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Project Apollo Beta 7.0 released!
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Author Topic: LM Switch functions  (Read 738 times)
Hlynkacg
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« on: September 14, 2012, 12:24:11 AM »

So i've been going through my LEM's VC and adding actual effects to each switch. Panels 1 and 2 are in the bag but I've run into some confusion on panel 3, specifically on the stability control section.

There are three mode control switches, Pitch, Roll, and Yaw.

These switches have three positions OFF, PULSE, and DIR (direct), I know how pulse and direct settings worked but I'm a little shady on off. Did putting the mode cotrol switch in off disable ALL inputs along that axis? or only stability control.

On a similar line what about the 4 RCS quad enable/disable switches also on panel 3? how did these differ in functionality from the RCS quad enable/disable switches on panel 2? did they?

My primary refernce has been the LM famailiarization manual and the apollo news resource. While these docs have more than enough information for me to get a good ways int subsystem modeling they tend to be a little vauge when it comes to the actual button pushing.
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eddievhfan1984
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« Reply #1 on: September 14, 2012, 10:20:20 AM »

Try this link:

http://www.hq.nasa.gov/alsj/alsj-LMdocs.html

I'm already reading up on the control subsystems, which includes panel 1, 2, and 3 diagrams.

According to what I'm reading, the so called OFF mode in the panel 3 linear switches is actually supposed to engage a MODE CONTrol switch for the stabilization system—there's a three-position rotary switch to select between stabilization OFF, ATT HOLD (PGNS/AGS will damp rotation rates/hold attitude when the pilot does not send a rotation command), and AUTO (full control of rotation, ullage jets, and rate stabilization by the PGNS/AGS). Think of it like the CMC mode switch in the CSM: OFF(LM)=FREE(CSM), ATT HOLD=HOLD, and AUTO=AUTO. Happy Actually, even PULSE mode enables PGNS/AGS processing of AEA (RHC in the CSM) commands.

The panel 2 RCS on/off switches, from NASA's LEM GNC flowcharts I've read, tell the LGC which RCS jet pairs (not the whole quad) are in use for PGNS operation. The panel 3 controls appear to set the heater mode for the RCS quads, whether they should automatically engage, allow manual turn-on, or just be off. Tongue

Confused yet? LOL
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Hlynkacg
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« Reply #2 on: September 14, 2012, 12:26:25 PM »

To make sure I've got this correct

There are essentially three modes for each axis, a pure manual mode (Direct), pulse mode, and an Automaic mode (MODE CONT) and the automatic mode's behavior is determined by the  position  of the attitude hold switch.

I can work that.

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eddievhfan1984
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« Reply #3 on: September 14, 2012, 01:00:11 PM »

Yeah, but even PULSE falls under computer control. It's just that in that mode, you're only limited to one thruster pulse at a time, and if the computer is running a program, the pilot still won't be ale to make inputs. You'd either have to turn the rotary switch to OFF or the toggle switches to DIRect.

Does your LEM have the ability to use the vAGC?
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Hlynkacg
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« Reply #4 on: September 14, 2012, 03:11:33 PM »

Quote
Yeah, but even PULSE falls under computer control. It's just that in that mode, you're only limited to one thruster pulse at a time, and if the computer is running a program, the pilot still won't be ale to make inputs. You'd either have to turn the rotary switch to OFF or the toggle switches to DIRect.

Got it  Thumbs Up

Quote
Does your LEM have the ability to use the vAGC?

No, but I'm interested in changing that.

I just haven't dug deep enough into the code to figure out how to go about doing it.

Right now MY AGC consists of only a simple routine that accounts for CG shifts and mimics the functionality of the default autopilots using the y+ Axis (axis of thrust) instead of the z+ (Orbiter default).
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eddievhfan1984
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« Reply #5 on: September 14, 2012, 10:07:35 PM »

Oh, I also forgot, direct mode doesn't disengage PGNS either—it just means you can fight the computer with more thrust.

As far as the AGC, talk to some of the admins here—they should be able to help you integrate the LEM's software.
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Hlynkacg
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« Reply #6 on: September 19, 2012, 01:15:05 PM »

Got it up and running, thanks Thumbs Up

Now my priorities are modeling cabin atmosphere temp, press, and composition so I cankeep my UMMU's alive.
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