6008 analog input - Illegal values

[LaserShore]

Hi,

Does anyone know how the 6008 handles invalid analog input voltage?  Specifically, what happens if the AtoD channel is setup for a 0 - 10 volt range and a negaitve voltage, (-19.0) volts is  placed accross the analog input?

I'm using the NI-DAQMx library, C/C++, library.  The call I'm using to set up the AtoD port is:

DAQmxErrChk(DAQmxCreateAIVoltageChan (taskHandle, AINPSTR, "", DAQmx_Val_Diff,0.0, (float64) s_dMaxAnalogInputVoltage, DAQmx_Val_Volts, ""));

where:  s_dMaxAnalogInputVoltage = 10.0;

and

DAQmxReadAnalogF64(taskHandle,1,1.0,DAQmx_Val_GroupByChannel,values,5,&nread,NULL);

to read the AtoD.

What would happen if any illegal input voltage is applied.  I know any is a large range, so I'm talking about something like -60 to +60 volts.

Thanks,

- Neil Shore

[SnowMule]

At ±60V, you're going to need to protect the inputs.

6008's overvoltage protection is limited to ±35V, with ±30V channel-to-ground isolation.

Scale it down (Resistor-divider works most of the time) before you feed it to the DAQ. 

[LaserShore]

Hi SnowMule,

Thanks for your response and the information!

In what document would I find the specification you mentioned?  It is not in the "User Guide and Specification", "3713031.pdf".

My question was more of a results question.  That is, would the DAQmxReadAnalogF64 function return the maximum range value or would it return an error?

Again, thanks for your response.

[SnowMule · Accepted solution]

Those specs are in the product's data sheet - link to it in the Specifications tab of the product page.

And no, there's no error generated when the input is out of range.  Scale the input appropriately so that doesn't happen; or if it does, your software recognizes that's higher than expected.

[LaserShore]

Hi SnowMule,

Thanks for your reply.

I guess I'll run some tests to "see" what happens.

[SnowMule]

Don't let the magic smoke out.