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Two Md3 in the same CAN Bus

Masia Jean-Baptiste 5 years ago in Master modules / MD3 updated by Gustav Widén (System support) 5 years ago 5
Hello
It's possible to have two MD3 in the same CAN Bus ?
Have you a specification for this application ?

Thank
+1
Hello,
which type of CAN-Bus do you mean?
You can have both connected on a single Master-Bus and both connected to the same Generic or J1939-Bus.
I am sure that both connected with one common expansion-Bus will not work. One MD3 has to be the Master for the expansion module.
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Under review
When you have two MD3:s in your project files, there are a couple of different ways the MD3:s can be connected.
For the multi-master system to work, the MD3:s must be connected using the Diagnostics bus. This will allow you to show values on both display pages from both applications, and measure groups, adjust groups and logs can be accessed on both displays.
To have more than one MD3 in the system, they must have unique addresses, you will need to use an IdTag on one of them to set it to a non-zero address. E.g. address 3.




To exchange real-time data between the applications, an easy way is to connect the "Master" bus, this will allow you to use the APPOUT/APPIN channels to send values between the two applications. What you will need to think of if you want to use the APPOUT is that it consumes a lot of bandwith, the APPOUT protocol was originally designed to allow MC3:s to communicate in a safe way, therefore this protocol has got a lot of overhead. If you have more than a handful of channels to send, I don't recommend this method. 
Note that channels that you only need to show on display pages don't need to go on the Master bus, these are automatically transferred on the Diagnostics bus.
One way to reduce the bus load on the diagnostics bus would be to put the Master(APPOUT) bus on a different CAN bus than the Diagnostics bus. 


The most efficient method is to use J1939 messages that you define yourself for any channel data that needs to be shared between the applications. You then add one J1939 module to represent messages coming from each MD3. The Source address you set (e.g. SA 40 = J1939 cab display) on the MD3, will also be set on the J1939 module in the system layout.

You can of coure add other non-IQAN J1939 modules to this bus also, just as you would normally do, and both MD3:s will be able to access the data from these


As Arno also points out, IQAN expansion modules added to a bus shared by two MD3:s is a special case.
You can have expansions on a bus shared between master modules, but only one of the master modules will own and be able to access the expansion module.
Dear Mr. Widen
I am working on a project that deals with a pressure flow control for my senior design for the Chainless bike challenge by Parker. I have a question and I was hoping you can provide me with an answer for it. can I use Iqan MD3 and Iqan Mc2 on the same bus, known that I have no other supporting modules in the system? and if this possible how do I assign the source address for both. I am using ( iqancreativestudio_with_manual_ed3-15-3 ) platform, I am trying to control my circuit with Iqan MC2 and have the Iqan MD3 as a master monitor unit. Thanks.
If the IQAN-MD3 is not involved in any calculations for the application, and is only used to show values from the MC2 in on the display pages and in the measure groups, tune adjustable values and view the log, then it is enough to just connect the IQAN-MD3 and IQAN-MC2 on the Diagnostics bus, like this: 

You don't need to set any J1939 source address on the modules. The only thing you need to do for addressing is to make sure that exactly one of the IQAN master modules is has IQAN address 0. (note this is not the J1939 source address)

On the IQAN-MD3 display pages, all channels from the IQAN-MC2 automatically becomes available, like this: