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Old 08-25-2009, 11:03 AM   #1
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Default What is the Engine value and what does it mean

Okay, in looking over some logs from this weekends event, I see a value in megalogview labeled Engine:1 anyone know what that is and what it means?

My values range from 0 to 133 so surely they mean something, I just wondered what.
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Old 08-25-2009, 11:37 AM   #2
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That field is an 8 bit word that carries information about the current state that the engine is in. The decoded decimal numbers are misleading, you have to visualize it as raw binary data for it to make sense. Each bit in the word indicates the state of a given function, where 1 means that function is true, and 0 means that function is false.

At the bottom-right of the log screen, you'll see this field:



The "engine" datablock is what carries the information that populates that display. When the LSB (least significant bit) is 1, that means that the engine is in the "Run" state. When the sixth bit it true, the engine is in the "Decel" state. Since bit #1 (LSB) has a value of 1 when decoded to decimal, and bit #6 has a value of 32, when the engine is running and also in decel, you'll see a decimal value of 33 for engine state.

(I'm using one-based numbering here for the sake of the non-CS majors. Technically, the first bit (LSB) is bit #0, and the last bit (MSB) is bit #7. But MLV calls them 1-8, so I'll maintain that here)

Last edited by Joe Perez; 08-25-2009 at 12:00 PM. Reason: schpelling and clarification
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Old 08-25-2009, 11:42 AM   #3
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The bit functions are as follows:
(bit position, decimal value, function)
Bit 1, value 1, "Run"
Bit 2, value 2, "Crank"
Bit 3, value 4, "ASE"
Bit 4, value 8, "Warmup"
Bit 5, value 16, "TPS Accel"
Bit 6, value 32, "Decel"
Bit 7, value 64, "MAP Accel"
Bit 8, value 128, "Idle"

Last edited by Joe Perez; 08-25-2009 at 11:59 AM. Reason: added bit 7 from examination of msns-extra.h file
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Old 08-25-2009, 11:46 AM   #4
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So for us dummies, we can look at the picture you linked and not worry about the "engine" value

You never cease to amaze me Joe. Please tell me you at least had to look that up somewhere.
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Old 08-25-2009, 11:58 AM   #5
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Quote:
Originally Posted by Chris Swearingen View Post
So for us dummies, we can look at the picture you linked and not worry about the "engine" value

You never cease to amaze me Joe. Please tell me you at least had to look that up somewhere.
Yeah, you can just look at the picture.

I figured out the functions of bits 1-6 and 8 by looking through a log and determining which functions or sets of functions corresponded to which decimal engine values. For bit 7, I had to look at the source code, which also provided some clarification of bit 5. (Turns out I should have looked at the source code first, as that whole block is pretty obvious once you find it.)
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