Min Logging Rate too fast

[norton920]

Hi.

Hoping that someone can advise on a logging rate issue that we have.

We use NI Max (bundled with Labview 2016) to capture data from a NI Chassis with (typically) a NI9207 card fitted. The connected instruments vary but can include Linear Displacement Transducers, String Pots and Inclinometers. 

As far as I know the NI software has a minimum logging rate of 783Hz which is way too fast for what we need. Is there any way to log at 1 to 0.2Hz?

Thanks

Richard Norton

[GerdW]

Hi norton,

As far as I know the NI software has a minimum logging rate of 783Hz which is way too fast for what we need.

Please provide the source of your "knowledge"!

(AFAIK you can easily set lower sampling rates!)

Is there any way to log at 1 to 0.2Hz?

Yes: just configure your DAQmx task to such low sample rates!

The specs of your NI9207 give conversion times of 52ms (high-res mode) or just 2ms (high-speed mode), so you get at max 500Hz sample rate with this module!

[aptivo]

You could as well average your signal with a moving average filter and save the values after e.g. 500 values.

[norton920]

You are correct. No issues in setting lower rates (down to 1Hz) when using 'Measurement and Automation Explorer' in stand alone mode.

I think that the issue may be the way in which the NI s/w interfaces with the test machine control s/w.  The test machine is a servo hydraulic crush rig that is controlled using Tiab s/w.  

I also note that I cannot capture data in my 'Measurement and Automation Explorer' task.  It appears that the task needs to be used in a 'development environment'  (?).

When running the test rig the task does generate a tdms data file so I'm guessing that there is some level of communication between the Tiab s/w and the NI task.  The log rate issue may be due to this communication link.

Can we use the task with Labview to generate the required tdms file?  If so that might be a solution although time syncing the machine control system data and the NI chassis connected instrument data may be an issue. 

[GerdW]

Hi norton,

using 'Measurement and Automation Explorer' in stand alone mode.

What is this "stand alone mode" of MAX?

the issue may be the way in which the NI s/w interfaces with the test machine control s/w. The test machine is a servo hydraulic crush rig that is controlled using Tiab s/w.

Which NI s/w interfaces are you talking about?

What is that "test machine control s/w"?

What is "Tiab s/w"?

I also note that I cannot capture data in my 'Measurement and Automation Explorer' task.

MAX is used to handle/organize NI DAQ hardware.

It appears that the task needs to be used in a 'development environment'

Yes. Usually this will be LabVIEW.

When running the test rig the task does generate a tdms data file so I'm guessing that there is some level of communication between the Tiab s/w and the NI task.

The same task that you checked with MAX?

Again: what is this "Tiab s/w"? Are you talking about a DAQmx task when you write "NI task"?

Can we use the task with Labview to generate the required tdms file?

When you talk about DAQmx tasks: yes.

Your message is missing a lot of (background) information. This way I cannot give much advice…

[_Bryan]

It sounds like you did not write the software and now you want to modify the sample rate.  Have you talked to the person/company who wrote the software about the changes you want?  Depending on how the program was written will depend on what changes need to be made for your desired sample rate.