Keithley 6517a -ve voltage loop not connected and PWM.

[karan_maverick]

Hello. Attached is the lab view code for V-I measurement without monochromator, which you have developed.

Now there are two things in this code which need to be fixed. Without any understanding of what has been done in depth it is quite difficult for me to improve the code. Although I am trying.

1. The Minimum voltage is not connected to to the circuit and hence is set to the default value (0 V). If it is known that how it can be connected then the display can be changed to negative voltages.

2. The Voltage and the current loops are in the same plant. They need to be separated for PWM to be put in the voltage loop.

3. Similarly, PWM with changed valued will give hard switching.

I haven't found the connection in the original code also.

Regards

Karan

[Mr.F]

Hi Karan,

Can you point me to where you downloaded this instrument driver? It’s missing a lot of subvis.

Thanks,

Matt

[karan_maverick]

Dear Matt

Hello. Thank you very much for your quick answer. We downloaded this driver from the labview website as driver for Aesthetically Labview 8. Then we manipulated the driver as per our needs as without or without monochrometer.

However, In the original driver also the negative loop is not connected and the current and the voltage plants are the same and hence PWM cannot be made without separation of voltage and current loop. The PWM has to go into the voltage loop.

However, I am stuck at these steps.

Most gratefully, kindly could you look into this.

Regards

karan

[Mr.F]

Hi Karan,

Sorry, but this file still does not have any subvis. I searched ni.com/idnet and could not find this instrument driver anywhere, can you tell me where on ni.com/idnet I can download this instrument driver?

[karan_maverick]

Dear Matt

Greetings. I am attaching the labview driver for keithely 6517 A. I am also attaching my program "I-V plot time and without monochrometer" and example vi's that I found on the discussion group.

If you see my program "I-V plot time and without monochrometer" , in the block diagram that following things are not connected.

1. The Negative voltage input to the main block.

2. PWM to the voltage loop. Also, voltage and current loops are same, they need to be isolated for PWM block to be put in.

In similar examples, if you see the vi file for Keithley 6517A Single read Examplesmod , the input dc voltage is 0+-100V but on changing 0 to -1, the value is moded to 1.

In the  test sequence example the negative input voltage for diode leakage is not being accepted.

I suppose that this is because of for function syntax, which does not accept negative increments.

In my program "I-V plot time and without monochrometer" , the minimum voltage is connected . I need to connect it to be able to give negative input voltage values.

I am attaching the picture of the block diagram of the program and the desired output graph.

Could you kindly advise on how to connect the minimum voltage (to get negative voltage on the display and the keithely display)  and the PWM.

Also, if I am not clear that could you tell me a direct number to reach you and your convenient times. So that I can explain it to you in words.

Regards

Karan Behar

[Mr.F]

Hi Karan,

I checked ni.com/idnet for the driver for the keithely 6517 A. Unfortunately, I see that this driver was not developed by NI and is hosted on the website “as is”. That being said, have you looked at the manual for your device? You could find that appropriate command in the manual and incorporate that into your code. Are you getting any specific errors that you need help understanding or you trying to add to your code and are stuck? Unfortunately, we don’t give out our direct lines on forum posts.

[karan_maverick]

Dear Matt

Greetings. I have been through the  manual of Keithley 6517 a.

Unfortunately haven't found anything very specific there.  I am attaching the picture of the block diagram of the code. In this you"ll see that the minimum voltage input is not connected to the main plant. Hence it takes the default of the voltage to be 0. I want to connect this, to be able to put negative voltages.

Unfortunately all my attempts have been in vain.

Please advise.

regards

Karan

[Mr.F]

Hi Karan,

I looked a bit at your code; I don’t see where you want to connect the minimum voltage control. In what way have your attempts been in vain? I’d like to help you develop your code and help you navigate errors or other problems. Unfortunately, it’s not clear what you are trying to do and the difficulties that you are encountering.

[karan_maverick]

Dear Matt

Hello. I am trying to connect the minimum voltage input to the for loop, just like the maximum voltage has been connected.

I have attached the snap shot my code's block diagram and the desired ouput V-I loop.

Regards

Karan