Unable to detect an analog trigger source

[d1sturbanc3]

I'm trying to detect a 5 V square wave attached to my analog trigger. The board is a NI PCI 4462. I'm trying to run the example VI "Acq&Graph Voltage-Int Clk-Dig Start.vi". I am getting this error.

Possible reason(s):

Measurements: An attempt has been made to use an invalid analog trigger source.

Ensure that the trigger source you specify matches the name of the virtual channel in the task or matches the name of a non-scannable terminal that the device can use as an analog trigger source.

Property: Start.AnlgEdge.Src
Corresponding Value: APFI0


Task Name: _unnamedTask<B8>

I tried different Trigger sources including APFI0, but I can't seem to get it running.

What I really just want to do is detect a trigger of 5 V and have a counter to count up. My current setup is that I have a source attached to channel 0, and a square wave attached both to the trigger and channel 1. I'm seeing both the source and square wave on both the channel, but I can't get the trigger to respond. Thanks.

[Hani R]

Hi d1sturbanc3,

If the 5V signal that you are using as the trigger is TTL compliant, then you can connect the signal to one of the PFI lines and have your Analog Input task trigger off of a digital edge.  If the square wave is not TTL compliant, you can trigger off of an analog edge but not from the PFI lines (you can use APFI0 if you are using an M Series device but not a DSA).  You will need to use one of the analog input channels (the channel should be configured in the task) as the Trigger Source.  Use the first channel in the analog input scan list to be Trigger Source.  Let me be a little more specific...

From what I understand of your application, you will want the 5V signal be both the input signal and the analog trigger.  Connect the 5V signal to channel 0 and the "source signal" to channel 1.  Configure the DAQmx Start Trigger to look for an Analog Edge and use channel 0 as the Trigger Source.  Set the desired Trigger Level and you should be able to run your program.

I hope this helps.