cascade power smu 4130

[GhostCole]

Hey,

I'm trying to cascade two pxi 4130 (power smu) by needing at least 28 volts forsomething else. After wiring those two pxis, I found a Problem : by using labview as shown on the picture below, after generating 14 V for the first and 14V for the second, I'm obtainning 21V on my external mutimeter (instead of 28) AND on the indicator, it is also 28 BUT by using the NI DCPower Soft front pannel, I obtained 28V so could you help me find where this lost comes from ? Why do I have 21 instead of 28 on my multimeter ?

Thanks 😉

[JÞB]

Stick this in there:

AutoRange default is Off the SFP sets the range to whatever the voltage level needs - you don't

[GhostCole]

Thanks Jeff, 

I tryed with the property node, but it generated another error 

[JÞB]

Yeah.  you need to add active channel to make that p-node work as intended and wire it just like the other vis (no hardware here so I can't test it).  or just use the set voltage level range

 

and set the range before you set the voltage level.

[GhostCole]

I tried, but same problem ! 

Do you have a labview example of  tow cascaded power SMU (NI PXI 4130) ? 

Thanks for helping 

[Taki1999]

Order matters.

The Active Channel has to be above your Autorange setting.

Property nodes get set top down.

[JÞB]

And set the range BEFORE you set the level!  That property node needs to move much farther left on the block diagram.

[billko]

In general, do the steps in the same order you would do it if you were to set it up manually.

[GhostCole]

The good new is that my VI is now working, but I still have a question (sorry 😛 ) : Why do I have 22V on my multimeter instead of the 30V as shown on labview ? 

[JÞB · Accepted solution]

You know.  A snippet would really help much more than the attached pngs.  Just edit select all (Ctrl+A) and Edtit>>Create snippet from selection

You are still setting the range after setting the level but that's not your problem.

You are seeing 22V on your meter because the SMU outputs are not in series (Wired wrong) If they WERE in series the currents would be identical.  Kirchoff's Laws cannot be violated.