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Change detection signals routed to counter via PXI backplane

Hi,

I am a newbie in PXI backplane signals routing/triggering.

I have questions about how to route change detection signals from a PXI-6528 digital I/O board via the PXI backplane to the counter(s) on a PXI-6711 AO board.

I want to be able to choose between the 24 input signals of the PXI-6528 and then measure signal period, frequency, duty-cycle etc using change detection triggering of the counter.

The frequencies are low, 0-100 Hz.

I'm using LabView 7.1 and NI-DAQmx 7.3 and I have tried some of the examples in NI example finder without success.

My HW setup is PXI-1044 chassi with PXI-6528 in slot 4,5 and PXI-6711 in slot 6.

Should I use the PXI_triggers and how do I configure them?

Connecting terminals or exporting signals?

I would appreciate an example, a step-by step instruction or a hint in right direction.

Best regards

Bernt

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Hello!

Some more information about this type of applications can be found here:

Measuring the Time Interval Between Changes on the Digital Lines
http://digital.ni.com/public.nsf/websearch/D8DBEF68ED57639586256C910061479E?OpenDocument

The above document is written for traditional NI-DAQ but the same is of course possible to achieve in DAQmx as well. 

Check out the shipping example called 'Read Dig Chan-Change Detection.vi' and add a VI called 'DAQmx Export Signal.VI' between DAQmx Timing and DAQmx Start with the following input parameters 'Change Detection Event' to the Signal Input and 'xxx/PFI9' to the Output Terminal where xxx is your device name for the AO board.

Regards,

Jimmie A.

Applications Engineer, National Instruments

 

 

Regards,
Jimmie Adolph
Systems Engineering Manager, National Instruments Northern European Region

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Hi Jimmie A.
 
Many thanks for the help.  Now I'm on the track again.
 
Below I noted my experiences if anyone else has the same problem.
 
I had to export the change detection signal via PXI_Trig0 on the PXI-6711 AO board and also set the counter CI.Period.Term propertiy to PXI_Trig0. Otherwise DAQmx complained that the PFI9 already was already in use (error code -89137) when configuring the counter to measure the period of the signal. See the enclosed screen dump.
 
-89137 "Specified route cannot be satisfied, because it requires resources that are currently in use by another route."
Best regards
 
Bernt Hansson
 
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Hello!

I am very happy that it worked out well for you.

Regards,

Jimmie A.

Regards,
Jimmie Adolph
Systems Engineering Manager, National Instruments Northern European Region

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