Problem with ICAW display

[IADS_user]

I am trying to create an ICAW display for the Flight Controls engineer
during our telemetry flights. This ICAW page will display the 1553
bus statuses and warnings that appear during a flight. However, I am
running into a problem. I populated the ICAW definitions table as
suggested in the IADS manual. When the ICAW display is
running during a TM session, it displays dozens upon dozens of
incorrect warnings during the whole flight test. I am uncertain to
why these messages appear. Per the Flight Controls engineer, these
messages are incorrect and should not appear during a flight. During
a normal flight, only a few messages should appear from time to time.
It does not matter what we set the Bit Numbering Convention to in the
ICAW data properties tab. The same result occurs. My company's data
acquisition system outputs values in IEEE floating point format, but I
was told that does not matter in IADS. Do I need to create derived
parameters within IADS to run this display properly?

A company that is partnered with us on the same program is using the
same ICAW display page but without any issues. Our ICAW display page
is setup the same as theirs but they utilize a different data
acquisition system.

Can anyone suggest anything that I may have missed or overlooked?

Many thanks in advance.

[Watzlavick, Robert L]

We get lots of false ICAWs during dropouts - could that be causing the problem? Or are you seeing the incorrect messages during periods of good TM?

-Bob

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[James Bretz]

Hello,

> A company that is partnered with us on the same program is using the
> same ICAW display page but without any issues. Our ICAW display page
> is setup the same as theirs but they utilize a different data
> acquisition system.
>
> Can anyone suggest anything that I may have missed or overlooked?

One guess is that your system is hooked up to telemetry data and is thus
receiving bad data when the ground system loses connection with aircraft.
This occurs from time to time when the aircraft goes behind an obstruction,
maneuvers in a way in which the transmitting antenna isn't optimally
aligned, etc. Anyway, when the data system loses connection with the
aircraft, it almost always throws a "spike" (large random value) into the
data stream for the parameter. This is a grand issue repeated time and time
again with PCM systems... A very poor design in my opinion.

On board an aircraft, these problems are rare to non existent (but still
possible). So, is one system on board the aircraft and the other on the
ground? This might explain the differences. If this isn't the case, then
please describe the two systems.

We do actually have some techniques available to help combat these problems.
What version of Iads are you using?

Jim

[James Bretz]

> We get lots of false ICAWs during dropouts - could that be causing the
> problem?
> Or are you seeing the incorrect messages during periods of good TM?

Yep, my thought exactly.....

I think I know what the difference is here. This is a customer that built
their own hand crafted data system and custom connection interface. In the
custom data system, they eliminate all the bad data before it's sent to
Iads.... but it sounds like they are now hooking up to secondary system
consisting of a traditional Lumistar decom card (or other).

Does this sound familiar ZAAlie?
Jim