Since the inception of IQANdesign 5.01, it is possible to measure (with IQAN run or IQANdesign ) bus utilization and device status inside the System Layout view. These measurements are performed from the perspective of the master selected during measure mode.
Some users have observed that in a multi-master system, where some of the IQAN masters maybe sharing communication with the same J1939 device(s), the J1939 device status may be reporting an “OK“ status if one of the IQAN masters is selected during measurement and in other instances, the same J1939 device may be reporting a status “Unknown” when a different master is selected during measure mode.
This behavior has to do with the selected master having CAN communication functions setup in that module’s application logic. In the System Layout example shown below, we have two IQAN MD4-7 master displays connected to a common engine ECU. Only the master display called Engine room display has J1939 communication functionality ( i.e JFINs, JPINs, JFOUTs, JPOTs channels) setup in master’s application logic to communicate with the engine ECU ( MTU engine). On the other hand, the other master display called Main bridge display has no such CAN communication functionality defined in its application logic.
The image below shows the IQAN master display with CAN communication functionality in its application logic. Since the master is selected during measure mode, the J1939 device (i.e MTU engine) reports “OK” for status:
Conversely, the picture below shows the IQAN master display selected has no CAN communication functionality in its application logic. In this case the engine ECM the master is connected to will report status “Unknown” when the system layout is in measure mode.