LabVIEW
Simultaneous DAQmx Tasks
Greetings,
I'm still learning the ins and outs of DAQmx and have run into a bit of a problem with code running on my USB 6008.
Using NI's State Diagram Toolkit, I have a State in which I'm acquiring analog data from two channels. I was able to configure a Task in NIMax to do this easily. However I also need to monitor a digital input in this same state to capture a time value.
The code as I currently have it crashes LabView completely as soon as the digital input is triggered. I'm guessing I probably need to add this Task to the analog acquire. But I'm not quite sure how to do this, or if it's even possible.
The only other approach I can think of is to begin my data acquisition in one state, but not wait for it's completion before moving to another. I'm just not sure how to do this.
As always there's a big time crunch. Any input greatly appreciated.
I'm still learning the ins and outs of DAQmx and have run into a bit of a problem with code running on my USB 6008.
Using NI's State Diagram Toolkit, I have a State in which I'm acquiring analog data from two channels. I was able to configure a Task in NIMax to do this easily. However I also need to monitor a digital input in this same state to capture a time value.
The code as I currently have it crashes LabView completely as soon as the digital input is triggered. I'm guessing I probably need to add this Task to the analog acquire. But I'm not quite sure how to do this, or if it's even possible.
The only other approach I can think of is to begin my data acquisition in one state, but not wait for it's completion before moving to another. I'm just not sure how to do this.
As always there's a big time crunch. Any input greatly appreciated.
Unfortunately there is no error code as it's Windows that is shutting
down LabView. (You know, the "would you like to send a report"
crash)
I'm acquiring 1000 samples at a rate of 1000/second on two channels, while at the same time watching a digital input.
There's no problem acquiring the analog data. But something about that digital input is taking LabView right now. The interesting thing is that it doesn't crash until the digital input changes state.
I started experimenting with moving things in and out of that particular "State". But had no luck before I had to jump back onto something else that was "hotter".
My guess is that I still can't have two tasks starting at the same time, whether they're of different types or not. The problem here is that I can't seem to figure out how to add the digital input to a "multi" task.
I'm acquiring 1000 samples at a rate of 1000/second on two channels, while at the same time watching a digital input.
There's no problem acquiring the analog data. But something about that digital input is taking LabView right now. The interesting thing is that it doesn't crash until the digital input changes state.
I started experimenting with moving things in and out of that particular "State". But had no luck before I had to jump back onto something else that was "hotter".
My guess is that I still can't have two tasks starting at the same time, whether they're of different types or not. The problem here is that I can't seem to figure out how to add the digital input to a "multi" task.
I thought it should work too Stuart. The analog task in the
diagram there is configured to acquire 1000 samples on each of two
channels over one second.
The digital task is setup as 1 sample, on demand. This is how I've setup triggers in the past and it's always worked.
What's really odd is that I'm not getting any LabView errors at all. It just crashes completely. Usually something has to be pretty messed up to do that.
The digital task is setup as 1 sample, on demand. This is how I've setup triggers in the past and it's always worked.
What's really odd is that I'm not getting any LabView errors at all. It just crashes completely. Usually something has to be pretty messed up to do that.
Thanks for the reply Hal.
This is the latest (still incomplete) version of the code I'm running.
There are still many portions of this code that are incomplete, so the error I'm getting could very well be caused by something I've not had a chance to look at yet.
I've included the Max config file with the global tasks defined. I've also used some OpenG VIs in this code that I can also post if required.
Hopefully I'll have some more time to spend on this today.
This is the latest (still incomplete) version of the code I'm running.
There are still many portions of this code that are incomplete, so the error I'm getting could very well be caused by something I've not had a chance to look at yet.
I've included the Max config file with the global tasks defined. I've also used some OpenG VIs in this code that I can also post if required.
Hopefully I'll have some more time to spend on this today.
I wanted to reply while the topic still has some life in it.
Unfortunately my inexperience is going to show badly here, as I'm really having trouble manually configuring the tasks that I'm using. I'm reading the documentation and struggling with it. I can't predict when I'll "get it".
The actual problem I'm trying to solve is this:
One digital trigger will start a timer, and begin acquiring 1000 samples over one second.
When the second digital trigger is tripped, the time since the first digital trigger occurred needs to be recorded. It also needs begin acquiring 1000 samples over one second.
Then I need to do some post process analysis on the data acquired from both channels. In this case I'm finding the max peak, and the time it occurred.
I'm using the State Diagram Toolkit and perhaps this is part of my problem. I can't seem to visualize how to begin acquiring on one channel while still waiting to begin acquiring on another. It's very possible that both channels will be acquiring at the same time. But it's also possible that they won't be.
Unfortunately I'm the only one in our shop even attempting to use DAQmx, so I'm on my own for this one. (I'm not even sure if this device will work under traditional DAQ)
I'm going to to continue to struggle through what documentation and examples I can find. But I'm starting to get that "Mime in a box" feeling.
I'm just not sure what to try next.
Unfortunately my inexperience is going to show badly here, as I'm really having trouble manually configuring the tasks that I'm using. I'm reading the documentation and struggling with it. I can't predict when I'll "get it".
The actual problem I'm trying to solve is this:
One digital trigger will start a timer, and begin acquiring 1000 samples over one second.
When the second digital trigger is tripped, the time since the first digital trigger occurred needs to be recorded. It also needs begin acquiring 1000 samples over one second.
Then I need to do some post process analysis on the data acquired from both channels. In this case I'm finding the max peak, and the time it occurred.
I'm using the State Diagram Toolkit and perhaps this is part of my problem. I can't seem to visualize how to begin acquiring on one channel while still waiting to begin acquiring on another. It's very possible that both channels will be acquiring at the same time. But it's also possible that they won't be.
Unfortunately I'm the only one in our shop even attempting to use DAQmx, so I'm on my own for this one. (I'm not even sure if this device will work under traditional DAQ)
I'm going to to continue to struggle through what documentation and examples I can find. But I'm starting to get that "Mime in a box" feeling.
I'm just not sure what to try next.
