04-18-2012 08:21 PM
Anyone can help me out of the problem for no reply from ECM using J1939 Transport Protocal Reference Example?
I am currently using MEFI4B ECM, cRIO9023, X.Net 1.4.0, NI9862 and Labview 2011.
The ECM is powered up by DC 12 Volt power supply and only connect with NI 9862 through CAN H and CAN L. Since I want to collect the history information from ECM, I have not connected the ECM with an engine. All the other PINs except CAN H, CAN L and power are empty.
The problems I am now encoutering:
After I run the example, I can receive the broadcast from ECM (they are current engine status such as):
However, when I request ECM to send the specific information to NI 9862, nothing can I receive:
For example, I send
Request (NI 9862 Source Address 03)
ID: 0x18EAFF03 (Request Message)
Data Field: 177 254 0 255 255 255 255 255 (First 3 byte, ECM historical information PGN)
I expect to receive the incoming message ID: 0x1CEEB100 and the relevant data field. However, I cannot receive this ID.
1. For my understanding, I send the request message to ECM, the ECM should broadcast its information on the CANBus. Why can't I receive this broadcast message? I try other type messages, also no expected reply received by NI 9862
2. I set the device source address as 3 by keying in the value on the setup. After I run the program, will the address (03) be claimed by NI 9862?
Thanks for your concerned!