Current excitation source

[lester14]

When I enable the IEPE property for the IEPE accelerometers, I found that there are three different types of current excitation sources: internal, external, and none. What does this mean? How to decide whether it is internal or external? Is the internal or external refer to the device which is connected to NI? Suppose I have a IEPE accelerometer which has a built-in amplifier, should it be set to internal or external? Thank you.

Lester

[Broken_Arrow]

"Internal excitation" means that the NI DAQ device will supply excitation voltage to the accelerometer. In order to do this, you have to be using a NI device that is capable of supplying excitation, such as a signal conditioning module.

Setting it to "External excitation" tells LabVIEW that you are wiring an external power supply to your accelerometer for excitation.

Message Edited by Broken Arrow on 08-16-2009 07:12 PM

[lester14]

Thanks for your explanation.

So when it is external excitation, do we need to set the value of excitation current? Since it is supplied by another device, not Labview. Or the value in Labview in this case is only to tell Labview what is the current. It would not supply power to the accelerometer.

[Broken_Arrow]

You are correct. Regradless of how you excite the sensor, LabVIEW wants to know what the value is so that it can do scaling for you if you ask it to.