Innovate Motorsports LogWorks 3 - Manual (Page 13)

LogWorks3_Manual_1.01.doc - 13 -
2.1.3 Logging resolution
Logging most channels involves interpreting voltages. Typically for most of today’s sensors the
voltage range is 0-5V. When a data logger reads these voltages they are converted into a number
that is represented digitally. Converting the voltage to that number is the task of an analog-to-
digital converter (abbreviated A/D or ADC). The highest number a A/D can represent conforms to
the max. Voltage it can read and also determines the finest resolution it can read. The number of
‘bits’ of the ADC specifies that highest number. For example for an 8 bit A/D the highest number
is 255 (2 to the power of 8 minus 1). It could resolve the input voltage into 5/256 Volts. For a 10
bit A/D the highest number is 1023 and the resolution is 5/1024 Volts. So the resolution for any
sensor is:
Range / ( 2 to the power of [number_of_bits] ) or Range / 2^N,
Where N is the number of bits of the ADC.
Most MTS devices that read external voltages or internal sensors use 10 bit resolution A/D’s. The
exception is the AFR/Lambda data.
Even though the Lambda range goes from 0.5 to infinite, it is limited for logging purposes to 0.5 to
1.523 Lambda.
This is a 10 bit range with a resolution of 0.001 Lambda.
The LMA-3 internally digitizes with a 16 bit ADC. It then uses the extra resolution to filter out
noise and finally reduce the resulting resolution to 10 bit for the MTS data stream.
LogWorks always stores all channel data in the 10 bit raw format as digitized. How
the numbers are interpreted for the user display depends on the user settable channel
configuration. But the raw stored 10 bit numbers will not get changed when the
interpretation changes.