PXI 6229 counter triggering

[haari]

Hi All,

I am new to triggering concept.I am using PXI-6229 M-Series DAQ card.

In my application, I am doing the below steps:

1. I am configuring a counter (ctr0) to generate continous pulses

2. I am generating digital pulses on one of the PFI(PFI9) lines.

3. I have connected PFI9 to the gate input of ctr1

4. I am configuring ctr1 to start counting the edges of ctr0 , only when it receives rising edge on PFI9.(PFI9 is the Digitaledge trigger src,Digitaledge trigger edge is rising)

The problem I am facing is ctr1 is counting the edges of ctr0, though there is no rising edge on PFI9.(ctr1 is not waiting for trigger)

How much time counter waits for trigger? Is there anything wrong in my application flow or whether I have to do any settings in s/w or additional connections in H/w?

Please suggest solution for this.

Thanks for your help.

Regards,

Harika

[Kevin_Price]

There's a non-obvious special rule for counters.  You can use a normal start trigger for pulse output tasks.  But for input measurement tasks, you need to use an "Arm Start" trigger.  This can't be configured with the DAQmx Trigger.vi, you have to use a DAQmx Trigger Property Node.  If this doesn't resolve your problem, post back.

-Kevin P

[haari]

Hi Kevin,

Thanks for your response.

As you suggested, I am trying to use "Arm Start Trigger" for counter input measurement. I need a small clarification on h/w connections. I am connecting Arm start trigger source signal to the gate i/p of the respective counter.Is this correct ? or any other h/w connections i have to make, please suggest me.

Waiting for your reply.

Thanks,

Harika

[Kevin_Price]

The best thing to do is to specify the source of the "Arm Start" trigger on the DAQmx Trigger Property node.  It is probably fine to be physically connected to the counter's default gate pin, but remember to program the task to "look there" for its Arm Start trigger.  When you drop down the additional property, you'll need to specify the signal in terms of the corresponding PFI #.   Under MAX, you can find documentation to correlate physical pin #'s with PFI #'s and functional descriptions (source, gate, out, etc.)

-Kevin P