trigger on continuoutsly acquired data

[thames]

Hi

The digital i/p for the project is low at all times except when user manually toggles it high

I am doing the foll steps

1) continously acquiring one line digital input of the DAQ device

2) converting digital input to analog

3) trigger when analog value is >2V (i.e when digital i/p goes high, digital high is 5v) 

I am getting "dt<=0 error" for trigger step

My intention is to get "data ready" from the trigger step when i/p goes high and perform some tasks inside a conditional repeat as long as "data ready" is true

I have atached the project along

Thames

[sahpe]

Hello Thames,

What are the tasks you need to trigger? Depending on what they are there may be easier ways to achieve this.

Otherwise, I would advise to raise that limit to over 3.5V, as 2V is actually an undetermined state for 5V TTL. A logic low is between 0V and 0.8V, and a logic high is usually between 3V and 5V.

The error you are seeing is probably due to your extremely low rate. "5m" means your acquisition is running at 5mHz, or 5milliHertz. Is this what you need? This is giving your acquisition waveform a dt of less than can be used, hence seen as below 0. Try increasing this.

Kind Regards,

Michael S.
Applications Engineer
NI UK & Ireland

p.s. this is much easier in LabVIEW!