Today's Message Index:
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1. 02:03 AM - Re: Info on MGL Enigma (Jay Hyde)
2. 06:45 AM - Re: Info on MGL Enigma (Robert L. Nuckolls, III)
3. 07:45 AM - Re: Info on MGL Enigma (Robert L. Nuckolls, III)
4. 10:27 AM - Bonding Straps (stearman456)
Message 1
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| Subject: | Info on MGL Enigma |
Here is the reply from Rainier, the owner and founder of MGL:
The CR2032 battery is only used to maintain items that change frequently
like calculated fuel levels, local pressure settings etc.
Setup is stored in a flash memory section of a secondary processor chip
in the EFIS. This does not need a backup battery.
If setup data stored here is not maintained there is usually only one
cause: The supply voltage to that processor is raised briefly
(micro-seconds to mill-seconds) above about 8V. This can happen if the
supply to the EFIS contains sharp voltage spikes (typically caused by
bad regulators or high voltage ignition is coupling into ground or
supply). This can also happen if there are static discharges typically
caused by airflow over metal parts that are not grounded.
Eventually, this will damage the flash memory which is the part that
dies first in our experience.
When this happens we replace the processor chip. If you have a techie
handy - it is a type ATMEL ATMega128. It is a SMD package but easy to
solder/desolder if you have the experience. Once replaced I would also
recommend replacing the 16Mhz crystal right next to this chip - it tends
to wear out over a long time (we replace these as a matter of course
when we get an Enigma in for repairs). No specific programming of the
new processor needs to be done as the firmware will detect a new
processor and do the programming and setup of this chip automatically
(the first start-up will take a bit longer and you will see some
messages on the display to this effect).
Rainier
--
MGL Avionics
Postal:
Postnet Suite X15
Somerset West 7129
South Africa
Physical:
5 Fuchsia street
Somerset West 7130
South Africa
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
HH Enterprises
* Aircraft assembly, repair, wiring and avionics
* Flight instruction
* General and Electrical Engineering services
(NHD Elec Eng, BTech Elec Eng, GDE ELec Eng)
* Great dinner parties and conversation
* General adventuring, climbing, kayaking and living
Blog: www.rawhyde.wordpress.com <http://www.rawhyde.wordpress.com/>
Cel: 083 300 8675
Email: jay@horriblehyde.com
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of
Charlie England
Sent: 31 May 2014 01:20 AM
Subject: Re: AeroElectric-List: Info on MGL Enigma
On 5/30/2014 5:25 PM, Richard Girard wrote:
While trying to fathom why the CHT readings on the MGL Enigma EFIS had
stopped on my friend's Rotax 912 powered JA Highlander I delved into the
manual for the EFIS and its RDAC unit (the box that all senders report
to before their data is passed along to the EFIS).
On page 6 or so of the RDAC manual there is a picture of the back of the
Enigma with a note that the battery under a rectangular cover should be
changed every two years. Upon removing said cover I discovered a CR2032
lithium battery. I checked its voltage output and found it to be 2.9
volts. A new one that the aircraft owner just happened to have in his
tool kit (he maintains medical equipment for a living) put out 3.3 volts
so we replaced the old one.
More investigation into the setup menus for EFIS revealed that there is
an option for a Rotax sender for the CHT setup and when we checked the
unit we found it had reset to a J type thermocouple. Resetting it to the
Rotax sender solved the problem and the EFIS began reporting good CHT
values.
Curious to find out if the low output of the CR2032 was responsible for
the glitch in the CHT setup I delved into the manual for the EFIS and
could find no reference to it in the manual's table of contents, index,
or during a long skim of its contents. The same was true of the RADC
manual with the exception of the picture and note mentioned earlier.
Now we find that the same thing has happened to the oil pressure
reading. Again the setup has been changed to reflect a different type of
sender, only this time restoring it to the Rotax sender option has not
fixed it. There are two sender options for each of resistive type
senders and voltage type. On either resistive option (the Rotax option
is a resistive sender) the bar graph on the EFIS locks up and does not
read. When I set it to either of the voltage type it then reads but it
reads backward, i.e. as the engine revs up the reading drops and vice
versa.
The oil pressure sender is a VDO unit and I have located it in VDO's
technical offerings online. VDO recommends that the sender be installed
dry with no teflon tape or thread sealant so that it will ground
properly so we have an investigative path when we return to the airplane
this weekend.
MGL has taken the Enigma technical info off line and the aircraft's
owner has not been able to find any information on the CR2032 battery as
to what it does or how to change it properly.
Does anyone out there know about it?
Thanks,
Rick Girard
It isn't necessary to have relatives in Kansas City in order to be
unhappy.
- Groucho Marx
I can't help with specific info on the MGL, but using that battery for
'backup' is fairly common in electronics. If you use a desktop PC, odds
are good that there's one on the motherboard. My old Garmin III Pilot
gps has one in it. (Note that they make that case style in both a
lithium 'primary' battery, and a lithium rechargeable battery, & it's
sometimes difficult to tell which the mfgr is using.) In the
applications I've seen, the battery keeps a CMOS memory alive, and
that's where basic configuration settings are stored in a lot of
devices. If the battery goes too low to keep the CMOS memory active, the
device will forget whatever settings were stored there. I would think
that more current tech, especially in an a/c device, would avoid using
CMOS memory & the required battery, but some really high dollar avionics
still use it.
On many PC's, if the battery dies, after battery replacement you
sometimes have to do a 'hard reset' by shorting a pair of pins on the
motherboard to completely clear the CMOS memory before re-entering all
the parameters needed.
Sounds like it's time for a Skype call to S Africa. :-)
Charlie
Message 2
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| Subject: | Info on MGL Enigma |
At 04:02 AM 6/2/2014, you wrote:
Here is the reply from Rainier, the owner and founder of MGL:
The CR2032 battery is only used to maintain items
that change frequently like calculated fuel
levels, local pressure settings etc.
Setup is stored in a flash memory section of a
secondary processor chip in the EFIS. This does not need a backup battery.
If setup data stored here is not maintained there is usually only one
cause: The supply voltage to that processor is
raised briefly (micro-seconds to mill-seconds)
above about 8V. This can happen if the supply to
the EFIS contains sharp voltage spikes (typically
caused by bad regulators or high voltage ignition
is coupling into ground or supply). This can
also happen if there are static discharges
typically caused by airflow over metal parts that are not grounded.
Eventually, this will damage the flash memory
which is the part that dies first in our experience.
When this happens we replace the processor chip.
If you have a techie handy - it is a type ATMEL
ATMega128. It is a SMD package but easy to
solder/desolder if you have the experience. Once
replaced I would also recommend replacing the
16Mhz crystal right next to this chip - it tends
to wear out over a long time (we replace these as
a matter of course when we get an Enigma in for
repairs). No specific programming of the new
processor needs to be done as the firmware will
detect a new processor and do the programming and
setup of this chip automatically (the first
start-up will take a bit longer and you will see
some messages on the display to this effect).
I am exceedingly skeptical of these assertions.
I don't know of a single 5v regulator offered to
the task of conditioning power for electronics
that doesn't handily mitigate any of the commonly
known variables on the ship's bus. DO-160 offers
a clear and concise path to living confidently
in the world of DC powered vehicles.
Crystals that 'wear out'?
Static discharges ? ! ? ! . . . again, for any
piece of hardware to be qualified for installation
on a TC aircraft, it has to be capable of withstanding
discharges of a 150pF capacitor through 330 ohm
resistor fed directly to every input/output pin
on the device under test. TEN times for positive
spikes, TEN more times for negative spikes.
Sound brutal . . . but the components and architecture
for designing to this level of stress is rudimentary
and has been as common to the designer's toolbox as
a hammer is to a carpenter's toolbox. I quit doing
the test 25 years ago after learning what it took
to pass . . . easily . . . every time.
If the stresses cited are genuine risks to MGL's
products, then they've failed to understand
and embrace the real world stresses found in
mobile DC powered system of all stripe . . . not
the least of which are airplanes.
Bob . . .
Message 3
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| Subject: | Info on MGL Enigma |
At 04:02 AM 6/2/2014, you wrote:
Here is the reply from Rainier, the owner and founder of MGL:
The CR2032 battery is only used to maintain items
that change frequently like calculated fuel
levels, local pressure settings etc.
Setup is stored in a flash memory section of a
secondary processor chip in the EFIS. This does not need a backup battery.
If setup data stored here is not maintained there is usually only one
cause: The supply voltage to that processor is
raised briefly (micro-seconds to mill-seconds)
above about 8V. This can happen if the supply to
the EFIS contains sharp voltage spikes (typically
caused by bad regulators or high voltage ignition
is coupling into ground or supply).=C2 This can
also happen if there are static discharges
typically caused by airflow over metal parts that are not grounded.
Eventually, this will damage the flash memory
which is the part that dies first in our experience.
When this happens we replace the processor chip.
If you have a techie handy - it is a type ATMEL
ATMega128. It is a SMD package but easy to
solder/desolder if you have the experience. Once
replaced I would also recommend replacing the
16Mhz crystal right next to this chip - it tends
to wear out over a long time (we replace these as
a matter of course when we get an Enigma in for
repairs). No specific programming of the new
processor needs to be done as the firmware will
detect a new processor and do the programming and
setup of this chip automatically (the first
start-up will take a bit longer and you will see
some messages on the display to this effect).
I am exceedingly skeptical of these assertions.
I don't know of a single 5v regulator offered to
the task of conditioning power for electronics
that doesn't handily mitigate any of the commonly
known variables on the ship's bus. DO-160 offers
a clear and concise path to living confidently
in the world of DC powered vehicles.
Crystals that 'wear out'?
Static discharges ? ! ? ! . . . again, for any
piece of hardware to be qualified for installation
on a TC aircraft, it has to be capable of withstanding
15KV discharges of a 150pF capacitor through 330 ohm
resistor fed directly to every input/output pin
on the device under test. TEN times for positive
spikes, TEN more times for negative spikes.
Sound brutal . . . but the components and architecture
for designing to this level of stress is rudimentary
and has been as common to the designer's toolbox as
a hammer is to a carpenter's toolbox. I quit doing
the test 25 years ago after learning what it took
to pass . . . easily . . . every time.
If the stresses cited are genuine risks to MGL's
products, then they've failed to understand
and embrace the real world stresses found in
mobile DC powered system of all stripe . . . not
the least of which are airplanes.
Bob . . .
Message 4
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In a mixed construction airplane (steel tube fuselage, wooden wings, aluminum structure
flight controls, everything fabric covered) what would the down side
be in not having everything electrically bonded? My electrical system is a two
wire, 14v system with everything running to a "forest of tabs" ground bus on
the firewall. The avionics (SL40 com, GTX 327 txdr) run to their own, dedicated
ground bus which in turn is wired to the firewall ground bus. I'm doing the
bonding per the original design, but I'm just curious. Would all the various
assemblies of the airplane create static charges that would cripple the radios?
Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=424217#424217
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