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Author Topic: Virtual AGC  (Read 166381 times)
movieman
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« on: August 10, 2005, 08:28:35 PM »

Ok, it's time to:

Update source.
Update Config directory.
Update Scenarios directory.

Build source.

Load 'AS-506 Apollo 11 Yaagc Launch.scn' Happy.

It doesn't do a lot at the moment: the IMU isn't talking to it properly. But it's now wired in and can be enabled by adding:

AGC_BEGIN
  YAAGC 1
AGC_END

To any of the scenario files (I recommend deleting any other AGC saved data in the file when switching between C++ AGC and Virtual AGC). It does save all essential state to the scenario, and it seems that it will happily continue running when reloading the scenario afterwards.

Code is in for Saturn V, Saturn 1b and LEM (running the Luminary binary). Now it's integrated I may have to let someone else do the debugging to get it working as well as the Virtual Apollo did Happy

I've also updated the screenshot on my web site: you can tell it's the Virtual AGC as the 'Prog' entry is blank.

http://mysite.wanadoo-members.co.uk/marui/orbiter_agc.jpg

As usual, let me know what I've broken Happy.

P.S. I presume there's no problem with us having the Virtual AGC code in CVS? It's a lot easier than having to download it from elsewhere, and I've had to make a couple of changes anyway.
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movieman
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« Reply #1 on: August 10, 2005, 08:43:50 PM »

One other thing: we need to get the 'COMP ACTY' light working on the DSKY now, since the Virtual AGC will light it up when running Happy.
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Tschachim
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« Reply #2 on: August 11, 2005, 06:19:03 AM »

Hey movieman, that's great!  Very Happy  Very Happy  Very Happy

Building was fine, I took only a very quick look (still busy with the LM regarding VESSEL2 and these instabilities), I think there are a fews odds and ends to fix (V35 lamp test for example), but a lot of work is done!
I can help getting the Virtual Apollo stuff working again in a few days (too busy at the moment), if you like (and it's necessary then, you are really fast!)

Ahh, and yaAGC and the GPL is no problem, Ron gave us the "Orbiter special permission" already a few months ago!

Many thanks and cheers
Tschachim
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movieman
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« Reply #3 on: August 11, 2005, 06:43:49 AM »

I'm not going to have much time for the next few days myself. I'm pretty sure it must be something to do with the I/O channel simulation as the IMU is tracking acceleration but the AGC doesn't think it's running.

It does use the 'special' channels which are inverted in the real AGC, so there could be bugs in that code. I found and fixed a couple and checked in the fixes, but that still don't make it work.
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movieman
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« Reply #4 on: August 11, 2005, 05:10:46 PM »

Double post.
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movieman
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« Reply #5 on: August 11, 2005, 05:11:05 PM »

Ok, I fixed the main problem with the VERB 35 lights, I created a function to set them but forgot to call it Happy. I still don't really know how the STBY and RESTART lights are lit on the real AGC.

The biggest issue now is probably getting the IMU working properly: I don't know what I've changed that would have broken it. I get 211 and 1601 alarms.
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movieman
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« Reply #6 on: August 11, 2005, 06:54:15 PM »

I also fixed the 1107 alarm when the AGC starts up: we need to force it to do a 'hard reset' by setting the AGCWarning flag.
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movieman
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« Reply #7 on: August 12, 2005, 09:00:11 AM »

Since the version of Virtual AGC we're running is a few months old and has some bugs, I think I'll try tonight to split out the few functions we've changed and then update to the latest version.

Hopefully then future updates will just be a matter of putting a few #if 0 lines in the code for functions we've replaced and dropping it in.
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movieman
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« Reply #8 on: August 12, 2005, 12:52:56 PM »

Ok, the IMU is now up and running Happy.
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movieman
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« Reply #9 on: August 12, 2005, 01:38:57 PM »

And the AGC now works all the way to orbit, though the numbers it displays are a little off from the correct values.
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movieman
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« Reply #10 on: August 12, 2005, 02:32:22 PM »

Now updated to the latest version of Virtual AGC. The numbers displayed look closer to the correct values, but still aren't quite right.
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movieman
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« Reply #11 on: August 12, 2005, 07:12:31 PM »

We now start up with the IMU caged. So to begin a flight with the Virtual AGC you first need to click down the 'IMU Cage' switch to turn it on, and then the AGC will see the data come through. If you leave it caged, you'll get whacky values on the DSKY during launch and errors and 'NO ATT' lights.

I'm not sure quite how we're meant to turn the IMU on and off, so for the moment this seemed like an easy solution.

BTW, there's no Prog 15 (TLI burn program) in Colossus 249. I wonder if that was a new program added for the version used on Apollo 15? At the moment we'll have no way to fly to the Moon with this version of the software, other than to hand-fly the SIVB.
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x15
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« Reply #12 on: August 13, 2005, 01:34:18 PM »

ok I just did my first powerup of the LEM yaAGC computer

I'm still getting the 1107 program alarm on startup

what did you do exactly to get rid of it in the CSM, movieman

thanks
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Tschachim
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« Reply #13 on: August 13, 2005, 02:00:58 PM »

Hi movieman,

as I already assumed you were really fast integrating all this stuff! It's really fantastic! Happy Happy

Quote from: movieman
Now updated to the latest version of Virtual AGC. The numbers displayed look closer to the correct values, but still aren't quite right.

I'm very curious, what are the AGC and Orbiter values for apoapsis altitude and periapsis altitude in earth orbit (V82)?

Quote from: movieman
I'm not sure quite how we're meant to turn the IMU on and off, so for the moment this seemed like an easy solution.

With the G/N IMU PWR switch located on Panel 100, but since there's no panel 100 at the moment this is a good solution IMHO!

Quote from: movieman
BTW, there's no Prog 15 (TLI burn program) in Colossus 249.

That's strange, Ron means it was used by Apollo 8 and 9, and Apollo 8 did a TLI burn?

Cheers
Tschachim
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Tschachim
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« Reply #14 on: August 13, 2005, 02:30:59 PM »

You are right about TLI:

"... the TLI maneuver is controlled by the IU (Instrument Unit) on the launch vehicle, and not the computer in the CM" (from here: http://history.nasa.gov/ap08fj/02earth_orbit_tli.htm)

... Ron is working on Artemis 072 aka Colossus 3 (Apollo 15-17), but this will take some time...

Cheers
Tschachim
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