daq mx read signal greater than max range

[gomarq]

Hi everyone!

I am using NI-4300 and i was wondering what happen if I acquire signal greater than max input range.

I have set the range +/-5 V, and +/-10 V and I dont see any differences when I acquire a 6V signal.

Thanks in advance.

[crossrulz]

I know many measurement devices will go slightly above the rated range.  But I wouldn't expect a full volt above the 5V range (that's 20%).  Are you sure there isn't any clipping?  Which terminal block are you using?

[gomarq]

I am using TB-4300.
If i set the range -10/0 it also measure positive values.

[JesusG]

Hi gomarq,

as far as the NI-4300 specifications manual is concerned:

http://digital.ni.com/manuals.nsf/websearch/173D788886E46B37862576D3005222D9

this board has the following fault protection:

Between AI+ and AI–.................±60 V

Between any AI and COM..........±60 V

Between PFI or RSVD lines

and COM.....................................±24 V

Input current during

fault conditions ................................±5 mA max/AI pin

It CANNOT support overvoltage during long periods. You have to set the board range according to the level of the signal you expect to acquire. If you set a range of 0 to 10V and you acquire 15 volts during several seconds, your board will be damaged and you may be hurt too. So, I do NOT recommend to do such thing. If your signals are over range, you will have to attenuate them before the 4300 acquisition.

I hope this helps!

Jesús

[Henrik_Volkers]

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@gomarq wrote:
I am using TB-4300.
If i set the range -10/0 it also measure positive values.

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Have you checked the ACTUAL range used (selected by the driver)?

[gomarq]

Thanks
I have solved the problem. The range selected by the driver was diferent, I thought that i could set any range.