National Instruments CAN 372139B-01 - Manual (Page 251)

Chapter 6 Automotive Diagnostic Command Set API for C
© National Instruments Corporation 6-87 Automotive Diagnostic Command Set User Manual
ndUDSReadDataByIdentifier
Purpose
Executes the UDS ReadDataByIdentifier service. Reads an ECU data record.
Format
long ndUDSReadDataByIdentifier(
TD1 *diagRef,
unsigned short ID,
unsigned char dataOut[],
long *len,
LVBoolean *success);
Input
diagRef
Specifies the diagnostic session handle, obtained from ndOpenDiagnostic and passed
to subsequent diagnostic functions. Normally, it is not necessary to manually manipulate
the elements of this struct.
ID
Defines the identifier of the data to be read. The values are application specific.
Output
dataOut
Returns the ECU data record. If you know the record data description, use
ndConvertToPhys to interpret this record.
len
On input, len must contain the dataOut array length. On return, it contains the number
of valid data bytes in the dataOut array.
success
Indicates successful receipt of a positive response message for this diagnostic service.
Return Value
The return value indicates the function call status as a signed 32-bit integer. Zero means the
function executed successfully. A negative value specifies an error, which means the function
did not perform the expected behavior. A positive value specifies a warning, which means the
function performed as expected, but a condition arose that may require attention.
Use the ndStatusToString function to obtain a descriptive string for the return value.