DMM measurement can't move forward

[AhGang]

Hi

    I am using PXI 2532 and PXI 4071 to measure voltage. Handshaking between the two is used.

    When I input scan list as below, it works and DMM can measure 5 data: (I configure DMM Trigger Count as 1 and DMM Sample Count as 5. PXI 2532 Repeat Mode is Finite.)

    /PXI1Slot5/r0->c0 & /PXI1Slot5/r1->c2;

~/PXI1Slot5/r1->c2 & /PXI1Slot5/r1->c3;
~/PXI1Slot5/r1->c3 & /PXI1Slot5/r1->c4;
~/PXI1Slot5/r1->c4 & /PXI1Slot5/r1->c5;
~/PXI1Slot5/r1->c5 & /PXI1Slot5/r1->c6;

     But if the scan list is as below:

/PXI1Slot5/r2->c0 & /PXI1Slot5/r2->c4 & /PXI1Slot5/r2->c6 & /PXI1Slot5/r2->c8 & /PXI1Slot5/r2->c10 & /PXI1Slot5/r2->c12 & /PXI1Slot5/r2->c14 & /PXI1Slot5/r15->c2 & /PXI1Slot5/r5->c14 & /PXI1Slot5/r1->c2;
~/PXI1Slot5/r2->c0 & ~/PXI1Slot5/r2->c4 & ~/PXI1Slot5/r2->c6 & ~/PXI1Slot5/r2->c8 & ~/PXI1Slot5/r2->c10 & ~/PXI1Slot5/r2->c12 & ~/PXI1Slot5/r2->c14 & ~/PXI1Slot5/r15->c2 & ~/PXI1Slot5/r5->c14 & ~/PXI1Slot5/r1->c2;

   In regard to the second scan list, DMM shall be able to measure 2 data. But it only can measure 1 data.(I configure DMM Trigger Count as 1 and DMM Sample Count as 2. PXI 2532 Repeat Mode is Finite.)

   Actually my application needs scan list configuration like the seconde. The first is the one I  wrote for handshaking study before.

   Why?

   Thanks.

[AhGang]

I found the root cause but I am not sure.

In the second scan list, the actions in the second step are all disconnections.

It is likely the if the actions don't include even one connection, the switch will not send out trigger. Is it right?

Why I set the second step to be disconnections is that I want to make sure all connections are disconnected after one test.

This is also take me to another question:

Is it true that the switch will disconnect all connections after the task is cleared?

Thanks.

BR 

[chericks1]

Hi BR,

I've reproduced the issue, and I'm looking into why this occurs.

In reference to your second question, clearing the task returns the switch to the state it was in before the task was started.  If all the crosspoints were disconnected before the task was started, then these crosspoints will be disconnected upon clearing the task.

Hope this helps!

Chad Erickson
Switch Product Support Engineer

NI - USA

[chericks1]

Hi BR,

The issue you found is the expected behavior of the switch module.  NI switch modules are IVI compliant, and the IviSwtch Class Specification (attached below) states the following on page 60:

Notice that only path connection events generate scan-advanced triggers.  Disconnecting a path will not generate a scan-advanced trigger.

Let me know if you have any further questions.  Best regards,

Chad Erickson
Switch Product Support Engineer
NI - USA