Doing parallel measurements

[m-s]

The title is a bit of a misnomer since Labview accesses each VI in some random sequential fashion. However, in my measurement, I am trying to measure three quantities. Two of these measurements take differing, but somewhat long times (longer than the third).

I use error out / error in to sequence the operations. What I was hoping to do was to use the error out cluster from the excitation VI to initiate all three instruments in parallel and then at the end, wait for all three error out clusters from those three VIs to become available before proceeding.

I can easily make a dummy VI that takes in three error clusters and then generates an output cluster (internally connected to just one of course - I have no idea how to merge contents of the three error clusters). Of course, under normal operation, neither of them supposed to contain anything.

The question is - is this a wise strategy ? Or is there something better (that you could suggest in response) ? 

[F._Schubert · Accepted solution]

There is a Merge Error VI that you can use.

The only problem I faced using this: If I have a dependency of my instruments the order of errors for the Merge Errors vi is of importance. If a parameter of Instr2 is used as an input parameter of Instr1 and there is an error on the wire of Instr2, a wrong value might be passed to Instr1 generating an error on the error wire of Instr1. The Merge error VI will display me the error on wire1 and discard the error message from Instr2. So in this case I put the wire from instr2 to the error in 1 and the error wire from Instr1 to the error in 2.

Felix 

[m-s]

No, there is no interdependency in the measurements. These measurements are truly independent of each other (three different physical quantities, and three different instruments).

Merge Errors.vi - thanks.

Message Edited by m-s on 03-26-2010 12:20 AM

Message Edited by m-s on 03-26-2010 12:25 AM