U3+LJTickDAC Streaming input and sending analog output signals simultaneously | LabJack
 

U3+LJTickDAC Streaming input and sending analog output signals simultaneously

4 posts / 0 new
Last post
D_B
D_B's picture
U3+LJTickDAC Streaming input and sending analog output signals simultaneously

I would like to stream input voltage and set output voltage at the same time without interruptions of the input stream, using Python on windows 10. 

I tried to achieve it with a threading, but with no success. So far the only solution for me was to send requests and apply GoOne, but a time resolution of reading the input is not sufficient. If possible, I would like to use LJTickDAC, but it is not necessary.

Is it possible and if it is, how should I do it?

LabJack Support
labjack support's picture
Yes, you can update an LJTick

Yes, you can update an LJTick-DAC using command-response while a stream is active.  The typical method is to update outputs once in your stream read loop right after the stream read call.  For example, say you are using ScanRate=1000 and NumScansPerRead=100.  That would mean your stream read loop executes every 100 ms and that is how often you update the outputs.

Note that the T7 has a Stream-Out feature where it can update outputs in stream mode:

https://labjack.com/support/app-notes/waveform-generation

D_B
D_B's picture
Thank you!

Thank you!

However, I have faced an unexpected problem - for some reason, all the AIN terminals now have constant 1.26V on them, even if I send hard reset command or unplug and plug back the device. It didn't happen before, and I was using my old code that used to work, when I noticed that.

Do I miss something in the datasheet about it or it may be hardware problem?

LabJack Support
labjack support's picture
Please do the following basic

Please do the following basic test:

1.  Remove all connections from the U3-HV except USB.

2.  Jumper AIN0 to GND and jumper AIN1 to VS.

3.  Run LJControlPanel and look at the test panel.  Channels jumpered to GND should read near 0V and channels jumpered to VS should read near 5V.  Floating high-voltage channels (AIN0-AIN3) will read near 1.4V.

https://labjack.com/support/app-notes/floatingunconnected-inputs