hongxiang yu 8 months ago in IQANdesign • updated by Gustav Widén (System support) 8 months ago • 2
Have any way to set maximum bytes for JFOUT multipacket. Such as current default value is byte 42 but i just want to control DLC at byte 32.
Customer support service by UserEcho
Supplenmentary qeustion : Why send the same message and send method are On request that the PGN will be different on CAN trace when select YES or NO in Multipacket
On the CAN trace, you will see the CAN frames used for the J1939 Transport Protocol, PGN 60416 for Connection Management (either broadcast announcement or RTS/CTS), and PGN 60160 for Data Transfer.
The DLC on these frames is always 8, this is the upper limit for classic CAN.
What multipacket does is that it splits it over multiple CAN frames using the J1939-21 transport protocol.
If the IQANdesign JFOUT is configured so the highest index on any parameter is 32 as in your example, there will be five frames with payload data on the Data transfer message (PGN 60160).
32 bytes of data to be sent and 7 bytes of payload data per frame gives 32 /7, rounded up to 5 full frames.