I'm having trouble creating a square-wave DAC output. I'm using the U6 pro.
I've set a timer with the desired duty-cycle to FIO0 and would like to do the same for DAC0, however it doesn't seem like a timer can be set to a DAC channel. I need FIO0 and DAC0 to be synchronized, so a 'wait' technique as suggested in the 'Wave form generation' app note doesn't seem to be relevant.
I'm using MATLAB.
How can I synchronize DAC0 to match the timer?
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I think the best solution will be to use an op-amp to amplify the PWM from FIO0 to the desired voltage level.
There is no internal mechanism to allow a PWM to be output to a DAC. T-series devices could do this with a Lua-Script, but there would be a few microseconds of phase lag.
Hi,
Thank you for the quick answer. Unfortunately, for the intended purpose of this project, I have to create a squae wave on the DAC that will be synchronized with the same square wave on a digital hannel.
Is there any way to do so using the u6?
Follow - up question:
I'd like to take input measurements only when the output square-wave signal is 'on'. Is there a way to synchronize the acquisition with the output timing? Also - How can I store such measurements?
an example for clarity:
output signal is 'on' -> start acquiring data -> output signal is 'off' -> stop aquiring data and store the measurements->repeat.
How fast are all these things happening? Frequency of outputs? Sampling rate of input? How many channels of output and input?
Why are you a making a square wave with DAC0 rather than just using 2 timers?
output frequency - 256 hz, with 0.51% duty cycle (about 20 us 'on' and 3.98 ms 'off').
one input channel, with sampling rate of 1khz (can be changed).
DAC - because i've been requested to do so, otherwise I would have used two timers.
It sounds like you have seen the waveform generation app note:
https://labjack.com/support/app-notes/waveform-generation
The only solution that I see possibly working for you is stream-out on the T7.
With AIN0, DAC0, and FIO_STATE, you have 3 channels so your max scan rate is 100k/3 = 33.3 kscans/second. That means your timing resolution is 30 us.
With AIN0 and FIO_STATE, you have 2 channels so your max scan rate is 100k/2 = 50 kscans/second. That means your timing resolution is 20 us. FIO_STATE lets you update up to all 8 FIO with a single channel so could get 2 rectangular outputs using this single channel.