
Subject: Re: REFLECTOR: Dynon -Oil Temp Sensor

Scott,

By the way, it is a resistor sensor so there is no polarity. One wire to the
Oil temp input and another to a ground. Just remember that the wire you will
connect to the ground should be connected to the ground system and not the
engine block or you will have the same issue. Ideally, the same ground line
where the Dynon is connected.

Hopefully this helps solving the issue for good.

Ruben

-----Original Message-----
From: Scott Derrick [mailto:scott at tnstaafl.net]
Sent: Thursday, September 22, 2011 1:38 PM
To: Velocity Aircraft Owners and Builders list
Subject: Re: REFLECTOR: Dynon -Oil Temp Sensor

Ruben,

Many thanks!!  I've been battling this since I installed the Dynon!

I will order the sensor today, $19 is very reasonable.

Scott

-------- Original Message --------
Subject: Re: REFLECTOR: Dynon -Oil Temp Sensor
From: Ruben Creus <ruben at vainneg.com>
To: 'Velocity Aircraft Owners and Builders list' <reflector at tvbf.org>,
'Scott Derrick' <scott at tnstaafl.net>
Date: 09/22/2011 11:20 AM

> Scott,
>
> Well, the sensor is made by Grand Rapids, which is a direct competitor of
> Dynon, so maybe they do not want to make so public to avoid admitting that
a
> competitor had a better solution for an oil temp device. Anyhow, they
> finally told me that this should work. I tried it and since is just going
> perfect!
>
> NOTE: Remember that if you use this sensor you need to change the oil temp
> sensor type in your Dynon configuration to TYPE 3
>
>
> Here is the info of the sensor
>
> Part Number: GRT FT-LC-01
>
> I bought it from Chief. Here is the link.
>
>
http://www.chiefaircraft.com/avionics/grand-rapids/optional-replacement-part
> s/grt-ft-lc-01.html\
>
> Price $19
>
> Hope that helps.
>
>
> Ruben Creus
> 571-215-0025
> ruben at vainneg.com
>
>
>
> -----Original Message-----
> From: Scott Derrick [mailto:scott at tnstaafl.net]
> Sent: Wednesday, September 21, 2011 8:24 PM
> To: Velocity Aircraft Owners and Builders list
> Subject: Re: REFLECTOR: Dynon -Oil Temp Sensor
>
> Rueben,
>
> I've been dealing with the exact same problem!  I wonder why they didn't
> mention a two wire sensor to me?
>
> Do you have the part number?
>
> Thanks
>
> Scott
>
> Ruben Creus<ruben at vainneg.com>  wrote:
>
>> Hi all,
>>
>> I have been dealing with a problem for a long time with the reading of my
>> oil temp in my Dynon, and finally found a solution. So, I thought to
share
>> it around in case anyone else has the same issue with a Dynon unit.
>>
>> I have a Dynon flightDeck-180, and always had the issue of seeing my oil
>> temp fluctuating based on the current of the alternator. I originally had
a
>> 1-wire oil sensor, the sensor was grounded on the engine block. That
> created
>> small a ground differential between the back and the nose of the plane
>> translating on a variation of the displayed temperature of approximately
> +10
>> degrees, the Dynon was grounded in the nose and the sensor in the engine
>> block.
>>
>> Talking with Dynon, about it they told me to change the oil temp sensor
to
> a
>> 2-wire sensor. First, the resolution of the sensor is ten times greater,
so
>> it is more accurate, and second, the second wire can connect directly to
> the
>> ground of the harness, virtually bringing the ground to the sensor to the
>> ground of the Dynon.
>>
>> Previously I had jumps of 10 degrees when I pushed my PTT, or turn on
>> landing light, or when the alternator was giving more current for any
>> reason.
>>
>> Now the result is that variations have disappeared. Now the oil temp does
>> not suddenly fluctuate anymore!!
>>
>> Ruben Creus
>> 571-215-0025
>> ruben at vainneg.com
>>
>>
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