PXI5411 Generates DC Voltage

[LIONCSU]

HI:all
I Program PXI5411 to generate DC Voltage. The output value is normal less than 5V,but the output value is abnormal over 5V. The output value dropdown then jump up the expected value! I hope the DC output value increases from 0 to 10V smoothly. Would you help me?
thanks!

[Shea C]

LIONCSU,

Are you sending a signal to the 5411 that ramps up to 10V or are you simply generating static DC voltages? Can you elaborate on what you are seeing and what functions/examples you are using to generate the signal? It sounds like the output drops and returns back to the expected value when outputting DC values greater than 5V. Is this correct? If so, how long does it take for the voltage to stabilize. Are you applying and DC offset or attenuation? Unless the 10 dB attenuator is switched on, which occurs when the gain is less than 1.58 V or the amplitude is less then 3.16 Vpk-pk, the waveform maximum plus the offset must not exceed ±5 V into 50 Ω if it does, the waveform is clipped.

Regards,

Shea C
Applications
NI

[LIONCSU]

Shea C
Thank you reply my question. I use the example of niFgen_Basic_Std_Waveform_Example.vi in LV.The item of DC is selected form WAVE option. Output value is controlled by DC OFFSET. The output Value is sampled by PXI4472. It clearly displays the tendency as mentioned above. I couldn't know how to process the case of "attenuation" . May I elaborate on the problem? I hope receive your ANSWER.
Thanks!
Regards,
LIONCSU

[Shea C]

LIONCSU,

It may help to understand the the issue you are seeing if you assume the device is an arb and not a powersupply. Looking at the device from the perspective of an arb is the best way, as it reflects what the hardware actually does.

The output of the 5411 and 5401 has a maximum gain of 5.0. And the maximum value for DC offset is equal to 1/2 of what ever the current gain is. So, if the gain is 3, the maximum DC offset is 1.5. When a DC voltage is requested NI Fgen uses a combination of gain and DC offset to acheive the desired voltage. To help minimize glitches in the changing of the attenuators, the output is disabled while the change is taking place. I hope this explains the issue that you are seeing as it is expected with this device.

Regards,

Shea C