PXIe-5171R External Trigger Using NI-Scope

[AgentYellow]

Hi there,

using the 5171R with NI-Scope works fine for me, when I'm using one of the channels as a trigger. According to the device specification (and the help of the NI-Scope trigger source), the bidirectional PFI-Ports of the AUX I/O could also be used as a trigger source. Actually I can only choose between Channel 0-7 and an External TRIG (with value VAL_EXTERNAL). Can some one tell me what "physically" pin/connector the External Trig is referring to or how I can assign one of the PFI 0-2 lines?

Best regards,

Philipp

[balexand · Accepted solution]

Quick question: Are you using LabVIEW?

The trigger sources that you mentioned (Channel 0-7 and External TRIG) are for analog triggers only.

In order to use PFI lines for a trigger, you need to specify that you are using a Digital Edge Ref Trigger.

See the attachment.

External TRIG is not available on the 5171R.  It refers to the TRIG input on digitizers such as the NI PXI-5114, PXI-5122, PXI-5124, PXI-5152, PXI-5153, or PXI-5154.

[AgentYellow]

Ok now it's really obvious...

Thanks a lot!

[vmanoj]

Hello sir,

IN Pxie 5170R scope card,

With this Resource, http://digital.ni.com/public.nsf/allkb/CE386F124372DD2786257EA500530798?OpenDocument            I am able to Acquire analog signal from channels by triggering through one of the PFI line.

 But when it comes to the case where I need to use two separate PFI lines for two separate analog channels the sample code (Multirecord Acquisition) won't help me.

Can you suggest me with some better way to do this.

Thank you for your help !!!

[balexand]

Hi,

I would suggest moving your question to a new post.  The subject of this post refers to NI-SCOPE, but it sounds like you are using the Reconfigurable Oscilloscopes SW product.

The Multirecord Acquisition sample project shows how to acquire multiple channels of data simultaneously, using one timing engine.

Since there is only one timing engine, there is only one set of start/advance/reference triggers.

To come up with a good solution, we'll need more information about the requirements.

Why do you need to use multiple PFI lines?

Do you need to acquire measurement data from multiple analog channels simultaneously, or is it acceptable to acquire records from one channel at a time?

At what point does software get involved?  What portions of the acquired data need to get fetched on the host computer?  Would it be acceptable to have software reconfigure the active channel?

One option that might suit your use-case would be to always write all applicable channels of data to the Multirecord Acquisition engine, and write multiple timestamps: one for each PFI trigger.

This document will briefly explain the timestamp interface:

http://zone.ni.com/reference/en-XX/help/374500A-01/oscopes/idl_mracq_fpga/

timestamp specifies the timestamp associated with a particular record. The number of timestamp values per record written to the Write VI must match the timestamps per record input on the Configure Acquisition VI in the Multirecord Acquisition host library.

Although stored timestamp values are guaranteed to be correlated with records, they are not correlated with individual samples in those records. The application that uses the Multirecord Acquisition FPGA library must provide sample-level timestamp correlation, if required.

If you do not write the required number of timestamps for each record, the record acquisition process stalls, which may eventually cause a write overflow condition.

The timestamp interface allows you to store arbitrary meta-data associated with the record.  You could find a way to encode information, about what time each PFI line was asserted, in the timestamps, and then reconstruct that information in your host software.

[vmanoj]

Thank you so much for your suggestion. As you said I posted my question in new post

Please go through this..

http://forums.ni.com/t5/High-Speed-Digitizers/How-to-modify-Pxie-5170R-quot-Multirecord-Acquisition-...