Additional DC offset using external voltage source on PXI-5441

[LV_Usr]

Hello All,

Hope you are doing well.

I am having a concern while adding DC voltage using external source on PXI-5441. I have a requirement of 0 to 5V square wave pulse with variable frequency, duty cycle and phase angle. I could have -2.5 to 2.5 V signal using PXI-5441 but not the one I need. So I am looking to add some additional DC voltage to my waveform but before that I am looking to confirm whether I need any extra protection circuit for PXI-5441 or in built protection should be fine?

Thank you.

Regards,

DG  

[santo_13]

Could you please share the connection schematic of how you intend to add this DC offset to the output externally?

Just to make sure you don't feedback voltage back into the instrument and thereby damaging it.

[LV_Usr]

Hello,

I am looking forward to use PXI-5441 in series with DC power source, assuming the output of the PXI-4551 is isolated from earth ground. Also I am looking to add only 2.5VDC externally which I have tested using Agilent waveform generator and works fine. But I am not sure about PXI-4551 hence looking to check if anyone has such experience with PXI-4551.

Thanks.

[santo_13]

The outputs are not isolated from Earth ground. If it is just 2.5VDC you can configure the offset of the output of the signal itself and need to take this extra effort to series connect a power supply.

[LV_Usr]

Hello,

Yes, it was my first preference but PXI-5441 allows only 1.250VDC offset on 5Vpp signal. I guess, max allowed offset is 25% of Vpp signal. Do you think adding 2.5VDC externally will be fine for PXI-5441?

Thank you.

[santo_13]

Actually, it states +/-25% of the amplitude range and not the amplitude of the signal.

You can also switch to a higher range such as the High Gain Amplifier path.

If you use the High Gain Amp path with a 50ohm load, you can add up to +/-3V offset to the signal and this satisfies your 2.5V offset requirement.