how to add delay between the Trig signal and the start of acquisition

[Ov_metas]

Hi,

I am acquiring a single chanel signal using a PXI 4461 board. The start of the acquisiation is triggered by a digital signal applied to the PFI0 input of the board.

I would like to know if it is possible to add a delay (for exemple an interger number of period of the 10 MHz clock) between the Trig signal and the start of the acquisition?

Playing with the pretrigger parameter (in number of point) didn't solve the problem because the delay (in time) is then dependent on the sampling rate...

I thank you in advance.

Frédéric

P.S.: I am using LabView 7.1 and the board is in PXI-1036DC chassis

[Christian Mergl]

Hey,

Yes, it's possilbe. You can use DAQmx Trigger property node with the following property:

Christian

[Ov_metas]

Thanks Christian,

I have had problem to find the "Star.Dalay" property, I had to change the filter of the property node !?

Anyway, I set the Start.DelayUnits and Delay property and started my vi...

I got the folowing error message:

"Error -200452 occurred at Property Node DAQmx Trigger (arg 4) in SimpleReadDetector&FFT_HardWareTrigger.vi

Possible reason(s):

Specified property is not supported by the device or is not applicable to the task.

Property: Start.DelayUnits

Task Name: _unnamedTask<C>"

Does the PXI 4461 board support this property ?

Frédéric 

[Christian Mergl]

Hey,

Yes, you are right, this is an unsupported property for this device, I'm sorry.

I tried to find another possibility but the only one I found was to just delete the first samples which would be in your delay

Christian

[Christian Mergl]

Hey,

Yes, you are right, this is an unsupported property for this device, I'm sorry.

I tried to find another possibility but the only one I found was to just delete the first samples which would be in your delay

Christian

[Ov_metas]

Hello! I am now back with my question how to add a delay within a Trig line. I know that it is not possible within the PXI-4461 board (using the PFI0 line). However, I have also a NI PXI-6652 board on the slote 2 of my PXI chassis and I successfully route the Trig signal form PFI1 (PXI-6652) to PXI_Trig1 of the backplane. The PXI_Trig1 signal is then used to start the acquisition of the PXI-4461 board. I thought the problem solved but I did not find how to add the delay between the "Trig in" on the PFI1 and "Trig out" to PXI_Trig1. The DAQmx Trigger property (Start.Delay) doesn't work because the PXI-6652 doesn't support DAQmx but only NI_Sync :-(( Does anybody have an idea how to put a delay between the Trig in and Trig out ? I thank you in advance. Frédéric