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Answered

J1939 transport protocol transmit rate

Rick Yorke 2 months ago in IQANdesign updated by Gustav Widén (System support) 1 month ago 3

Making use of J1939 > COMPID enabled and J1939 > SOFT enabled on the MC43 with IQAN 6.08.24.8136 . Have encountered an issue where the Transport Protocol Data Transfer (PGN 60160) is occurring at too fast of a rate.

It was observed that the data packets for the COMP ID and SOFT ID messages is being transmitted at a rate of ~540us. The J1939-21 standard indicates a minimum of 50ms between packets.

This fast rate is causing issues with the receiving device, in particular handling the SOFTID as in this case it is 11 packets. The COMPID (5 packets) is being handled for the most part.

Is there a way that the Transport protocol packet rate can be set, or is this truly an issue in the firmware?

+1

If you make a request to the global address 255, the response will be using BAM.

This is paced at 50 ms, as J1939-21 prescribes 50-200 ms for TP.DT in multipacket broadcast.

If you make a request to the address set on the IQAN master, the response will be via RTS/CTS.

The response can be sent back to back, as J1939-21 specifies 0-200 ms for directed multipacket.

+1

Will update to use a global request.

Do see the RTS/CTS messages in our log requesting 4 packets. Seems the PHD70 display is not pausing when sending the CTS and more or less see everything coming at ~540us.

Thank you for the clarification.