FSUIPC 4.20 autopilot problems

[fanda]

Hello Pete

I can now definitely confirm that FSUIPC 4.20 causes the trouble in the Dash-8 autopilot operation, and 4.15 not.

Will it be possible to get a version 4.16 for testing, to see which version is the first one, affected by this problem ?

Thank you very much

regards,

Oleksiy Frolov

Majestic Software

[Pete Dowson]

I can now definitely confirm that FSUIPC 4.20 causes the trouble in the Dash-8 autopilot operation, and 4.15 not.

Sorry, could you please elaborate? I have no idea what you are talking about at present. Is that aircraft using something in FSUIPC for its autopilot, and if so what? Most of the values provided by FSUIPC are simply pass-through's from SimConnect. It doesn't "cause" anything by itself.

Also, versions 4.2xx use the SP2/Accel version of SimConnect, if installed, whereas 4.1xx used at most the SP1 version. Are you using SP2/Accel or just SP1 with FSX?

And have you tried the latest update, 4.208, from the FSX downloads above?

Will it be possible to get a version 4.16 for testing, to see which version is the first one, affected by this problem ?

Before doing any such testing I'd need to know a lot more. If you are the programmer of the autopilot and wish to discuss this problem in more detail, please write to me at petedowson@btconnect.com.

Regards

Pete

[fanda]

Hello Pete

Thank you for the answer. It seems that the change in the timing due to the new simconnect interface in the latest fsuipc has caused the autopilot to react differently than before. We've simply re-tuned the time constants to compensate, so it works..

>Also, versions 4.2xx use the SP2/Accel version of SimConnect, if installed, whereas 4.1xx used at most the SP1 version. Are >you using SP2/Accel or just SP1 with FSX?

Yes, I do. I have tested both 4.20 and 4.15 with FSX SP2.

Actually the fact that the autopilot was working (far) less stable with the SP2 Simconnect (FSUIPC 4.20) could suggest that the FSX data, in the newer simconnect version is being accessed slower, than before.

With best regards,

Oleksiy Frolov

Majestic Software

[Pete Dowson]

Thank you for the answer. It seems that the change in the timing due to the new simconnect interface in the latest fsuipc

The new SimConnect interface isn't in FSUIPC but in the new SimConnect for SP2/Acceleration. Nothing in the FSUIPC end has changed except that it links to the SimConnect SP2 version if present. With the Windows Side-by-Side library system the library user has to explicitly request the version it needs. Before 4.20 FSUIPC couldn't link to SP2 because it didn't know the correct manifest values.

... has caused the autopilot to react differently than before. We've simply re-tuned the time constants to compensate, so it works..

Strange. I would have thought yor algorithms would have had to work with a variety of timings as FSX performance is so varied on different folks' systems. It will also vary with DX9/DX10 selection, video cards, and so on.

The only difference that I'm aware of between FSUIPC 4.2xx + FSX SP2/Accel and FSUIPC 4.1xx + FSX SP2/Accel is that the former will be using Named Pipes for the transfer of data (which uses shared memory) whilst the latter still uses TCP/IP -- the same as using 4.2xx with FSX+SP1 or before.

The timing differences should merely be that of less latency -- in other words the data should arrive in FSUIPC from FSX after a shorter time than before. It is certainly more efficient -- FSUIPC can ask for a lot more data before it impinges upon FSX performance with SP2.

I have tested both 4.20 and 4.15 with FSX SP2.

Right. So the only difference that I know of is the use of Named Pipes instead of TCP/IP. If you had done the same tests with FSX SP1 you would have seen where the difference was more quickly.

Actually the fact that the autopilot was working (far) less stable with the SP2 Simconnect (FSUIPC 4.20) could suggest that the FSX data, in the newer simconnect version is being accessed slower, than before.

No, sorry, I find that very hard to believe. All my measurements show that SimConnect using named pipes is far far more efficient. I could understand a difference if you found the same on SP2 with both 4.20 and 4.15, because that would indicate a change in FSX itself, probably in the SIM1 engine. Microsoft certainly have made some changes there to support some of the Acceleration facilities

Could you please tell me which variables you are reading in FSUIPC for the autopilot control, those which you have had to make timing adjustments for? I'd like to do some tests on them, just to prove to myself what is happening. If this is confidential information tell me in an email to petedowson@btconnect.com.

Regards

Pete