PM MCP offsets for "STD" button / QNH

[Induced_Drag]

Dear All,

When I use the PM software MCP all is well. Pushing the "STD" button selects and displays "STD" on the PFD. Now rotating the baro knob (still using the PM software MCP panel) changes the QNH which is displayed in smaller white font below the "STD" caption on the PFD - this is all correct.

What I want to do is now interface my Opencockpit EFIS and MCP hardware to do the same. I've been looking for an offset to trigger "STD" with and I'm guessing but PM MCP must have a location to store the "white QNH" value below "STD" which will replace the "STD" caption when the "STD" button is pressed again (now returning to a specific QNH).

Has anyone any advice / working code to help me. I've tried offset &5414 bit 18 for the "STD" button but it doesn't seem to do anything on my setup!

Regards,
ID.

[PeterH]

Hi ID,

I believe in your msg there´s a typo because according to the offset table of PM the offset for setting the QNH neg. / pos values is x5418 Bits 18 resp. 19.

May that´s the problem.

Peter

[PeterH]

Hi, me again,

just checked my setup. I´ve realized the STD / local QNH select via FSUIPC and found the offset x6202.
Pse check with FSUIPC offsets on the button page. THis will most probably solve your problem.

Hope this helped.

Best regards

Peter

[Induced_Drag]

Hi Peter,

Thanks for your time and the information.

I will utilise your info and report back.

Regards,
ID

[Induced_Drag]

Hi Peter,

I've been looking at the problem again but no solution as yet.
Instead of using x5414 bit (I thought this may work originally) to trigger the change in PM from QNH to "STD" I've found a way to do this re PM Kcodes and the throughpass offset.

I still can't set / find the PM local QNH, offset x6202 you mentioned does not seem to be used on my setup, its value stays at 0. I will continue to investigate. Any further comments much appreciated.

Regards,
ID.

[Peter Dowson]

I still can't set / find the PM local QNH, offset x6202 you mentioned does not seem to be used on my setup, its value stays at 0. I will continue to investigate. Any further comments much appreciated.

There are three QNH values stored in local PM offsets, and all are listed in their document:

552E = current Copilot QNH (set and in use), in 16 x hPa.
5536 = Pilot stored QNH (the subscale) when STD set
5538 = Copilot stored QNH (ditto),
but note that both of the latter are in 100 x ins Hg (for some unfathomable reason).

The pilot QNH set and in use is the standard FS one at 0330, and you can tell whether the STD mode is set or not by

5528 bit 3 = 1 means Pilot in STD mode
5528 bit 14 = 1 means Copilot in STD mode.

Not sure why you couldn't find these in the PM Offsets list on their site, as that's where I got them from.

Regards

Pete

[Induced_Drag]

Hi Pete,

Thanks again re your info. I have been looking at this earlier today.

Firstly, I previously mentioned using x5414 bit 18/19 to set "STD", having looked at this again, this is for the Airbus not Boeing - my mistake.

I also found the offsets you mention BUT there is an odd result which I will attempt to explain. Firstly, I've found Kcode 049 successfully switches "STD" on / off.

If I use the offset x5418 to inc/dec the 'white QNH' (Capt's background QNH) it does partially work. The Capt 'white offset' seems to be stored in x5536 (found offset docs - as you also state).

x5536 stores the 'white QNH' in inches of Hg (x100) - as you say why! Although the QNH is displayed in mb, when x5418 is used to increment the 'white QNH' it just adds 1 (i.e. 0.01 in Hg) instead of 1 mb. Thus it needs 2 or 3 increments / decrements to change the QNH by 1 mb!

If I alter the 'white QNH" directly via x5536, it does store my value BUT interestingly when "STD" is pressed it reverts back to the QNH that was stored in x5536 before I wrote to this address. I therefore conclude the MCP s/w must be using some other internal locations I cannot access.

I can solve my problem if Kcodes exist for inc / dec the QNH. I can't see any but I don't fully understand it all as the offset doc goes on to talk about M, V etc.

Do you know of another way to inc / dec the QNH with a Kcode or something similar ?

Thanks again Pete,

Regards,
ID.

[Peter Dowson]

If I alter the 'white QNH" directly via x5536, it does store my value BUT interestingly when "STD" is pressed it reverts back to the QNH that was stored in x5536 before I wrote to this address.
Is this with the latest PM MCP program? I thought Enrico had corrected all of the direct writing capabilities -- it was part of a package of changes needed to may it usable from an "Its Your Plane" copilot.


I therefore conclude the MCP s/w must be using some other internal locations I cannot access.Hmm. Strange. If it still happens with the latest versions, please write to PM support and ask about it.


Do you know of another way to inc / dec the QNH with a Kcode or something similar ?I only know of what is listed in their document.

Regards

Pete

[Induced_Drag]

Hi Pete,

I've emailed Jonathan at PM and he will forward it to Enrico to comment upon.

I am running the latest versions of GC and MCP (just checked PM website), thus I await there comments and will post again when I have more information.

Regards,
ID.

P.S. Thanks for FSUIPC.

[kni-dk]

Hi ID and Enrico (if U a listning)

Did you get any hints you could use or any results with your investigation?

I tried ½ a yr ago and got vthe answer it was in the documentation, but I have now used properly more than 30 - 40 hrs. testing several different setups and offsets combination - with absolutely no usefull results. More I have hardwired my MCP so all my encoders are directly connected to FSUICP (via BUx0836) (earlier it was through an old FSBUS solution - old but was working inclusive speed dial, which I have lost in the hardwiring, every time I ask for support I got the answer from PM support that they did not support FSBUS - so I decided to follow the (bad) advise - beside a slower and more difficult use of all the dials (SPD/HDG etc) I got nothing.

1) I can confirm the same story as you about the x5536 offset !

2) I am using the lastest MCP/CDU/PM systems sw

I have a suggestion for Enrico, which I believe would help most of us:
I am NOT a software engineer, so excuse me if I am udsing the wrong word or expressions - I am sure U understand the idea.
Make a new (2 actually one for CAPT and one for FO) offsets, this new offset will alter the QNH (inc(dec) in normal mode (feeding the x0330 and FO xFFFF) and when STD set it will alter the "temp QNH" (and of course write the white digits), when push the STD again the "temp QNH is written to the x0330 adress)

[Induced_Drag]

Hi kni-dk,

I have been discussing this with Jonathan at PM, they are currently very busy but will hopefully look at it soon.

If you buy the CP Flight MCP and EFIS control panel the "white" QNH works fine due to the code being correct within the CP Flight software BUT at present the storage of the "white" QNH does not seem to be saved in an offset we the general simmer can access.

I'm hoping this will change soon and I will post the solution when solved. I use Opencockpit hardware so that I can program it myself and I feel it is resonably priced. I've had a play with the CP Flight hardware, excellent stuff, but I cannot justify spending that much.

Regards,
ID.