Single Master Diagnostic Bus

Chris Litwin 10 months ago in IQANdesign updated 10 months ago 2

Does assigning the diagnostic bus to a specific bus do anything in a single master system? I've connected to systems with IQANrun and IQANgo on busses that are not designated diagnostic without any issue. As far as I could tell, they had full functionality within the apps. It seems more like whichever bus you connect to using IQANgo or IQANrun has full diagnostic ability, as long as it is not of a type that can't mix with a diagnostic bus.

Thank you,


That is correct. You can connect using IQANdesign/IQANrun/IQANgo to any 250 kpbs bus, with generic CAN as the exception. 

Essentially any unused bus or bus type that only gives warning and not error when combing bus types in the system layout. 

When using IQANgo, you may have noticed the G11 will be identified with Machine ID if it exists in the system layout and is physically connected to the Diagnostics bus. If the G11 is plugged into a different bus, IQANgo will just show it as a G11. 

If you plug in to a different bus, keep in mind that the bus utilization will become significantly higher when there is both diagnostic CAN traffic and CAN traffic for the modules that are in the application. 

I had not noticed that, good info. Having to define the location for the diagnostics makes it seem like the diagnostic traffic is always there, but obviously that is not the case since it follows wherever you connect to. Side topic, on an MD4 the CAN bus C and D are lower throughput rate than A and D. What percent would you estimate the rate to be compared to the A and B?