MobiFlight Community Support

Hello everyone, I have created Altimeter with two 7-segment display and a stepper motor.
All of this works in X Plane 11.
Unfortunately, after the launch, Mobi shows everything OK, but in a moment, one particular display will go out. The data it shows is correct.
To see the illuminated display again, I must restart Mobi. Do not you know someone in trouble?
Thank you Peter

Hi

Sorry i can´t help directly....

I can´t see what the "two ???" Displays should show !
So i can´t tell you if there is a issue in the config logic or a hardware problem.

Basic help:

Check the Mobiflight Connector Window while running your sim.
The Configs that controll your Displays ( two Display - two configs i think) have 2 collums to the right ( FSUIPC Value and Mobiflight Value)

Please check this values.... the Right Value should be shown on your Displays. If there is for example "2000" but Display show nothing then you have a Hardware Issue OR you have set the wrong Diggits in the Display Tab.

Another way to check this is using the TEST Button in the specific Config ( Display Tab) ( NOT the Test Button in Main Window)
STOP Mobiflight ( Get sure the RUn Button is not active) Open that configs and press this TEST Button.... If Display work fine then there must be shown 12345678 ( Or less if you use less diggits) .
If this is NOT showed then your Displays/Maxchip or Wirework is broke !

*****
Check this facts.... If hardware is Ok we need to recheck your configs. Then i need more information finaly!

Hello one display (top) shows 5 numbers and it's altitude in Feet, second (bottom) shows 4 numbers and QNH and stepper shows the feet on a circle.
Connection:
Stepper - PIN 39,41,43,45
offset 3324, Compas mode
Display Feet :
DIn 51, CS 49, CLK47 , NUM 1
offset 3324, INT, 4Byte
5 digits, USE left Padding 1,0
display QNH :
DIN 22, CS 24,CLK 26 , NUM1
offset 0330, INT,Byte 2, Interpolation 16211- 1013 Hpa
display 4 digits, left padding 1,0
the disply Feet test is Ok - 12345
I start the Mobi and try the test, all OK, the stepper turns, the display lights up, I give the RUN and the lights, I stop the STOP all goes out, I turn the RUN on, the STOP goes out, the RUN is on and then the STOP stops. not all 5, but only 1 and not one. Everything refers to the 5-digit Feet display, if I restart MOBI, it all works again. During the flight everything works for a while and then the FEET display goes out, the others are driving.
I still thought, try another display, but I have no replacement, I would have to use the one on QNH.
They are display with MAX7219 chip bought in a piece.
Peter

Hi

Summary i think your problem is on Hardware side....

Your Configs sounds ok. ( Whatever a bit difficult ) I would make it in another way. But this should not occure in your reported Error.

Please confirm your Displays are Solder.... Especialy if you use just jumper wires for example for the DIN CLK CS ports a little touching of system can occure in a Error and Mobiflight must be reseted ( Also the Boards) .

For Config:
In The QNH Config th interpolation is not good. I recommend here to work with a Transfom if needed.

In the Altitude Needle you can have a Problem if you stop Sim quickly..... For Example if Altitude is 15000 ft at the moment then your Stepper normaly must turn 15 times backwards ( Not use Compass Mode in that case)
Maby solution is here using of MODULO.... Transform "$%1000" This change a value like 15500 ft into 500 . Summary your Stepper got a Value like Sim1000/Stepper 2048
With active Compass mode this should be work. ( Not tested)

The Altitude Display sounds nice.

******
so.... I would check the Displays. Sometimes (20% of cases) those Chineese Displays are not perfect build and have issues. Then a resolder of Pins mostly fix the problem !

At the interconnection I used dupont pins and solder them. And then I used dupont cables.
To configure: QNH I was not able to configure the other way when I was thinking of adjusting the FSUIPC output and assigning QNH to it, another way you know?
And the same thing with the stepper, fortunately I fly VFR and at low altitudes. Even so, I suddenly had a negative height at the change of QNH, I do not know. For a stepper, I would only need to spin around the feet from 0 to 1000, basically a stepper should not show ten thousand feet or more, there's a display there. And thank you Peter

Yes... a Stepper in your case should not "see" all over 1000 feet ....
But with your config it will do, cause the value you use is the Full altitude 3324 .
If you climb for example from 0 ft to 3000 ft the needle turns 3 times .... But it finaly show the value of Offset and that is 3000 . If you stop Mobiflight at this point it must turn 3 times ccw to reach the zero Point. Your needle just show hundrets but internal it also count the thousends.

Please stay tuned.... I will check this in ym Holliday if i find time next 2 weeks. I think compas mode should work but can not garantee.

****

About QNH. FSUIPC says

Altimeter pressure setting (“Kollsman” window). As millibars
(hectoPascals) * 16

So a transform $/16 should result in a clear correct QNH hP.

About negative altitude.
Thats cause you use the Recalculated altitude from 3324 (Barometric.... Not Radio)
If you are on a Airport at Sea Level but your QNH is not set correct to the current Outside pressure then your altitude can be negative (Whatever you are on Ground or in a low flight)
If i´m right this offset show you ALT over Sea Level with current QNH Setting.

Hi together!

For air pressure measurement:

QNH is the abbreviation for Question Normal Height. This is the sea level atmospheric pressure of the measuring station. If the QNH is set on the altimeter, it will display the height of the airfield as altitude.

The opposite would be the QFE (Question Field Elevation). If the altimeter is set to 0 ft, the local air pressure can be read from it.

For international air traffic, the ICAO (International Civil Aviation Organization) has declared the QNH binding.

Therefore, it is understood that controllers indicate the QNH on the radio at each opportunity. The information is always to be read back.

There are two more special features. This is the Transition Altitude and the Transition Level.

For airspaces, the transition Altitude is usually set. This is usually 5,000 ft. In the US, it's 18,000 ft. This is the altitude after you have started to switch to the standard international atmosphere to the standard air pressure (1013.25 hPa).

Theoretically, here start the flight levels and all aircraft that fly at this altitude or above, must set the standard atmosphere on the altimeter.

The transition level is for those planes that want to land down from high altitudes (ie the heights of the flight levels).
Transition levels are FL50, FL60, FL70 and rarely FL80 (announced in the ATIS - depending on the local air pressure). If an aircraft reaches this flight level, it must be switched to QNH!

Easy to remember: when starting Transition Altitude (switch to standard atmosphere), when landing TransitionLevel (switch to QNH).

If you park your aircraft at 1000 hPa (QNH) in the evening and the air pressure changes overnight, you can read this off on the altimeter. Suppose the height of the airfield was 180 ft in the evening and the air pressure drops until the next morning, for example 10 hPa, the altimeter displays 240 ft more (420 ft). If the air pressure rises 10 hPa overnight, the altimeter will display 240 ft less (-60 ft).

Old pilot rule: from high to low, that goes awry

For airspaces, the transition Altitude is usually set. This is usually 5,000 ft. In the US, it's 18,000 ft.

The transition level is for those planes that want to land down from high altitudes (ie the heights of the flight levels).
Transition levels are FL50, FL60, FL70 and rarely FL80 (announced in the ATIS - depending on the local air pressure). If an aircraft reaches this flight level, it must be switched to QNH!

Just to avoid confuison....
This values are for Europe (Standard procedure) ..... for US Airspace there is a TL of FL180 until FL210

Basicly the Transition Layer ( The marge between TA and TL ) is 0ft in perfec Wether conditions and can be up to 3000ft in bad conditions.

I'm still returning to the use of 7 Segmented Displays. Yesterday I tried sim and I made 3 circuits to the airport, the display with feet worked and then at 4 circuit again only one number and in no time. Display with QNH works, stepper works. Then rerstart MOBI and again everything works, I'm crazy about it ???
Peter

hhhm.

Lets do it another way.

Do i understand right that you use those original Max Tubes with 8 Diggits for this test ?
If yes the follow procedure is easy... If not and you have a real 5 and 4 Diggit Setup then it workes, too but look a little strange.

****
Simply change the Displays for testing!

Please use in the Altitude Config the Display that is currently used for QNH
If you got 5 Diggits also in the QNH Display then use them. If only 4 diggits there then use this 4 Diggits. In that case a Alt over 10.000ft simply show not the last diggit but thats no matter for our test.
Also go in the QNH Config.... Und use There for testing the Display you currently use for Altitude. Here you can use 4 Diggits or you use 5 Diggits if you want.
If 5 diggits used then a QNH of 1013 is show as 10130 ( also no matter for our Testing)

NOW Do your flights. Try to reproduce the situation.

If the Altitude Display ( That is the origianl QNH Output at the moment ) again stop working you have a issue in your configs and the problem is software based.
If now the QNH Display stop working ( The same Display like before used for ALT) then we can get sure your MaxTube is broke or wrong solder.

OK thank you, but i have to break the whole altimeter is mounted on the panel.
I already thought about it, I did not want to do it.
Today I ordered eBAY new display, with green light, we will see.
Peter

OK thank you, but i have to break the whole altimeter is mounted on the panel.
I already thought about it, I did not want to do it.

Why ?

You should simply change the device....No change on the hardware is needed for this testing !

Display Feet :
DIn 51, CS 49, CLK47 , NUM 1
offset 3324, INT, 4Byte
5 digits, USE left Padding 1,0
display QNH :
DIN 22, CS 24,CLK 26 , NUM1
offset 0330, INT,Byte 2, Interpolation 16211- 1013 Hpa
display 4 digits, left padding 1,0

simply use the Display 1 now for QNH and the Display 2 now for Altitude

with this test we simply want to find out if there is a hardware problem or a software issue.

Whatever.... If its a hardware Problem you must rework your Gauge..... But if we see its a software problem we must just check your configs !

Hey, so I counted the display and yesterday I was flying for 2 hours and everything works, so now I do not know what to say ???
I'm going to try it today, there may be a problem in the fact that the display that stopped working, he's just standing now (QNH) if I do not change him, so he does not move.
Peter

Sorry. There is maby a Translation problem.

I don´t understand your last posting.

Please explane again:

1.Do you "change" the 2 Configs for Testing as i said ?

2. Do i understand correct while a 2 Hour Flight there was no issue. and One Day later there was alreade a problem again?

3. Is it correct that issue NOW is on the same "Hardware Display" but that is now showing QNH (cause you chage it as i recommend)

If i understand all correct then thats a 99% indice of a Broke Max Chip or bad solderwork.

Hi,
1. yes changed
2. yes the problem was not
3. It was thought that the display, which showed badly, so there is now QNH (and its data does not change, still, for example, 1013)

See below, thank you for your help