Best method/practice to run two loops (read + write) simultaneously in sync

Hello,
I thought I had a program working that could write and read simultaeously with reasonable accuracy, but have discovered it may not be as reliable as I thought (it sometimes gets out of sync/jumps steps).
Is there a good guide, tutorial or recommended method to do this reliably, in sync and efficiently?
Should I use notifiers? and/or timed loops?
I have a write loop, which sends steps to some type of equipment (stepper motor or magnet etc) at no more than about 100 Hz.
I have a read loop, which reads data from a detector (eg photodiode, the signal being dependent on the write step), at no more than about 1000 Hz (the read loop runs faster than the write loop)
I then pass information from one loop to the other (one loop writes to a group, the other reads from it).
I then save data to a file by saving the contents of the graph.
Thanks
Solved!
Go to Solution.

Jeff_Tech wrote:
(1) .... in sync....
(2) ... (the read loop runs faster than the write loop) ...
Aren't these two statements a contradiction?
There is significant information that you have left out, for example is it sufficient for the two to be in sync or is it also necessary that they occur at a very regular rate.
In what way do the two depend on each other? Is this a control application where the output depends on the input in some way or is it simply a excitation/response pair.
Are you doing software timed single point acquisition?
Does it need to run for extended periods of time or it it just a finite sweep each time?
In any case, the right thing do probably do is run both hardware timed from the same clock. Setup the output array for the AO and arm the AI, then start both running from the same clock (e.g. you could tie the AI conversion to the AO clock). Read the buffered AI data at leasure in a loop that does not need any special timing.
Can you show us some code so we get a better feeling what you are doing?
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