I haven't looked at the PLX serial data system, but it might be like the Techedge units. The following is Techedge specific.....
The serial data stream is broken up into specific "segments" called "frames". Each frame has a defines setup, to enable the data held within it to be decoded correctly. The Frame is also a set number of "bits" long. The frame has the following attributes...
- Start bits ( indicates a frame beginning)
- Frame sequence ( the frame count number )
- Timer data ( just an indicator of elapsed time for reference )
- User Data ( or actual logged data )
- Frame CRC ( to ensure the frame was received correctly )
The user data contains the Lambda / AFR data in digital format, but it can also contain many other logged parameters, RPM, VSS, A/D data etc. However, the V2 is currently only configured to understand the Lambda / AFR data in the frame. To do this, the V2 probably understands the frame header ( start and sequence ), the Lambda / AFR data and possibly the CRC. This means that there is a large portion of the frame that the V2 does not understand or care about, this is where your "boost" data would normally reside. A good indicator that the V2 is only configured for the Lambda / AFR data is that they are the only PID's you can select in the V2.
Having said all that, why can't you just log MAP via the std PIDs?
Simon.