Landing rates

[Goshob]

Hi,

I have a question about using FSUIPC5 with P3D V4. It is concerning how and in which variable the landing rate can be read? I know at least 2 tools, one of which is Smartcars, which are reading the landing rates and using for their purposes. LRM is another tool for reading the landing rates. Mandatory requirement for both is the FSUIPC to be loaded in the SIM.

Thank you in advance!

 

[John Dowson]

Hi,

you probably want offset 030C - from the offset status document: Vertical speed, copy of offset 02C8 whilst airborne, not updated whilst the “on ground” flag (0366) is set. Can be used to check hardness of touchdown (but watch out for bounces which may change this).

There is a discussion on landing rate calculation here: https://www.avsim.com/forums/topic/524247-how-is-landing-rate-calculated/

Cheers,

John

[Goshob]

Hi John,

Thank you for the reply. I had been through the post you mentioned. Thank you! It is exactly offset 030C, which I am interested in. It would be appreciated if you would like to share more details how it can be read or where I can find more explanation about it.

Thank you!

[John Dowson]

That depends on what you want to do! You could, for example, read/monitor it in a lua script, in a C/C++ program, or use the logging facilities provided by FSUIPC to display the value in the log file, main window or title bar.

[Goshob]

Hello Pete,

Let me try to explain the reason for all my queries till now and ask an additional question.

I am flying with a VA using Aerosoft Airbus 320 pro. I noticed that since starting using this new AC, the landing rates registered by SmartCars had increased with app. 200 fpm. This unfortunately is a negative point in my performance, which I wanted to clarify. 

It was found that TFDi Design, who are providing SmartCars to the VA is monitoring the value of offset 030C, which FSUIPC provides. At the same time Aerosoft were very kind to explain that they are using the original P3D v4 variable “A:Vertical speed, feet per minute” in the PFD display of the Aerosoft Airbus Professional.

My question is why between the values got from “030C” (I believe via SimConnect) and the original P3D v4 variable “A:Vertical speed, feet per minute” there is a constant difference of app. 200 fpm? In other words for a certain landing at touchdown, offset 030C displays 560 fpm when at the same time the PFD states app. 370 fpm.

Would appreciate your comments. 

Regards, Georgi

Edited November 6, 2018 by Goshob

[Pete Dowson]

3 hours ago, Goshob said:

It was found that TFDi Design, who are providing SmartCars to the VA is monitoring the value of offset 030C, which FSUIPC provides. At the same time Aerosoft were very kind to explain that they are using the original P3D v4 variable “A:Vertical speed, feet per minute” in the PFD display of the Aerosoft Airbus Professional.

My question is why between the values got from “030C” (I believe via SimConnect) and the original P3D v4 variable “A:Vertical speed, feet per minute” there is a constant difference of app. 200 fpm? In other words for a certain landing at touchdown, offset 030C displays 560 fpm when at the same time the PFD states app. 370 fpm.

As described in the Offsets list, all FSUIPC is doing, in order to populate offset 030C, is make a copy of offset 02C8 continously whilst in the air, at the same time as it is updated, and stopping doing this the moment "on ground" is  signalled. Both pieces of information come from SimConnect at the moment they change. 030C is updated at the same time as 0328 excpt on ground, so it cannot always have a constant difference from that vertical speed value. 

02C8 is the value of SimConnect variable "VERTICAL SPEED".  The "on ground" indicator, which is at offset 0366, is the SimConnect variable "SIM ON GROUND". Just use the FSUIPC monitor (right-hand side of the Logging tab) to log these and check for yourself.

I've no idea what SmartCars" is, but unless it is an internal DLL or Gauge then it is going to be nowhere near as precise at recording this as FSUIPC.

Pete

 

[Goshob]

Hi Pete,

Thank you for the comments! In regards to the above, let me share my observations also, putting aside SmartCars or whatever other third party software.

I had requested an experiment and visualized the debug of P3D and FSUIPC logging for offset 030C. Vertical speed, which comes from the SIM is all the time having a constant difference of  app. 200 fpm compared to the one, which comes from 030C (the values of 030C are higher than those of the SIM). Moreover, the PFD of the bus is showing the one, which comes from the SIM.

There is something, which comes into my mind after reading your reply stating that offset 030C, is making a copy of offset 02C8 continuously whilst in the air. Please correct me, if I am wrong, but the format of 02C8 is 256*mps. Right? Is there a chance for some wrong conversion to fpm (feet per minute) which the format of 030C is?

Thank you!

 

[Pete Dowson]

18 minutes ago, Goshob said:

Please correct me, if I am wrong, but the format of 02C8 is 256*mps. Right? Is there a chance for some wrong conversion to fpm (feet per minute) which the format of 030C is?

As the documentation states (please do refer to it), 030C is a COPY of 02C8. They are therefore bound to be both the same units, and the copy is made as soon as 02C8 is changed by SimConnect, whilst in the air!

Didn't you bother to do the logging I suggested? It will show the raw VERTICAL SPEED value received from SimConnect as well as the values in the two offsets. Log entries like this:

   305013 Monitor IPC:02C8 (S32) = 669
   305013 Monitor IPC:030C (S32) = 669
   305013 SimRead: 02C8="VERTICAL SPEED" [also 0842] [also 030C]
            FLT64: 2.61257028694

That last value IS the value received directrly from SimConnect, and is therefore the Sim value at that time.

2.61257 x 256 = 668.8 = 669 to nearest integer (the offsets are 32-bit signed integers, "S32" in the monitor).

Pete

 

[Goshob]

Dear Pete,

What I wrote above was my lunch break thoughts. I do bother and will do the logging tonight when I go home. I am UTC+4.

Have a nice day!

[Hanse_Rolf]

Pete, 

thanks for the explanation. As I am together with Goshob try to solve our problem I did the logging as suggested and the result is as follows:

1139297 Monitor IPC:030C (S32) = -879
1139297 Monitor IPC:02C8 (S32) = -879
1139297 SimRead: 02C8="VERTICAL SPEED" [also 0842] [also 030C]

But the point is that using the Aerosoft Airbus Professional we get different values as stated above (please see the screenshot attached). As you can see from it the P3D v4 direct read variable value for vertical speed "A:Vertical speed, feet per minute” from the P3D v4 SDK as well as the value displayed on the PFD are app. 200 feet lower. Do you have any explanation for this difference? 

Thanks and have a nice day…..

Rolf

 

[Pete Dowson]

3 hours ago, Hanse_Rolf said:

As you can see from it the P3D v4 direct read variable value for vertical speed "A:Vertical speed, feet per minute” from the P3D v4 SDK as well as the value displayed on the PFD are app. 200 feet lower. Do you have any explanation for this difference? 

Soorry, what P3D v4 SDK variable which is not a SimConnect variable? How are you obtaining it -- what code? The value I log for VERTICAL SPEED is the SimConnect supplied variable -- see the SDK yourself, "simulation variables" in the SimConnect API section.

[LATER]

See my later post which explains your confusion!

Pete

 

[Hanse_Rolf]

Pete,

thanks for your quick and in depth answer.  I am a member of the Aerosoft Airbus Professional development team and responsible for a part in which the landing rate is an important feature. That is the reason why I got involved. We use an internal DEBUG tool to access / monitor certain variables (internals as well as from P3D v4 SDK) which I used to check GOSHOB's remark on too high landing rates of the Aerosoft Airbus. But I will ask the responsible developer of our team (he is back from vacation beginning of next week) about this issue…. If we could clarify the issue I will let you know.

Rolf

[Pete Dowson]

3 hours ago, Hanse_Rolf said:

1139297 Monitor IPC:030C (S32) = -879
1139297 Monitor IPC:02C8 (S32) = -879
1139297 SimRead: 02C8="VERTICAL SPEED" [also 0842] [also 030C]

But the point is that using the Aerosoft Airbus Professional we get different values as stated above (please see the screenshot attached). As you can see from it the P3D v4 direct read variable value for vertical speed "A:Vertical speed, feet per minute” from the P3D v4 SDK as well as the value displayed on the PFD are app. 200 feet lower

Going back to this.  You are talking about feet per minute,. -879 is 256 x 3.4336 metres per second.

3.4336 mentres = 11.265 feet,

11.265 feet per second = 675.9 feet per minute., which agrees with the display in the picture you showed.

So, there is no difference! Please do be aware of the units being used. Goshob himself did recognise that the offset values were 256 x mps.

Pete

 

[Pete Dowson]

15 minutes ago, Hanse_Rolf said:

If we could clarify the issue I will let you know.

Thank you. But after looking again at your previous posting, I think you are just confused about the units. (as, I hope, I clarified in my post previous to this).

Pete

 

[Hanse_Rolf]

Pete,

thanks for the quick clarification. Indeed I was talking about feet / min because this is the normal "unit" used to state "landing rates" and "vertical speed". As I am not familiar with the FSUIPC is there also a way to get  030C or 02C8 in feet/min? Thanks,

Rolf

[Pete Dowson]

1 minute ago, Hanse_Rolf said:

As I am not familiar with the FSUIPC is there also a way to get  030C or 02C8 in feet/min?

The reason for the apparently odd units in many FSUIPC offsets is that those were the units actually found in the locations equivalent to the offsets but in the FS98 module called "GLOBALS.DLL". Since the prime purpose of FSUIPC through all the versions of FS from and including FS98 (released late 1997) has been compatibility, the units in those equivalent offsets are the same as the older original units. Newer added offsets can use later appropriate units, but forcing older programs to be revised has always been avoided as a main FSUIPC policy.

To convert the 256*m/s units into fpm, simply multiply by ((60*3.28084)/256).  If you are not writing a program to interface to FSUIPC to do this, then use a Lua plug-in, which can of course then display the results in real time.

Pete

 

[Hanse_Rolf]

Thanks for the clarification and your help. Now we have to clarify if "SmartCars" is also using this offset and if it really "recalculates" it into feet/min. 

Regards,

Rolf

[Pete Dowson]

10 minutes ago, Hanse_Rolf said:

Now we have to clarify if "SmartCars" is also using this offset and if it really "recalculates" it into feet/min. 

Wasn't that the display shown in the picture you posted earlier? If so, as I computed for you, it has the vertical speed correct.

Unless Smartcars is using FSUIPC to get its data, then it cannot be using that offset. The offsets are part of FSUIPC now -- only in FS98 were they in the Sim. The work involved in developing successive versions of FSUIPC was in tracking down the locations of the values needed in each new FS version. That changed in FSX when SimConnect was invented, with my involvement, to make it all easier and hopefully version independent.

Pete

 

[Hanse_Rolf]

1 hour ago, Pete Dowson said:

Wasn't that the display shown in the picture you posted earlier? If so, as I computed for you, it has the vertical speed correct.

No, that was a internal Aerosoft development tool we use for debugging. As already explained this value in fpm comes directly from the sim, without recalculation and is as you confirmed correct. "SmartCars" also logs the landing rate and states that is also in fpm. As the result differs and the software also requires the use of a registered version of the FSUIPC we thought TDFI also uses the offset value 030C. As now is confirmed that all of our values are correct and identical the problem seems to be in the "SmartCars" program. 

Regards, and have a nice evening.

Rolf

[Pete Dowson]

7 minutes ago, Hanse_Rolf said:

As now is confirmed that all of our values are correct and identical the problem seems to be in the "SmartCars" program. 

Okay. Thanks for letting me know.

Pete

 

[Goshob]

Good afternoon Gentlemen,

Seems you had gone too much ahead during my absence.

However and in order to make the things clear, I would like to say some sentences also. 

Mr. Hanse_Rolf and I made some experiments using one and the same plane landing on different airports at different weather conditions. I had asked the program team of SmartCars also for feedback about variables used in their software. TFDi Design confirmed that they are using FSUIPC offset 030C for recording the landing rate. Moreover the conversion calculation for transferring m/s into fpm is applied in SmartCars, which was confirmed by our experimental flights.

Stating all the above, the things for me got cleared at this stage. It would be highly appreciated if Mr. Rolf has to say something more because he actually was the active part in the discussion when I was away on my business related duties.

Thank you for the support!