Andrea C

When using LAN based connection to KXCI, it is normal for every config command you send to respond back with ACK\0.
Pg 2-11 in the KXCI Remote Control Programming manual shows ethernet based write and read examples.

For example, sending ME\0 command, the 4200A will respond back with ACK\0

In your code, if using LAN to KXCI, plan to do a write + read for every operation to pull the ACK\0 off the bus.

I think you are just having a lot of backlogged ACK\0 in the output queue that need to be read and this is why you do not get expected response to the SP or the DO commands.
 

In datasheet for the 2380, pg 3 Specifications, it lists the minimum operating voltage.
Suppose you have the 2380-500-15 model and using the low current range (3Amps), the min operating voltage is 0.6V at 3Amps.  It increases to 4.5V at 15Amps for the high range.

This means when operating in CC mode and pulling 3Amps, the 2380 will develop a voltage drop of 0.6V between the HI to LO terminals.  Think of the 2380 as using the output stage of a FET to control the CC mode.
This voltage drop could be attributed to the I*Rds of that FET plus other I*R drops in the path inside the 2380.

Consequently, your device that is supplying the current cannot have a voltage potential lower than this minimum operating voltage of the load.  The load needs to be able to develop at least the minimum voltage drop in order to maintain the CC set point.

In situations where you want to test your device at voltages lower than the minimum operating voltage, use an external (linear) power supply in series with your device.  One floats on the other.
Use the remote sense lines to still measure the voltage only from your device rather than device + external supply.

Otherwise, the entry of the max and min voltages during CC mode should be influenced by the I*R drop and open circuit voltage of the device that is suppling the current to the load.


 

Hello Maia,

That is very odd behavior.

I see you have the latest firmware, A14.

What if you manually operate the instrument from a reboot/factory defaults?  Does the current range adjust appropriately then?

As you increase the source voltage a little bit, does the 200pA range ever report overflow?
If you have a volt meter or scope channel, what does the 2V output do as you approach full scale 200pA and push past?

Seems like the :MEAS:CURR? rather than a :READ? will be needed.

How is your remote connection to the instrument?  Looks like you have a LAN to something converter?  Using GPIB or RS-232 on the 6517B?

What is your exact model and firmware level?  The response to a *IDN? command will tell us.

For the delay, are you talking about the stime parameter?  Or the delay inside the my_wait_complete().
Of course, if the my_wait_complete() loop rate is very slow relative to the speed of the Source-Measure sweep, then it will be slow to detect the exit condition.  In the sample as posted, it uses 50msec loop rate.

What parameter values do you use when calling the ExitCondition_SweepVLinMeasureI(smu, startv, stopv, stime, points, current_limit, lowest_range) function?
And at appx what voltage and currents are you expecting the exit to occur?

Keep in mind, during the active trigger model sweep and during the my_wait_complete() loop, attempts to interact with instrument from the PC will be blocked.  This is why the logic of an exit condition is moved into the TSP code.

As for ACS, it is doing a for/next loop and able to check for compliance at each iteration.  These are implemented as functions in the TSP runtime memory on the instrument so there is no required bus traffic to the PC for each iteration of the loop to decide about exit condition.

 

Should Sense HI also be guarded?  Ideally, yes.

In concentric conductors like a triax cable, is easy to envision the minimization of leakage currents from the signal on center pin if the next layer inner shield is driven at same potential by the guard.  No delta V = no current.
This is one motivation for guarded cable especially for the Force HI.

But guarding has additional benefit of smaller effective RC time constant if the coupled capacitance between the layers does not have any charge up requirements.  This would be the reason to also guard the Sense HI line.
The input R of the Sense HI is typically > 10GΩ

For long cables, you might find some settling time benefit by guarding depending on the speed of your IV curves, size of dV steps, etc.

Looks like your Python code was written for different product than the model 3706A.
You are sending SCPI syntax commands.
The 3706A is TSP command set only.

:SENSE:FUNC "VOLT:DC"  becomes dmm.func = dmm.DC_VOLTS

See if the attached Getting Started document helps you.

In KickStart, the AutoZero check box control results in turning it ON or OFF (dmm.autozero = dmm.OFF).

It is not using the auto zero once setting.

In addition to the 2450 related accessory, the 1100V model 2470 has similar one:  2470-1100V-BAN.

I see no reason not to operate them in reverse, e.g. plug the banana into rear of 2410 to present triax.

Take note on how the LO and Sense LO are handled if intending to use 4-wire connections.

Info about 2470-1100V Accessories

The male triax ends are mechanically compatible with the rear panel HV triax connectors on model 2470.
But they are also compatible with our more legacy triax such as the 237 related barrels, tees, 7078-TRX-x, CS-630, etc.
You may need some 237-TRX-BAR barrel connectors.

 

So, your terminal 4 is not at GND potential?<br> How big might the voltage at terminal 4 become?<br> <br> I do think you will need a floating amp meter where the LO is not shared with other SMU in 4200.<br> An external 2400 or 2600….. or even Amps terminals of a DMM depending on the values of current.<br> <br> Can you use known small resistor between terminal 3 and 4. &#160;Use a SMU at each terminal too.<br> Both SMU force 0 Amps and measure V. &#160;Your current is (V3-V4)/R<br> <br> A third SMU sweeps V at terminal 1.<br> Terminal 2: &#160;GNDU or use a SMU to force 0V and measure the current flowing into the SMU. &#160;Be sure to set the current limit high enough for all the current that will arrive.

See if this helps. &#160;The code should apply to any 2600A or 2600B.<br> https://forum.tek.com/viewtopic.php?f=224&amp;t=142633<br> <br> &#160;