dc coupling with NI 9234

[serbring]

Hello,

I have to carry out some acceleration measurements. I need low frequency components of the accelerations (from 0 to 10Hz) so I have thought, that it is better use the accelerometers in DC coupling. I have NI 9234, is it possible to use that one in DC cupling? I have seen on  the product page, and it seems supported, but when I try to set DC coupling labview signal express 2009 returns me this message:

AI channels on this device do not support using DC coupling while using IEPE excitation.

I'm using Bruel 4520 accelerometer.

thank you

[serbring]

Hello,

I have to carry out some acceleration measurements. I need low frequency components of the accelerations (from 0 to 10Hz) so I have thought, that it is better use the accelerometers in DC coupling. I have NI 9234, is it possible to use that one in DC cupling? I have seen on  the product page, and it seems supported, but when I try to set DC coupling labview signal express 2009 returns me this message:

AI channels on this device do not support using DC coupling while using IEPE excitation.

I'm using Bruel 4520 accelerometer.

thank you

[MarcoMar]

Dear Serbring,

I need some informations to help you

please can you post the following:

- The VI program you are trying to use

- DAQmx version

- Error code number

Many THX

[MarkGrot]

The error description is correct.  You must disable IEPE excitation to use the module with DC coupling, which will likely not work well with your accelerometer.

[serbring]

Hello,

I'm using that accelerometer  http://www.bksv.com/products/transducersconditioning/vibrationtransducers/accelerometers/4520.aspx

So I have to change accelerometer for using DC coupling with NI 9234 module, isn't it?

Is there another module that permit me to use DC coupling with that accelerometer?

Thank you

[MarcoMar]

Dear Serbring,

If you would answer my previous questions I could help you, otherwise I can't do it without those informations.

[serbring]

---

MarcoMar ha scritto:

Dear Serbring,

I need some informations to help you

please can you post the following:

- The VI program you are trying to use

- DAQmx version

- Error code number

Many THX

---

Hello,

1- I'm using labview signal express

2- I'm using cDAQ NI 9178

3- error -201172

I hope it is useful for you.

regards

[MarcoMar]

Excitation current Source is INCOMPATIBLE with DC measurements (how can the measuring device know what part of the DC current is the excitation one and what part is the measured one?).

If you need to do DC measurements you have to set Iex Source = None.

If your sensors need an excitation current, they won't work in DC mode.

Regards,

[serbring]

Thank you, I have another question about iex source and Iex value. What do they mean?

[MarcoMar]

Iex is the value of the excitation current 

[serbring]

thank you, so if I need the dc coupling on an accelerometer, I have to put Iex source=0 and Iex source=none if the accelerometer is powered by an external battery?