Measurement Computing DBK70 - Manual (Page 74)

6-8 Fundamentals of Obtaining Vehicle Data 928494 DBK70 User’s Manual
For this PID, the response data begins on bit 48 and the length of the data is 2 bytes, so the Index should be
set to 48 and the Length should be set to 16. In cases were the bits are embedded in a larger block of data,
the Index should be set to point to the 1
st of the desired bits.
In cases where the network module can be directed to continually send the desired message, the DBK70
can be programmed to send the request message just one time. This will minimize the amount of network
traffic. To send the request message in the DBK70 Message field just one time, set the Update Rate field
to –1. The request message will be sent when the DBK70 is powered on or whenever the Timeout value is
exceeded.
Using Diagnostic Data Packet
Diagnostic Data Packets (DDP), as defined in SAE J2190, allow more than one data value from a network
node to be encapsulated into a single, user-defined, message packet. Due to the compactness of the
transmission, DDP messages can provide diagnostic data over the network at a faster rate than by
conventional means.
The following information will assist you in using DDP on the DBK70. Consult the J2190 document for
a complete explanation of DDP and its usage.
Using DDP requires 3 basic steps; defining a data packet, requesting the data packet, and receiving and
parsing the data packet. The defining and requesting steps are required only one time. After these steps are
executed, the defined data packet is constantly broadcast on the network, allowing the diagnostic tool to
receive the data packets as they are being broadcast.