Using DAQ assistants in sequence to generate continuous wave

[mhouse1]

I need to generate a 3 phase signal that ramps up frequency and voltage from zero to desired value, hold that value until a button press and then ramp down the signal until zero.

i've created a VI that does this but i'm using 3 DAQ assistant's, 

1st : ramps up to desired value

2nd: loop at desired value until button press

3rd: ramps down to zero

the problem is that to transition from 1st to 2nd and 2nd to 3rd the 1st the DAQ assistant needs to stop to allow the 2nd DAQ assistant to start write to those channels; this results in a undesireable hic-up where writes to the analog channel stops.

is there away to continuously move between these steps without stopping?

[ToeCutter]

Yes, use DAQ assistant to generate a continuous streaming output. This will give you a template that allows you to write continuous data in blocks to the output. You can then use a state machine to generate your various waveforms and stream the correct section to the output in one continuous operation.

[mhouse1]

thank you,

the daq assistant generates a continuous streaming output right now. the only way to send new data is to stop the daq assistant and start it again.

are you trying to tell me to send data in blocks to the input of the daq assistant? how would i go about sending new input data without stopping the daq assistant? 

i'm guessing i need to set the daq assistant to continuous mode put it into a while loop and the state machine within the while loop selects which data? i've tried something similar with a few button and selection vi's to no luck.

[ToeCutter]

I don't have LV here to generate you an example. Don't confuse 'continuous' with 'continuous streaming'.

"i'm guessing i need to set the daq assistant to continuous mode put it into a while loop and the state machine within the while loop selects which data?"- yes this is exactly what you need to do.

You need to generate the correct kind of task with the DAQ assistant. IIRC, it's called 'continuous analogue output'. It will show a while loop where data is continuously written to the output. It may show a single block of data continuously being written, but you can modify it so the data written is modified each loop.

Post what you got (as a jpg or VI snippet) and mabe it will jog my memory.

[mhouse1]

i was able to do this without a statemachine, i needed to set the daq assistant to non regenerative mode. assign a local variable to the input of the daq assistant that is within a while loop. any time the data in the local variable is modified the waveform is updated.

thank you