Question on EHSI power
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Hi, 2 questions.
1/ regarding power up & “no data” view.
Based on MLU M3 documentation the following situations can occur:
a) blank screen: EHSI is not powered, OR when internal failure
b) NO DATA when: EHSI is powered + MMC not communicating or off
c) EHSI workingNow I’m trying to pinpoint these parameters in shared memory.
- According to -1 the (E)HSI is powered with emergency bus nr2. So am I correct to believe the BusPowerEmergency should be the one to look at?
- Internal failure: as far as I know, not modeled in BMS
- MMC off: I cannot find this in sharedmem, correct?
- I do find a flag for HSI_OFF. What is this flagging. The power to HSI? Or the INS OFF position?
I’m not 100% sure but I think it’s more correct to say that the following is a correct mapping of M3 documentation and available sharedmem flags?
BusPowerEmergency = OFF: blank screen;
BusPowerEmergency = ON + HSI_OFF : NO DATA;
BusPowerEmergeny = ON + HSI is not OFF: EHSI working.Looking at BMS behavior, I can never trigger a “no data” screen, not modelled? If it is, how can I trigger it? Or what flags need to be on/off in sharedmem?
2/ Is the following issue correct behavior or a bug?
Note; I know it’s not correct startup procedure, was justing testing to see if I could trigger a “no data” in various situations and the one below I tried to.a) cold jet
b) set INS to align
c) set MMC ON
d) start the jet
-> EHSI comes alive
e) turn INS to NAV
-> EHSI dead
f) turn INS to OFF
g) turn INS back to ALIGN & later to NAV
-> EHSI comes back.Why would EHSI go off when INS goes from ALGN to NAV?
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I see the no data at ramp with the shared mem EHSI
but power distribution in BMS is not always like the real docs. There are still lots of room for improvement in there
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@Red:
I see the no data at ramp with the shared mem EHSI
but power distribution in BMS is not always like the real docs. There are still lots of room for improvement in there
With Lightnings MFDE I indeed so NO DATA at a certain point. That’s what got me thinking about when I should & shouldn’t appear, and then I noticed I couldn’t get it in BMS (or I’m not testing right).
Can anyone enlighten me on what HSI_OFF exactly flags in sharedmem? And if my logic is correct on the 3 situations mapped to BMS sharedmem?
The 2nd question I also can’t immediately explain, but I’m far from an avionics specialist so wonder what the reason can be.