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How to use SMB trigger input on PXI-8187 in LabView


I have PXI-8187 controller instaled in PXI-1031 and two PXI-4071 digital multimeters. I want to trigger mesurement with external trigger. One way is to used AUX port on DMM, another can be TRIG input on PXI 8187 CPU unit. Is possible to use this possibility in LabView 7? How?

Best regards!
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Message 1 of 11

The simplest method of triggering your 4071 is definitely by using the AUX connector on the front panel of the DMM. However, you do have two other options.

Of the alternatives, your best choice is to employ a Timing and Synchronization board (PXI-665x). I've linked the product page below. These devices allow easy and very flexible routing of the timing and triggering signals from, to, and between PXI chassis.

Timing and Synchronization Hardware

The final option, as you mentioned, is to use the PFI connector on the 8187 controller itself. There does exist beta, currently unsupported, software for LabVIEW that will help you to use the SMB connector (it's also not extremely easy to install). If you'd like more information, please let me know what your email address is.


Alan L
Applications Engineer
National Instruments
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Message 2 of 11
Send me please this software on toni.verdenik@talum.si
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Message 3 of 11
I would also like a copy of this software please.

It is a bit disappointing that such a potentially great feature for the bulk of the users that simply need a trigger and would like to have a simpler system without an extra card are left out on a limb.

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Message 4 of 11

Could you also email the beta vi.

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Message 5 of 11
There are multiple reasons why this is not a supported feature for triggering under Windows and why NI does not recommend using the controller's SMB connector for this purpose. National Instruments has hardware that was designed specifically for extremely accurate clock generation, synchronization, and triggering between PXI chassis (PXI-665x) and other recommended alternatives listed below.

Non-deterministic propagation delays
1. The controller's SMB input is not guaranteed to have a defined propagation delay to the backplane. This means the SMB trigger on the Windows PXI controller is useless for customers that want deterministic triggering. Unlike our PXI-665x boards which have a maintained API and precise triggering properties, the PXI controller's SMB connector and routing circuitry is intended for Watchdog use under LabVIEW RT and isn't designed for this use case. A trigger propagating through the SMB circuitry and going to the backplane, or vice-versa, could have a great deal of variance in the propagation delay which makes gathering useful triggers impossible. This propagation delay is not something National Instruments specs.

An excellent available workaround: Use the measurement hardware's trigger inputs
2. The triggering inputs on our measurement hardware (that customers likely have in their system) can route triggering signals to the PXI backplane (usually through PFI lines) with deterministic results. This functionality is fully supported in most of our APIs and will be maintained between generations of devices.

NOT backward or forward compatible
3. The SMB input is NOT guaranteed to be compatible between different versions of our PXI controllers under Windows. The hardware properties along with an excellent workaround are the reason we do not support doing routing of triggers through the SMB connector on our PXI family of embedded controllers under Windows. If you are still interested in the beta software despite the shortcomings, visit www.ni.com/support and submit an e-mail request.

Adam Ullrich
PXI/VXI Product Support Engineer
National Instruments
Message 6 of 11
OK, I will route my trigger through my PXI7831R DIO and synchronise through the chassis synchronisation.
Thanks for taking the time to give a detailed explanation
Message 7 of 11

i would like to use the SMB Trigger of my pxi 8187  as an output.
I explain my problem:  i 'm studying the offset existing between the threads (write of one characters on two buses) in order to correct it. But  this offset is not the same every time. So i decide to take the clock of my timed loops as reference and to do it , i must take my clock signal on the SMB connector of my pxi 8187 .

2 questions :

- How to manage in taking my clock signal (from the Create Timing Source.vi) to send it on the SMB connector?
- How to do , to retrieve my signal from the SMB connector to an oscillospoe or a logical analyser ?

I don't know if i have succeeded in explaining my problem and to illustrate it , i give you an example of my VI


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Message 8 of 11
Hi TheGame,
Unfortunately, there is not a good way to route triggers out the SMB input of PXI controllers.  I have heard it can be done, but it is not supported or tested by National Instruments, so I cannot provide too much assistance.  Hopefully, somebody who has done this before can help.  I encourage you to file a product suggestion at www.ni.com/ask if you feel this feature would be useful in your application.
Best of luck to you!
Chris R.
Applications Engineer
National Instruments
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Message 9 of 11

Can I have the beta vi enables me to use the SMB trigger input on PXI-8187 in Labview .


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Message 10 of 11