Switch configuration

[himi]

Hi

    I have to connect 16 signal lines to 16 lines on UUT. I have 3 UUTs. Each signal should be able to connect to the corresponding line in the UUT. Effectively this makes it a 16x48 configuraion. I would like to know how can i achieve this in a best possible way so that there are no unused channels on any of the modules.

I thought of using 2503 in 6x1 2 wire quad configuration. However the probelm with this is that a row will connect to 6 channels. In this case 3 channels(columns) are wasted, I need it to connect to only 3 channels.

Do let me know.

Thanks

[Now_With_Underscores]

Hey himi,

Instead of a 16x48 matrix (768 relays), we could go with 16 4x1 muxes (64 relays)... I think you were heading in this direction; if so, I just clarified :).  

NI doesn't offer a 3x1 mux, but the PXI-2576 is an excellent 4x1 mux, which would allow you to test 4 DUTS, or use the last channel on each mux as a test circuit.  The 2576 can supports several topologies; I'd recommend the 2-wire sixteen 4x1 mux topology, which gives you 16 2-wire (differential) 4x1 muxes.  In other words, you'll get 32 4x1 muxes, with 16 controllable pairs.  This twice the density I believe you're looking for, but it is the closest match we offer for your 16 signals routed to 3 DUTs.

Another option would be to use two PXI-2503 modules in the 2-Wire Quad 6x1 Multiplexer Topology, but again this has excess channels and is more expensive than the 2576 option above.

[himi]

Hi

  But i have a question here. If i am correct, i think that a signal connected on a mux line will be switched simultaneously to the four out lines. But i want the signal to be connected to the UUTs individually.Example: I want signal 1 to be connected to UUT1, then disconnect from UUT1, connect to UUT2, disconnect from UUT2, connect to UUT3 and then disconnect from UUT3. I have to do this for all the 16 lines.

Is this possible with a MUX configuration.

Thanks

[Now_With_Underscores]

Hey Himi,

Muxes by default will only connect to one output at a time, creating a connection from the common to a single channel.  For example, when we connect from com0 to ch1, ch0, ch2, and ch3 remain disconnected.

Since the 2576 has 16 of these muxes, and since each mux is mutually exclusive of the others, all we'll need to do is hook up each wire of each DUT to one 4x1 mux, and then tell all the muxes to connect a particular DUT.

[skinnedknuckles]

I took the time to create images showing the configurations (topologies) available for the PXI-2576 (see attachments).  For simplicity, I'll refer to the numbered common connections as inputs and the numbered channel connections as outputs.  I think the easiest way to understand the topologies is to start with the Sixteen 4 x 1 Multiplexer where each of the 16 inputs (COM0-COM15) have 4 outputs each.  Then for the Octal 8 x 1 Multiplexer topology all of the odd numbered inputs delegate their 4 output connections to the numbered input that precedes it (all of the COM1 outputs are delegated to COM0 and so on).  This reduces the available inputs by half but doubles the number of output for each one.  This pattern repeats itself again and again until all 64 outputs are used by COM0. 

To help make this clear, I have highlighted the inputs (numbered COM connections) used for each topology and deleted the inputs (numbered COM connections) that are not available.  This means that every input (numbered COM connection) may connect to any one of the outputs (numbered channels) below it on the chart up to the next highlighted input (numbered COM connection).   All of these typologies are easy to work with and perform flawlessly.   Lastly the Independent topology offers maximum flexibility at the cost of heavy responsibility to ensure each relay in the desired path is correctly set.  This is more difficult to work with because there are so many more places that a mistake can be made for each path.