Download - Little, Big Racing

R&S Business Unit Automotive
4.1 – Memory / Shark
Via L.Romagnoli, 24 - 41033 Concordia sulla Secchia (Modena) Italy
Tel.: +39 0535 57711 (r.a.) - Fax.: +39 0535 54550
Uffici amministrativi: Via G. Brodolini, 35 - Fax.: +39 0535 54533
Email : guest@digitek.it - Internet : http://w w w .digitek.it
DATAVIEW Pg. 33/133
The Shark data logger has 2 totally independent memory locations which are written to simultaneously. The Local
Disk (internal flash) is either 128Mb or 256Mb, depending on logger specification. The removable flash card memory
may be any size as long as it is larger the Auto Lap limit which is typically 40Mb.
Lap storage
The data is divided within the logger as separate files; the file division is normally created when a lap beacon signal
is seen. With this method the user is able to download individual laps rather than removing all of the laps stored in
memory. A download of multiple laps only creates a single file on your PC.
Latest data - on/off
From table Manager the user is able to decide which type of memory management is used.
Latest data on – When the logger memory becomes full the oldest lap file is deleted from memory as an entire block
Latest data off - When the logger memory becomes full the memory storage stops, new data can only be stored if
the Clear data command is used. See section 5.1
Auto lap Limit
This is an internally imposed maximum size for any one internal lap file, when the limit of 40Mb (typical Shark
setting) is reached a new lap file is automatically created. This Auto lap Limit is needed for data security, systems
which do not use a lap timing beacon may fill up the memory without ever seeing a lap beacon signal, the latest data
function would then automatically remove the oldest lap file, which in this scenario would be all of the data. The
40Mb Auto lap limit avoids this possible problem.
Notes about Auto lap limit
The internal channels Time and Space are not incremented by Auto lap limit
The LAP counter is not incremented by Auto lap limit
The ABS lap counter does increment at the Auto lap limit
The LAPTIM message records the time from logger on to the previous Auto lap limit
Auto lap limit is applied to Local disk as well as flash card memory.
The size of the auto lap limit is a compromise between ensuring that the Auto lap limit does not interfere with the
normal lap beacon > lap beacon events and possible data loss resulting from use without a beacon.
The maximum data throughput of the Shark at 64,000 bytes per second (typical value) means that at maximum
acquisition rate the 40Mb (40,000,000 bytes) / 64,000 = 10minutes (approx) between each Auto lap limit. This would
never normally conflict with a race car lap.
Memory storage
Starting from a logger with empty flash card and empty Local disk, the data is stored to both locations
simultaneously. At the point of memory being full, the earliest lap file is deleted from both the Local disk and Flash
card.
If a blank or partially filled memory card is inserted into a logger with stored data in Local disk memory the 2 storage
locations become out of synchronisation. This is not a problem and they both then work independently of each other,
this situation also occurs when a flash card of larger memory size is used.
The Shark logger does not need the Flash card in order to function. If no card is inserted, the logger can be
downloaded in the normal Ethernet method using the Local disk only.
When using the Flash card to transfer data, the Local disk memory is mostly redundant and only used as a back up
source in case of Flash card failure.
data view_std_manual v1.4.doc Digitek Spa Digitek Spa