T7 DAC0 waveform data point values

Thanks for your reply,

Just to clarify what you said, please let me know if the following statements are correct, and answer some of them:

 -> So DAC0 output for T7 ranges from 5V(~4.97) to 0V. So if I send a value of 2.5 to the STREAM_OUT0_BUFFER_F32, I get a voltage output roughly      near 2.5V.

 -> What is the maximum resolution of voltage values passed to STREAM_OUT0_BUFFER_F32 (since float 32 is for binary values, not for voltages)?            Conversely, if I am sending voltages(decimal values) to STREAM_OUT0_BUFFER_F32, how do I interpret STREAM_OUT0_BUFFER_SIZE_BYTES       (mentioned as 512 bytes in the datasheet)?

 -> To get a better waveform (low noise and resolution), which one is better - sending voltage values to STREAM_OUT0_BUFFER_F32 or sending binary        values to U32 and/or U16.

Thanks,

rohanl

Hello,

I would appreciate if you give me some guidance as to how to use the stream out0 buffer using a LJTick DAC0 output expansion module.

I want to stream voltage values (now in +ve and -ve voltage ranges) to the DAC0 using LJTick module.

Is it possible to use the stream buffer to do the same?

Thanks,

Rohan L

Ok. Thank you so much.

So from this information, do I conclude that waveform generation using a DAC is not possible using a LJTick module?

If not, is there an alternative to generate a waveform (in positive and negative voltage range) by sending values to the LJTick fast enough(typically every 5 msec).

Appreciate your help.

-Rohan L

Ok. Thank you.

Can you suggest a few URLs to the "Software Timing, Command Response Updates" technique to update the LJTick DAC to create a waveform?

Thanks,

Rohan L

Hello,

On which block can we connect a LJTick DAC module to use more than four TDAC addresses? In other words is there a way to connect more than two LJTick DAC modules to a single T7 pro?

Since on a T7 pro there are only two blocks with FIO0/1 and FIO2/3, so 0 and 2 would correspond to all even TDAC# and 1 and 3 would correspond to all odd TDAC#.

Thanks,

Rohan L

I need help with accurate timing output on LJTick module. I am sending voltages to the Labjack which are in the range of +/- 5V to create a waveform. I am using LJM library since the project is mainly python based.

However, consecutive voltage samples sent to the LJTick have to be spaced by 5 ms(with minimum error). Since I cannot use stream out buffer(which is having really good timing accuracy)with LJTick, I am using delays for 5 ms interval between sending two voltage samples to the LJTick. I can either use a delay provided by python (time.sleep() or equivalent, which is not accurate below 15 ms) or use WAIT_US_BLOCKING.

But the WAIT_US_BLOCKING gives a variable delay depending on which machine the script is played, (as the command is in between other commands which are processed at different rates by the python interpreter), and this is not as accurate as streaming method.

Is there a way to generate a waveform on a LJTick with timing accuracy of the streaming method? Or do consider this as the ultimate shortcoming of T7 pro?

Please let me know my options.

-Rohan 

Hello,

Based on your previous reply, can you please elaborate how a Lua script can be coupled to a python script running on the PC to update the LJTick DAC every 5 ms?

Since my voltage values going to the labjack are held in a list in a python script, is there a way to load the Lua scipt with those values through python to update the LJTick DAC?

Thanks,

Rohan L