Acceloration measurment with NI9234

[AK18]

Hi,

I am trying to set up a acceloration measurement with a accelerometer (PCB 352 C33) and the NI9234 - but I am getting confused with the settings in the DAQ Assistent.

At the end I need a speed value. Do I have to set up the channel for Voltage or can I use the velocity direct at the channel settings?

Thanks for the help!

Best regards,

Andreas

[deceased]

If the sensor is an IEPE accelerometer and you know the sensitivity in mVolts/mm/s then I believe you can directly measure using the velocity (IEPE) mode of the daq assistant.

[AK18]

Thank you for your response!

The sensor is a IEPE and I have the sensitivity for the acceleration (100 mV/g). But I still struggle with the other parameters, e.g. Signal Input Range, Iex Value, Iex Source, Terminal Configuration, ...

As soon as I have a proper signale I just have to convert it into m/s2 and integrate it onces to get to the velocity - correct?

Thanks!

[PsyenceFact]

Hi AK18,

If you are using an accelerometer, you should set your task up as Acceleration - IEPE, not Velocity IEPE.  You can set the scaled units to m/s^2 rather than g to avoid having to make that conversion yourself.  As you say, you can then integrate once to obtain velocity.

I believe the NI 9234 only supports +/-5 V input range so this is what the Signal Input Range should be set to.  The only Terminal Configuration available should be Pseudodifferential.

(Here's a note on the different types of terminal: https://www.maximintegrated.com/en/app-notes/index.mvp/id/1108)

Iex Source and Iex Value refer to the IEPE power supply.  "Internal" means it will be supplied by the NI 9234 at the current specified by Iex Value, usually 2.1 mA.  This is only available when usoing AC coupling.  You should check that this is compatible with your transducer.

Andy

[Henrik_Volkers]

Another hint: If you have access to the sound and vibration tools, there is an intergration vi provided that already includes a configureable highpass. This will avoid a runaway due to minor offset voltages you migth get.

The IEPE sensor has a HP , the DAQ has a highpass  and now you add a third one 😉  ... I would start with 0.07Hz ...

[AK18]

Thanks for all the responses - works fine!