Continuosly add plots in same xy graph and auto clearing of the data for each new run

[amritadey.ph@iitkgp.ac.in]

Hi everyone!..

I am using keithley 2612a dual source meter to measure FET characteristics. The two channels of the meter are providing voltage supply to  the gate and drain respectively. Now my target is to vary gate voltage(Vg) from 0 to 10 V(say) and for each sweep of the gate voltage drain voltage sweeps from 0 to 5V (say). I want to observe the drain current(Id) vs drain voltage(Vd) on a XY graph for each gate sweep in a single run of the VI.

But the problem I am facing is that the previous  plots are not ereasing at the time of each new run. The graphs start plotting on the previous data from the previous VI run.And also for each time gate sweeps the Id Vs Vd curve retraces back from its final value!

How can I clear the previous history at the time of each  new run?

[GerdW]

Hi amritadey,

I would start with initializing each shift register!

(Cleaning up would also help to identify bd objects already connected by wires…)

[amritadey.ph@iitkgp.ac.in]

Hi,

Thanks for the reply

Previously I tried by initializing each shift register.  Though the initialization of shift register helps

auto clearing of the graph for each new run but it wouldn't help me to get

continuos id vs vd plot for each different sweep of Vg. I want a plotting  like the attached file.

Kindly see the new attachment.

[GerdW]

Hi amritadey,

you need to initialize the register sooner or later! Right now they continue to collect data forever…

Options:

- Initialize when the VI runs first.

- Connect the shift registers of the inner loop to shift registers of the outer loop. Initialize the outer loop's shift registers…

[altenbach]

All you need is the "build xy graph"* express VI. Set it to retain data between calls and reset it on the first iteration. No extra code needed.

*you get that automatically if you place the xy graph from the express palette

[amritadey.ph@iitkgp.ac.in]

Initilization of shift register will not help me to store plots from each iteration of the loop which is my aim.

I didn't initialize the inner shift registers because I want to store the plots in the same xy graph

from previous iteration of the while loop. Now the problem is since I haven't initialized them, the initial value of

shift register is becoming the last value from the previous iteration. Therefore the plot is not starting from 0 or default x axis value in the next iteration but instead start from the final value of last iteration.

Is there any way to get each plot starting from default x value,

from every iteration to see in the same graph.

[altenbach]

You have full control what x values to add at any state of the program progress.

As a first step you should untangle the code and eliminate all these stacked sequences. They just chop up the program and make it very hard to maintain and debug. Also the DAQ parts seem very inefficient. Do you really need to initialize and close with every iteration of the loops?