Combustion Flag Offsets

[English Rebel]

I have a light on my electrical panel that indicates a connection between the left and right hand busses (it's a horizontal bar).   This is the correct sequence.

When neither engine is running the light should be OFF signifying that the two busses are not connected (the emergency battery connects the two).  When the right engine starts the buss connection should close and the light should come ON.  When the left engine starts  the buss connection should open and the light should go OFF.

To try and achieve this I used offsets 0894 and 092C (combustion flags for the left and right engines).  I used the Value On/Off setting for the right engine I set a value of 1 for On and a value of 0 for Off (so when the engine is off the light is OFF and when the engine is running the light is ON).  For the left engine I used Set value On with a value of 0 to turn off the light OFF when the engine is running?

For some reason this doesn't see to work correctly.  It's okay for the engines start up sequence as the light comes ON when the right engine starts and goes out when the left engine starts.  However when I shut down the left engine the light comes ON (as it should) but when the right engine shuts down the light stays ON.

I checked that the combustion flags where working okay by logging the reads. Anyone figure out where I went wrong?
Thanks

Alan

[mgh]

Can you post the code you're using?

EDIT

There are 4 possible cased for the state of the two engines. Are you handling all four?

[English Rebel]

I'm only using the Combustion Flag.  

Code is

Right Engine

Offset 0894,

Data Type: Byte,

Action: Value On/Off

Value On: 1

Value Off: 0

 

Left Engine

Offset 092C,

Data Type: Byte

Action: Value On

Value On: 0

 

Thanks

Alan

[mgh]

I'm missing something but what code is that?

 

As I said there are 4 cases to handle:

 

Left off/right off

Left off/right on

Left on/right off

Left on/right on

[English Rebel]

Sorry to be obtuse but I'm not sure what you are telling me.  I'm not using any code I'm just using the offset and its state.  I'm doing all my entries in Flight Deck Solutions InterfaceIT as all my switches are connected to their interface card.  What I posted in #3 is what options I have in that program.  Also those offsets are read only and 0 is Engine OFF and 1 is Engine ON.

Thanks

Alan

[Graham Pollitt]

Those 2 offsets are not 8 bit numbers they are non negative 16 bit numbers (integer) are per the documentation.

 

Using byte as the variable type would only read 8 out of the 16 bits

[English Rebel]

Graham

 In InterfaceIT the options I have are:

1. Byte
2. Float16
3. LongInt
4. LongWord
5. ShortInt
6. SmallInt
7. Word

The documentation I have says that the combustion flag offsets are U16 (unsigned word ?) but I'm not sure if I should use Word or LongWord.

Thanks

Alan

[Pete Dowson]

 In InterfaceIT the options I have are:

1. Byte
2. Float16
3. LongInt
4. LongWord
5. ShortInt
6. SmallInt
7. Word

 

Those are non-standard terms. See if they are defined on "interfaceIT" documentation. The 16 bit unsigned one might be Word or ShortInt or SmallInt. It isn't possible to guess between these.

 

As mgh said, there are 4 conditions, and you want the light to be lit as follows:

 

Left off/right off -> light off

Left off/right on -> light on

Left on/right off -> light on

Left on/right on -> light off

 

In other words, you want the light on when the two offsets are different, and off when the two offsets are the same.

 

Now how you "program" that using the facilities you have I have no idea. You would need to consult the InterfaceIT documentation again.

 

Pete

[English Rebel]

Pete

There is nothing in their manual so I sent them an email. 

Thanks

Alan