Trigger stopped working on PFI0.

[wilvil2000]

Normally when something like this happens to me, I try to backtrace what I've done since it last work. I've had no luck.

I am using LV 6.1, NI-DAQ 6.9.3, PCI-6071E with an SCB-100.
NI-DAQ - configured AI to Differential bipolar +-10volts. I am using named channels. Current(0-5v)[0], Pressure(0-5v)[1], BL1(0-1v)[2], BL2(0-1v)[3], and BL(0-1v)[4]. I want to trigger of channel "Current".

LV - I am using "Current" as the first channel in my channel list. I am using PFI0 for the trigger channel. I am pretriggering to collect 1000 samples. I am collecting a total of 41000 samples. That is slighly more than 2 seconds worth of data.

Problem - This used to work a couple of days ago. Now it doesn't. I don't know what changed.

My soluti
on - I wired channel 0 "Current" to PFI0 directly. This allows the trigger to happen.

Question - I thought, that PFI0 connections where done automaticaly by LV when you selected PFI0 on the trigger channel control. Obviously I am missing something here. Could someone explain to me how to programmatically set the PFI0 to by the trigger channel. Also, if all else fails, Im I wrong by using a physical wire to trigger PFI0?

[raeletro]

If you want to use the PFI0 as trigger, you need to connect some signal to the terminal,otherwise, the board will wait for something on the PFI0 terminal and nothing comes out.

But if you want to use some specific channel as the trigger, (channel "Current" in your case) you can specify the trigger config to watch for this channel instead of PFI0.

I hope it helps you undestand.

[Filipe A.]

Hello;

You didn't mention what trigger type you are catching, analog or digital.

Anyway, since you configured PFI0 to be the trigger channel, you will need to have a valid signal physically connected to the PFI0 pin. If the trigger you are expecting is digital, you need to validate the pulse that is coming to PFI0, with a scope maybe, to see if it is meeting the TTL standards.

In case you are expecting an analog trigger, make sure you set the trigger level to a value that will be reached by the analog signal connected to PFI0.

Hope this helps.
Filipe A.
Applications Engineer
National Instruments

[wilvil2000]

So let me see if I understand this.

The trigger I am trying to catch is analog.

So, I selected PFI0 as my trigger channel, therefore, the PFI0 terminal (#38 in my case)HAS to be wired to my channel 0 (Current - terminal#3) if I wanted to trigger of the analog level from that channel's input.
And this wiring from channel 0 to PFI0 can not be done programmatically by the board and LV if multiple channels are acquired.

Would this be correct?

[raeletro]

Yes you are correct.

But again: if you want to trigger your signal by an analog channel, you just need to configure the trigger function to wait for a trigger at desired analog channel, instead of select the PFI0. Does it make sense to you ?

Ricardo

[wilvil2000]

That makes sense but it appears that LV doesn't allow me to select a particular channel as the trigger channel when acquiring multiple channels. It looks like you can only use the PFI0 terminal.

Is that also right?

[raeletro]

Take a look on the vi AI Trigger config.vi. THis vi is located on the advanced pallete of the Analog input Vis.

Ricardo