Multiple triggers for one AI

[JRRiquelme]

Hi!

I´m reading an analog signal triggered by a TTL signal.

Now i will have 3 different TTL signals and I would like the adquisition to start when the first positive signal arrives.

Is this possible?

Thank you for your help!

[John_P1]

What DAQ device are you using?

You can only configure a start trigger to use a single terminal.  However, depending on the device you could configure a digital input task with change detection timing which will generate a pulse in hardware ("Change Detection Event") when any of the three lines transition from low to high--you could use this pulse as your start trigger.

If you don't have a device that supports DI change detection, I would just OR the three signals together with external hardware and use the result as the trigger signal.

Best Regards,

[Henrik_Volkers]

Depending on your signal sources and the slope.... I would make a wired OR with some diodes (1N4148) and a pull down resistor, just like John proposed.