级别定义再ISO 14229-7 中
1.Diagnostic class I
Smart and simple devices like intelligent sensors and actuators requiring none or very low amount of
diagnostic functionality. Actuator control, sensor reading, and fault memory handling is done by the
master node, using signal carrying frames. Therefore, specific diagnostic support for these tasks is not
required. Fault indication is always signal-based.
2.Diagnostic class II
A diagnostic class II slave node is similar to a diagnostic class I slave node, but it provides node
identification support. The extended node identification is normally required by vehicle manufacturers.
Testers or master nodes use ISO 14229-1 diagnostic services to request the extended node identification
information. Actuator control, sensor reading, and fault memory handling is done by the master node,
using signal carrying frames. Therefore, specific diagnostic support for these tasks is not required. Fault
indication is always signal-based.
3.Diagnostic class III
Diagnostic class III slave nodes are devices with enhanced application functions typically performing
their own local information processing (e.g. function controllers, local sensor/actuator loops). The slave
nodes execute tasks beyond the basic sensor/actuator functionality and, therefore, require extended
diagnostic support. Direct actuator control and raw sensor data are often not exchanged with the master
node and, therefore, not included in signal carrying frames. ISO 14229-1 diagnostic services for I/O
control, sensor value reading, and parameter configuration (beyond node configuration) are required.
Diagnostic class III slave nodes have internal fault memory, along with associated reading and clearing
services. Optionally, reprogramming (flash/NVRAM reprogramming) of the slave node is possible. This
requires an implementation of a boot loader and necessary diagnostic services to unlock the device
initiate downloads and transfer data, etc.
The primary difference between diagnostic class II and diagnostic class III is the distribution of
diagnostic capabilities between the LIN master node and the LIN slave node for diagnostic class II while
for a diagnostic class III LIN slave node, no diagnostic application features of the LIN slave node are
implemented in the LIN master node.