Help needed

[tdog]

Hi all,

I'm using a NI USB 6009 DAQ to measure voltages and currents accquired from a set of 108 nodes. The nodes are divided into clusters of 18 nodes each. I have analog signals from the 6 clusters feeding into the DAQ. I have also placed DAQ Assistant in my LabView code and generated a task consisting of 7 channels. The channels are Cluster 1 Current, Cluster 2 Current, ........ Cluster 6 Current, Node Voltage.

Basically, I want to sequentially measure the node voltage of each of the 108 nodes, identifying each node by a binary address made up of 5 bits and a latch. I also want to measure the current through each cluster.

All of the hardware and digital circuitry has been penned out but I'm not sure what the LabView code shouldbe like. I can get the 6 cluster currents over the 6 current channels. But how do I get the individual node voltages for all 108 nodes coming in over the one channel and group the voltages into the 6 clusters that they belong to.

Can someone help? It will be appreciated.

Cheers.

[tbob]

Not sure I understand your question.  You want to take 108 voltage readings and separate them into 6 clusters?  Do your clusters have place holders for the voltages?  That would be needed to add the voltages to the clusters.  That would be 18 votages per cluster.  How does each voltage relate to the 6 clusters?

I'm guessing here.  You would need to have your 108 voltages in an array.  Feed the array into a For Loop with indexing enabled.  Use case statements to determine which loop iteration you are on.  Case 0..17, add the indexed voltage to Cluster 1.  Case 18..35, use Cluster 2.  and so on.

[tdog]

It may have seemed unclear because I used the word 'Cluster'. Sorry about that.

By Cluster I did not mean a cluster function in LabView, but simply a group of nodes. That is, I have 6 groups of 18 nodes each. I do have place holders to store the 108 node voltages, and each node is identified by a binary number of 5 bits and a latch (I guess, this could be used to relate the node voltages to the clusters/groups).

What I really can't understand is if I pass all 108 voltages over the same channel, how do I sample the accquired signal to measure all 108 node voltages sequentially in a continuous fashion. That is, I get the voltage for the 1st node, then the 2nd node, and so on up to the 108th node, then measure the node voltages again.

Cheers.

[tbob]

Now its even more unclear.  What do you mean by a latch?  How and why are the nodes grouped?  What consists of a group?  Are you just calling the first 18 nodes a group?  Are they physically tied together in some way?  Are they in a container or in a tab?  Or are they just individual channels on a DAQ measuring device.

How are you reading the voltages?  DAQ channels, DAQ task, DMM?  What is the structure of your node?  You say each node is identified by a 5-bit number.  What holds the number and how does it connect to a voltage reading?  If you get sequential readings, does the readings come out as an array from a DAQ function?

I think you need to start from the top and tell us exactly how you have structured your system.