J1939 TSC1 and update rate error

Lorenzo Simonetti 6 months ago in IQANdesign updated by Gustav Widén (System support) 6 months ago 1 1 duplicate

Good morning,
I kindly ask for help regarding the following problem:
as soon as I start the engine, the system detects an "Abnormal update rate" error SPN639 FMI 9 and a warning SPN1235, FMI9. I want to clarify that after a while that the engine works, the RPM + and RPM- command does not work anymore until I switch it off and on again. All engine data are correctly displayed and managed. Can you help me please?

Best regards,
Lorenzo Simonetti

Duplicates 1

A guess is that maybe you are sending the TSC1 command at a too slow repetition rate for the engine controller. 

If you are using the built-in TSC1 channel, its default is to send every cycle, and default cycle time is 50 ms. For speed override most engine controllers require a faster repetition rate. Check the documentation on the engine controller. 

In IQANdesign, you can have run the TSC1 channel faster than your cycle time, it can be as fast as 10 ms. 

If you are already on 10 ms and still have problems, the issue could be that total bus utilization is too high, so messages do not get through to the engine controller on time due to other messages on the bus.