Clarity on software roles

[snoopy6129]

I've been doing research on cockpit building for over a year now. But I am not sure on the roles of the software interfaces.

My plan is to build a 737NG with P3D, PMDG 737NGX, with Opencockpit hardware (EFIS, MCP, OverHead, MIP, etc). That being said, I know SIOC and FSUIPC (registered version) is involved in translating inputs from the Opencockpit hardware for the flight sim. In my mind, I see these as various layers in the communication pathway (as outlined below):

Layer 1 - Opencockpit Modules - with buttons, switches, LEDs
Layer 2 - SIOC - translates physical inputs from layer #1 to digital signals
Layer 3 - FSUIPC - takes digital signals from SIOC and passes it to the flight sim by converting them to a corresponding keyboard command shortcut (such as CTRL+G for landing gear)
Layer 4 - P3D/PMDG "monitors" FSUIPC for keyboard commands and executes them

Is my understand of the interaction of the hardware and software components correct?

Also, if my understand is correct, how would ProSim 737 fit in? It seems to be a popular item for many builders. Is this a required component? Or is it simply an "add-on" that offers an instructor station and some non-critical enhancements?

Thanks in advance for any feedback.

[Avro748]

Prosim is a complete systems package for the 737.The difference between it and PMDG is that it runs externally from the sim and can run on multiple computers to minimize the impact on performance. If you're already using PMDG, you don't have to use Prosim, but it's up to you.

In terms of the "layers," here's my explanation.

FSUIPC takes thousands of FS variables and constantly writes them to/reads them from so called "offsets." SIOC is a scripting language that lets you select an offset and choose what you want the card to do with it (E.G. if offset 036C (the stall warning offset) is active, activate output 3). Writeable offsets, like switches and buttons, are used in reverse (E.G. if input 2 is active, set 07BC (Autopilot Master) to 1 (on)). Though your idea of it being used as a keyboard command used to be the case, FSUIPC has evolved to allow you to directly control the variable instead, which is useful for non-default commands.

If your using PMDG, this process can be made slightly easier by using OCP4NGX. It's a payware program that is kind of like Lekseecon/PSXseecon except for the 737NGX.

I chose my aircraft partially because it is much easier to interface with the sim than a lot of the other options.

[Roarkr]

If you are using PMDG B737 already, you will not be able to find any better flight model than it has, no need for ProSim IMHO.

By using OC4BA v3 you can simulate all cockpit feature of the PMDG B737 in an easy way. It fits OpenCockpit hardware modules
and is the link between the OC hardware and the PMDG B737 software.

It is Plug & Play, cheap compare to other software, and will let you expand your Cockpit over time and let you fly whatever OC hardware modules you have installed.

[snoopy6129]

Avro7468, thanks for elaborating on FSUIPC. For the offsets, my reading tells me that various switches, LEDS, knobs, etc are pre-defined with a specific offset number by PMDG. If so, can I assume that a reference sheet for these offsets number is available with my purchase of PMD737NGX? Sounds like as long I know how to program in SIOC and also know what the offset numbers are, I have what I need to write scripts for Opencockpit modules. Is this a fair statement?

I will certainly read more on OCP4NGX - sounds like a big time saver for a fairly prices program.

Thanks for your response.

[snoopy6129]

Roarkr,

Thanks for clarifying the role of ProSim and suggesting OC4BA v3. Speaking of versions, I know Opencockpits has different version of their modules (such as their CDU - they are on v3 now). When possible, I would like to buy used OC hardware. If I end up buying older version of their hardware (such as CDU v1), would OC4BA v3 still work?

Thanks for your suggestion and quick response.

[Roarkr]

Old Opencockpits hardware should work as long as they work with SIOC software. There are users of OC4BA v3 that I know use older versions of MCP, EFIS, CDU. It could be that it is necessary to manually set up the configuration, but that is a minor one time issue.

[Roarkr]

Here is example of SIOC variables that is linked to PMDG SDK variables.

~

[Avro748]

Can I assume that a reference sheet for these offsets number is available with my purchase of PMD737NGX?

The list comes with FSUIPC, so you can even look at it now. I think it's in the documentation folder.

[snoopy6129]

Perfect - I appreciate your insight.

[snoopy6129]

The list comes with FSUIPC, so you can even look at it now. I think it's in the documentation folder.

Thanks Avro748, I will look into it. Much appreciated.