Andrea C

The data sheet indicates:  
Maximum input: 250 Vpeak DC to 60 Hz sine wave; 10 s per minute at maximum input on mA ranges (one-sixth
duty cycle)

Maximum common mode voltage (DC to 60 Hz sine wave): Electrometer, 500 Vpeak; V-source, 750 Vpeak

You may want to mount some protective diodes.  See attached from our Low Level Measurements Handbook.
Or download a copy:  Low Level Measurements Handbook

Can you let us know which version of KickStart you use?

The SourceMeter does not have slew rate or rise time control.
Instead, it implements a smooth first order response as it transitions to a new source level.
This allows best chance for no overshoots or ringing as it reaches new steady state source levels.

Hi,
Are you working with only two terminal devices?  In your original post it seems that might be the case.
Do you need to use more than one test frequency?

As you have discovered, when using bias tee, the mode needs to be managed during collection of the compensation values.  For nF and smaller, open compensation is most important.
You can accomplish that with just subtracting the open ckt measured value from your DUT measurement (at same test frequency).

The KXCI commands for collection and application of the compensation to measurements is implementing the same functions that Clarius gives for collection and use of compensation.  However, these are not expecting the bias tees.

Most of our 3KV HVCV installations are for three terminal devices (Ciss, Coss, Crss).  For this, we need different compensation values for each of the three measurements (due to cabling differences).  This influenced the ACS software implementation approach.

I have concerns about stacking up bias tees to address the issue.

 

When using the scan related commands, only one channel relay will be closed at a time.
If two or more channels are closed, the measured value will the combined ohms.

If the multiple closed channels is really what you need, you can close channels and separately command the dmm to measure.  You will need to also manage the backplane relays to connect the dmm to the switch hi and lo.

Are there any differences in the length of cables for your 20-channel setup vs. this one with only 5 channels?

If longer delay is allowing a good outcome, it implies a difference in the time constant of your DUT.

Does it stop reporting the overflow if you turn off the open lead detection?  The reported overflow could come a saturated measure range or from a detected open lead.  Since more delay fixes the overflow, this implies it is coming from the measurement from after the open lead detection has occurred.

To look into it, you might put a scope on the Card Sense HI and LO terminals.  When doing 4-wire ohms, the current is forced on the HI and LO and the resulting I*R is measured on the Sense HI and LO.
Is that spiking and requiring more settling time vs hte 20-channels setup?
 

For control of 3706A from .NET (C#), I'd suggest:

approach 1:  use a VISA layer and directly send the instrument commands (3706A Reference Manual)
approach 2:  use IVI driver.  This will leverage NI VISA runtime to communicate with the 3706A;  driver commands are translated to the instrument commands for you.

Both NI VISA and the IVI driver distribute some sample code in C#.

 

The Test Script Builder (TSB) software is giving a means to interact with the computer inside the instrument via the command API and scripting engine.  The only "file system" that has is the USB thumb drive on the instrument.

To have the data available in PC for saving to a CSV on the HDD:
try the internal web page of the instrument.  There is an applet for Extract Data (download buffers to CSV on PC).
Or move to Python or similar and read back the result of printbuffer() or print() commands.

Interesting.  I think it is related to the starting up into CC mode.
Datasheet does not tell us, but the output capacitance on the power supply is significant.
Slower V/sec slew rate will mean less displacement current.
How are you measuring the current in this setup?  Hi side or lo side of the 45Ω resistor?

If your concern is too much current when started up this way, some series R and use of the remote sense lines from rear panel could help.  Just mind the max 1V delta V between force and sense.

 

Need you to clarify on connections.  Where is the HI and the LO?

Your experiment sounds a little bit like Ion Beam Measurements.
Check out section 4.3.5 in our handbook:
Keithley Low Level Measurements Handbook

You may need to create a bias condition to attract the charge to flow through the amp measure function of the electrometer.