Page | 16 Revision 1.4 15 January
2015
CAN Bus
LabSat 3 is capable of listening to, and recording data from, two separate CAN networks. Dual channel CAN
Bus data recording with LabSat 3 can be achieved in two ways. Depending on the mode selected, the CAN
signal will be either digitized and re-created on a raw bit level or decoded and recorded in a time-stamped
text file. The CAN mode operation is selected under the menu option ‘CAN’ in the SETUP section. When
‘digitized’ mode is selected, the channel is configured in the ‘Digital’ menu.
DIGITIZE mode
The ‘Digitize’
mode records CAN data by listening to the bus and sampling the rising and falling edges of the
raw signal. Timing codes are inserted into the recorded GPS data so that when the file is replayed LabSat re-
creates the digitized CAN signal exactly as it appeared during recording. This mode can therefore be used to
capture data along with bus-errors or data-collisions and is synchronised to the RF signal to within
approximately 60 nanoseconds. One advantage of this mode is that there is no-need to configure CAN baud
rate. During replay, the CAN data can be viewed with a CAN Bus analyser tool such as Vehicle-SPY or
CANAlyzer.
When using the digitize method the CAN data is replayed exactly as recorded, there will be no arbitration
with other systems during replay. Therefore, if the CAN data is replayed into a system which is transmitting
its own CAN data, LabSat will ‘speak’ over the top of the other CAN data. This may cause corruption of
some data frames.
LOG FILE mode
Selecting the ‘LOG FILE’
mode of CAN recording enables data to be recorded in an easy to read text log file
as shown below.
The log file contains a short header detailing the LabSat serial number, time, date CAN Bus baud settings
and GNSS settings. Each line of CAN data recorded contains the following space-delimited information:-
1. CHAN - CAN Channel that the data was received on 1 or 2.
2. TIME - Timestamp to 1ms resolution.
3. ID - Identifier, ‘x’ suffix is shown for extended CAN IDs.
4. DLC - Data length code DLC, this shows the number of data bytes within the CAN frame.
5. DATA - Data section, up to 8 bytes of data as indicated by the DLC.
At the end of the log file there will be a summary of the number of CAN messages received on each channel
during the recording.
Labsat3 SN:00323502
DATE:12/06/2014
TIME:13:07
CAN1: 500.00K
CAN2: 500.00K
GNSS: GPS, GLO
CHAN, TIME, ID, DLC, DATA
2 0.060 360 8 0B 70 C8 35 44 60 80 A3
1 0.060 420 8 7B 46 02 84 01 00 3E 1D
2 0.062 620 8 0D 24 02 1B 81 7E 37 02
1 0.063 428 7 00 8E 00 00 37 00 20
2 0.064 200 7 01 F5 01 E2 02 00 00
