Ty McKinney

Hello Gerhard,<br> You will not be able to get the 2450 to operate in a constant power mode as your resistance changes over time.<br> The closest that you could achieve with this instrument is to set a source value and compliance value and have those variables remain fixed throughout your test, as Power (P) is equal to your current (I) multiplied by voltage (V) P=I*V, this would imply a constant I and constant V. If you expect your resistance to change this would violate Ohm's Law, V=I*R.<br> If your resistance is expected to change, your I or V would need to adjust accordingly throughout your test. With the 2450 you can choose to set one of these functions as the constant source function, and the other would adjust according to your resistance, then you could measure your resistance.

The screen shot function on the touch screen SMUs are a front panel operation only. The closest you can get to something along this line would be to save all of your data, export it, and graph it manually. Also, you can screenshot the screen manually by pressing and holding the HOME and ENTER buttons on front panel.

Hello,<br> Unfortunately, we do not spec the parasitic capacitance of those cables or connectors.

Hello,<br> See the link below for a LabView Driver for the 2450.<br> <br> https://www.tek.com/en/support/software/driver/keithley-2450-2460-2461-2470-native-labview-2015<br> <br> Also, here is the reference manual which will include instructions on how to make front panel and remote current measurements as well as a list of ALL available commands for communicating with the 2450.<br> <a href="https://www.tek.com/en/keithley-source-measure-units/keithley-smu-2400-series-sourcemeter-manual/model-2450-interactive-sou">Model 2450 Interactive SourceMeter Instrument Reference Manual | Tektronix</a><br> <br> Hope this helps!

This error you're experiencing could be related to one of two things: Either the preferred USB to GPIB adaptor requires 488.1, hence no error when you're sending SCPI commands over that protocol, or NI-MAX/LabVIEW is configured for 488.1 rather than SCPI.<br> The 2400 provides either 488.1 or SCPI as options depending on what your drivers/software/adaptors ask for.

What card are you using for the DAQ6510 resistance measurements?

Hello,
Can you attach a copy of your code please?

READ and TRAC:DATA are very different commands.
READ will send an INITiate and FETCh? command to your unit. What this will do is initiate your trigger model and fetch the data from one triggers worth of data, most of the time it will only give you the LATEST data point.

TRAC:DATA following and INIT command will read back the entirety of your buffer.

That being said, there should not be a difference between the measured values numerically if you use either command, which is why I'd like a copy of your code to see if there is anything causing this large difference in data you are seeing.

Ref attached PNG for above post

Are you using the scripts in Appendix A and B of that application note? One thought is that the data here is returned as binary floating point data, it has to be converted to ASCII. If the measurements are right on the box, then likely something is being converted incorrectly. Do you format the data when you write it to the file like in the python example in Appendix A(see attached PNG)

That formats it as a floating point with 4 decimal places and exponent notation.

Hello,
Connect the instrument to the pc using USB. Then I would recommend downloading and installing NI-VISA, then try with NI-VISA Interactive and see if your instrument is discoverable and allows communication between unit and PC.
Open NI-VISA Interactive and see if the instrument appears.

If this is successful, open Test Script Builder and press Open Instrument button.
Click the Select or Enter New Instrument button.
Look in the list of resources for anything that looks like this USB0::0x05E6::0x2614::nnnnnnn::INSTR (where nnnnnnn is the serial number of the unit). This would be your unit. Select it and send *IDN? to see if unit is able to communicate.