how to do DAQmx synchronization with multiple devices

[Jshen6]

Hi,

Here I attached the new code in .llb named 
"des_v2_Multi_Function_Dev_Synch_AI_AO.vi". The old code I used to run one of the device is named "des_v2_Multi_Function_Synch_AI_AO.vi", which is also included in the .llb. In the new code, I included a 
master card's output and input, as well as two slaves cards inputs. But it 
couldn't run, could you help me to check it please?

Thanks a  lot.
Sincerely,
Jie

[DollaBrillz]

Hi,

What error messages are you getting? I would recommend running Highlight Execution on your code to see exactly where theses errors pop up. I can see from looking at your code that you start the AI and AO Voltage Task twice on the Master Device: Once to read the samples, and again to write to a file. This will cause errors as a task cannot be started when it is already in the "running" state. I also noticed that you are running a For Loop around your entire code to dictate the number of times the code iterates. A better way to implement this functionality would be to put a read/write VI and the Write to Measurement File in the Loop, so that the tasks do not have to be reconfigured and restarted on every iteration. The current configuration will cause performance issues.

[Jshen6]

Hi,

I really appreciate your advice, but I am not sure how to modify those errors you mentioned.

There are several broken run errors. But when I try to link the wires to the place I thought it was right. The wire disappear automatically. I don't know what's wrong with that. The broken errors are in the first box. 

I used an example as a reference in multi-device synchronization called "Multi-Device Synch-Anolog Input-Finite Acq-Ext Dig Start. vi". Since it is the first time I program in Labview, so I just tried to mix the example program and the previous program I was using together.

I attached the example program I was using. Could you tell me more specific which part of the example I should use and which part I need to change?

Thanks a lot.

Sincerely,

Jie

[DollaBrillz]

Can you send me a screenshot of the location in your code where you are running into the Broken Run Arrows? It is not clear from the Library you sent where you are running into this problem.

Thanks!

[Jshen6]

Hi,

Here is the screenshot and I circled the broken wires. I also attached the .vi that I wrote. It is called "des_v2_Multi_Function_Dev_Synch AI-AO.vi" in the library.

Thanks a lot.

Sincerely,

Jie

[Jshen6]

Hi,

I changed the modified code a little bit. The newer version is called "des1_v2_Multi_Function_Dev_Synch AI-AO.vi" in the .llb file. There are still some broken wires that I dont know how to fix them. Could you help me please?

Thanks a lot.

Sincerely,

Jie

[DollaBrillz]

There are open terminals on the bottom portion of the case structure because the reference and data wires are not connected in every case of the case structure. It also appears that you had multiple terminals on the Error output of the case structure. I would suggest deleting these terminals and rewiring. I was also able to reconcile the broken run arrow by deleting and rewiring the synchronization type wire to the case selector terminal of the case structure.

I hope this helps!

[Jshen6]

Thanks a lot guys! Problem solved. I use a RTSI cable to connect three cards. I also followed the example in Figure 10 in the following website to modify my code:

http://www.ni.com/white-paper/4322/en/#toc9

Thanks again.

Sincerely,

Jie

[gangmu1]

Could you explain DAQ mx synchronization with multiple devices not in Labview but in C# codes.