ni9225 minimum voltage

[jb112454]

In the specification sheet it says that the minimum voltage is 294Vrms is this correct? I need to measure DC voltages between 0 and 100 would this module work? I realize that rms is both AC and DC but you could be a little clearer in the specification sheet that the module is both AC and DC or is it?

Thanks

[Lea_D]

Hi jb,

The NI 9225  is a 3 channel, 300 Vrms Analog Input Module. As you mentioned, the specifications manual states 300 Vrms as the typical operating range and 294 Vrms as the minimum operating range. This is just the range that the device will be operating within. You'll be able to put in and measure 0-100 Volts DC values and read out the DC value.

[faisaldin]

Hi Lea D,

It means that NI-9225 can input DC voltages upto 424 V  as (300Vrms = 424 V peak) . Am i right?....... kindly provide me the input DC voltage ranges 

One another thing that is not in the specifications or i might not seen is..... what is the sensitivity of this module (minimum input voltage that can be sensed in)

Thanks

[johnsold]

The specifications indicate that the input coupling is DC. The scaling coefficient is ~51 uV/LSB.  So that suggests that the resolution is that size.

There does not appear to be a specification for DC input voltage range. The overvoltage protection is nominally at +/-450 V but no accuracy is specified. One consideration is the power dissipation in the input circuitry.  The power dissipation in a resistor is the same when the DC voltage equals the RMS voltage for a time varying signal.  The power dissipation at 450 V is more than twice that at 300 V.  To be safe, I would not apply any DC voltage larger than 300 V.

Lynn