I am trying to use a Keithley 2400 SMU to take a measurement after a specific time period, how can i achieve this. I need to apply power, wait 1.5 seconds (or change this time period down the line) and take a measurement. The timing is important here because I need to take a reading of an exponential decay. I would like to have the instrument decide the timing because that seems like it would be more consistent that relying on windows/labview.
A little more description of then entire experiment/program design would get you better advice.
Basically, you have a few options
- If timing isn't that critical (+-10ms) then LabVIEW can be used to trigger the measurements. Vary the measurement timing as needed. Use the Keithley internal clock to get the actual measurement time. The flexibility of this method is the timing can be varied on the fly and you can read back data immediately, but you loose in timing accuracy. (EDIT - See how I implement this for a Keithley 2450 here - https://forums.ni.com/t5/Instrument-Control-GPIB-Serial/Keithley-2450-Continuous-current-measurement.... You could do something similar for 2400, possibly using an array of measurement intervals.)
- If timing is critical (+-1us) then you need to use the internal timer, buffer measurements to memory at a constant interval and then read everything back. In this case you loose flexibility, you are confined to a single interval between measurements. You will need to look at the manual to understand the limits of this method. (i.e. max delay, timing jitter, max # readings in memory, etc..)
Either of these solutions can be achieved by looking at the examples that come with the LabVIEW driver. In the first case its a For loop and timing logic and in the second its implementing the trigger VIs.
Hope that helps,