Kent,
Here's the latest: I have set the source for the Master Timebase to "/Dev1/20MHzTimebase" using the property node DAQmx Timing>>More>>Master Timebase>>Source. I did this for all the tasks on devices 3, 4, and 5. I then left the "Source" pin unwired for all the "DAQmx Timing (Sample Clock)" blocks and specified the different rates for the different tasks.
With this configuration, everything runs with no errors. I think I'm definitely on the right track.
However, I'm trying to determine if there's a way I can be certain of the synchronization. Here's what I have been using:
Let's say I have a 2 second test. I command the Analog Output task to 5V from 1s to 1.4s, 0V otherwise. I have this output connected to both the analog input and digital input. I should see the analog input and digital input change at the same intstant in time, right? I'm seeing the digital input change states from 0 to 1
before the analog input reports any change. Is this expected?
Also, I have an external volt box (set to 5v) that I switch on and off during the 2 second test. This signal is connected to both the analog and digital inputs. When looking at the data from these channels, I see the same behavior with the digital line changing state before the analog line begins to move from 0V. The difference is anywhere from 1ms to 2.5 ms. It seems as though the amount of time difference between the analog and digital increases over the course of test. I understood this to be clock drift from the two boards, but now that should be eliminated, right?
I'm sure this is confusing. Please let me know your thoughts, especially if there is a better way to establish confidence in the synchronization.
Many thanks,
Kevin