High bus loads can cause many issues with delayed frames or lower priority messages being completely
dropped out. This can be caused by a combination of slow bus speeds, multiple devices on the bus, short transmit intervals and unnecessary bus traffic.
On the EC-C series inverters the bus speed can be selected in the system parameter group. Note that changing CAN bus addresses or speeds requires a re-boot of the device to apply the changes.
If raising the bus speed cannot be done, or it already is as high as possible, the bus load can be reduced by removing unnecessary messages sent by the inverters, or lengthening the transmit intervals on either end.
By default, the inverters send all status messages as shown in the relevant communication manuals. If some of them are not necessary for the chosen application, they can be disabled by writing zero (0) to the transmit time period parameter of the relevant message.
Parameter group J1939:
3020.20n4 TxMsgn_period
If the bus load is unknown, it can be calculated, but there are also cheap USB-CAN adapters that will show the load, such as the Peak System PCAN-USB FD. It is noteworthy that a bus load of 60-70% is already considered high if there is no proper network management.