Filtering VISA read buffer string using Filter(Express VI)

[nooboist]

I have a problem sending VISA read buffer strings to an filter express VI. That aside, i also have problems sending the same buffer read strings into a part of our code that can calculate heart rate. A constant value of "-Inf" is always being displayed. Chart values are from 0-1023. Any attempts to use feedback nodes/shift register cause the VI to timeout (memory issues?). Please help! Regards, Love Labview

[billko]

I'm having a problem driving my car.  See how vague that sounds?

State specifically what issues you are having, and upload the broken code, too.  🙂

[nooboist]

Oops that must have sounded silly 😕 Ok i've uploaded multiple approaches we tried to use. For some reason the read buffer from the Visa Read won't interact with our calculations 😞 Thanks a many!

[GerdW]

Hi nooboist,

please get your VISA read clear: who told you to use a "data bits" property node in your code? It's plain wrong!

You have the TermChar enabled so use VISARead with a sufficient big constant (like "99") as byte count to read!

- There are better ways to build a file path. Use file path functions!

- There are better ways to build an array: use BuildArray!

[nooboist]

Hi GerdW,

I have disabled the TermChar and changed the property to read no of bytes at port. Allow me to explain a little the GUI. When I run the code, the information will be saved to a file in which data will be appended to the existing file. 

I am getting a PPG waveform signal and I would like to insert a digital filter in the code. However, adding a bandpass filter screws up signal. Without the filter, the code seems to be unable to process the signal as well to achieve a heart beat calculation even though the conversions look like they could work. Attached is the new VI. Any help would be greatly appreciated! 

Sincerely

Nooboist

[GerdW]

Hi Nooboist,

can you supply typical measurement data? Best would be a graph containing typical data set to default…