Connecting the SPEEDBOX20 to DL1 or DL2
The SPEEDBOX20 uses Race Technology’s GPS engine. This is optimised specifically for automotive applications and produces more accurate and more rapidly updated speed measurements than can be achieved by the commercial GPS receiver that is used in the DL1 or the 5Hz DL2. As such, the SPEEDBOX20 can usefully be connected to the DL1 or DL2 to provide an upgrade to the quality and rate of the GPS data that they sample.
In order to connect the SPEEDBOX20 to the DL1 or DL2 you need to do the following:
• Configure the DL1 or DL2 to accept RT format serial data over its serial port.
• Disable the DL1 or DL2’s own internal channels for GPS position, acceleration, GPS speed etc. If you have two sources of the same data, then you will get unpredictable results.
• Connect the SPEEDBOX20 to the logger using a null modem cable that is connected between the DL1/DL2 and the RS232 output on the SPEEDBOX20 wiring loom. It is also necessary to connect a GPS antenna to the DL1/DL2 (not shown) since the SPEEDBOX20 does not currently supply the date and time over RS232. The DL1/DL2 must therefore get this from the GPS signal.
"WARNING": To avoid any possible damage to the car paintwork, please take care when mounting magnetic GPS antennas. In particular make sure that there are no dust or grit under the antenna. In some cases it maybe required to add additional protection to the paintwork prior to mounting the antenna to avoid damage.
Figure 6: Arrangement for connecting a SPEEDBOX20 to a DL1 datalogger