accelerometer presence

[Aitortxo]

Hi all:

I'm working with accelerometers,

I read them with a NI-PCI-4472

Everything works fine except I can't manage to detect that an accelerometer is not connected, or broken.

Having in count that accelerometers are feeded with an excitation current, there should be an easy way to detect.

I have been trying DAQmx VIs, but had no fortune. Could anyone help me, please?

Thanks in advance,

[JaimeC]

Hi,

I think I give you this soltuion also by phone but anyway...

DSAs outputs can work with AC or DC coupling. If using DC coupling you will see the 4 mA of the excitation multiplied by the internal resistance of the sensor. That would be a DC offset voltage.

Because of that, the common configuration of the DSA is AC coupling, to avoid those offset and just observe the signal changes.

In this case DC coupling could be useful because if the sensor is present it would measure that DC offset, but if the accelerometer is not present that would be a wrong measurement (saturation or ground) because there is no sensor and its like an open circuit.

Then the solution i give you is to make a measurement with DC coupling first before starting the acquisition just to know if the sensor is present (reading offset voltage) or not (saturation or ground). After that you can programmatically change to AC coupling and make the normal measurements.

Regards,

Jaime Cabrera

NI Applications Engineering Spain