Wanted to give others a heads up
Application to control engine RPM with a CAN J1939 TSC1 message using a DP500 or DP700 requires a message rate of 10 ms.
I found that the displays execution time varies between 2ms and 40 ms. The result is unstable engine RPM because the engine will switch over to idle if the TSC1 message is not received in a 10ms period.
In this case a controller is required for this job for a stable execution time below 10ms.