keithley 2400 & 2635 synchronous run

[zhanxiaohong1314]

Hi, 

I am a beginner  and  am not  familiar with labview. I met a problem recently. I use keithley 2400 offering 5V voltage to measure current and use keithley 2635 offering pulse current. I want they synchronization operate.The attachment is the written  program,please help to slove the problem.

Thanks

[cstorey]

That's a monster block diagram.  It could use a lot of clean-up, and simplification.  But before that can you explain what you are trying to accomplish?  

From your diagram there is no data flow that synchronizes the K2400 and the K2635, so they both operate as fast as they can independently.  

It looks like you want to test a laser diode.  So you want to sweep pulsed current and record current and voltage readings for the LD using the K2635?  What is the K2400 doing during the sweep?  Just providing 5Vdc bias, or do you also want it to collect reading from a detector for each K2635 step?  Do you have external triggering already setup or are you fine with software triggering?

[cstorey]

If you want to synchronize the k2635 pulse with a k2400 current measurement, then you will need external triggering - its the only way since pulse happen too fast to trigger the k2400 in software.  Keithley provides cables for K2400-2400 triggering, but I'm not sure if they have inter-series version (K26xx to k24xx).  You might need to use the DIO on the K2635 to the input of the K2400 trigger link.  Ask Keithley about that.

First you'll want to configure the k2400 to measure on the external trigger.  You've done that in your code and it looks adequate.  

In terms of diagram clean up, here's an example of how I do a pulsed voltage measurements with the K26xx.  Simple enough to convert to current.   One subvi configures the source and measure features of the SMU, the other parse the return string from the buffer.  Note this is a single voltage point, you just need to loop through all current values you wish to measure.