Load impedance setting for PXI 5412 in C

[ASIM_BHATTI]

Hello

I am using NI PXI 5412 waveform generator in C++. I am facing some problem in getting some clean and stable output from this card as its output is continuously fluctuating. One option i want to try is to set its load impedance to some higher value (>>50 ohm) as i have to use it with a higher impedance load.

I tries these routines for setting its load impedance in C but it did not work

ViReal64 load_impedance=200000.0;

checkErr(niFgen_SetAttributeViBoolean(vi, "0",NIFGEN_ATTR_LOAD_IMPEDANCE,load_impedance));

checkErr(niFgen_SetAttributeViSession(vi, "0",
NIFGEN_ATTR_LOAD_IMPEDANCE,load_impedance));

Kindly help me

[kirsch]

I am facing some problem in getting some clean and stable output from this card as its output is continuously fluctuating.

This doesn't sound good. Are you looking at the output without any DUT connected just using an oscilloscope? Or are you connected to something?

Try the Soft Front Panel to generate a signal and look with a scope without any other loads connected to the device, in order to rule out programming errors. If the output doesn't look solid, you may have a hardware issue.

[ASIM_BHATTI]

I have not connected any load and have just connect PXI-5412 output to Oscilloscope using standard NI cable. I had tested this card with NI FGEN Soft Front Panel in the start where this problem was realized.

[kirsch]

It sounds like you need to call NI support and look into RMA due to faulty hardware. If you have another 5412 you could compare to make sure that one works.

[ASIM_BHATTI]

Hi Kirsch

Thanks for help. One thing i could not clearly explain in my first post is that these routines of C i mentioned are causing programming error and i am not able to run them in my C code. In other words, currently i am not able to change my PXI 5412 output impedance from default 50 ohm to mega ohms (Oscilloscope input impedance).

Currently i am bothering how to change my load impedance using C routine? Once tested with PXI 5412 high load impedance set, if issue does not solve, i have to call NI support

Thanks

[ASIM_BHATTI]

Hi Kirsch

Thanks for help. One thing i could not clearly explain in my first post is that these routines of C i mentioned are causing programming error and i am not able to run them in my C code. In other words, currently i am not able to change my PXI 5412 load impedance from default 50 ohm to mega ohms (Oscilloscope input impedance).

Currently i am bothering how to change my load impedance using C routine? Once tested with PXI 5412 high load impedance set, if issue does not solve, i have to call NI support

Thanks

[kirsch]

Can you change it in the SFP? If yes, open NI I/O Trace to get a good sense of what functions it calls.

Regardless, I still wouldn't expect the output to be unstable.

I will leave it to the appropriate support experts to follow up since they are better qualified than I am with these. Good luck!