Signalling an external device when an AI is started and stopped, or in progress

[550nm]

Hello,

I'm trying to synchronize an external device with an analog multi-channel, multi-sample DAQ.

We are using the PCI-6132. When our AI task starts (via software) it begins watching a trigger-signal.

Once triggered, it acquires scans at the rate of an external clock1KHz. The triggers and clock are always there.

We have an external device that is also connected to the external clock. I need to signal the device when an AI is started/stopped, so that it only makes measurements while the DAQ is in progress.

Are there any signals available on this board, that I can route to the connector, which will indicate when an AI is running?

Thanks/Cheers.

[Kevin_Price · Accepted solution]

I think your best bet is to export the AI start trigger signal (named something like "/dev1/ai/StartTrigger") to a PFI pin.  That's an internal signal that pulses at the beginning of acquisition even when you don't configure for an external hardware trigger.

If necessary to create something more like an "enable" signal that toggles high for the duration of acquisition, you could do that with one of your board's counters.  Unless you know the finite # of samples you'll capture in advance, I'm not sure of a way to make the *end* of the pulse be in hardware-sync with the last AI sample captured.

-Kevin P

[550nm]

Hi Kevin,

Thanks, I looked at StartTrigger, but it's not much help without an "end" pulse. I forgot about the counters on the DAQ board - that might/could work.  Actually, if I had a trigger for every A/D conversion, that could also work.

Thanks for the counter idea - am looking into it now!