Unable to send arbitrary signal to Dc power supply. Help. Please.

[DanRen_IQA · Accepted solution]

I believe that you have a misunderstanding of the purpose of the analog inputs to this power supply. It does not have a gain of 4. The power supply is limited to 20 V output maximum. The analog input is not a signal that is amplified by the supply, but rather is summed with the programmed DC voltage on the output. If you'll see in the manual for this supply, it states "The effect of the analog programming source is always summed with the values programmed over the GPIB or from the front panel." So if you program 10 V over the GPIB and apply -5 V to the analog input, the resulting output voltage will be the sum of 10 V and -5 V, or 5 V. Futher, your table is asking for changes in the output voltage at a much faster rate than the GPIB programming and power supply can sustain. Your first requested delta is 1.066 ms. The power supply specifications clearly state that "Command processing time: Average time required for the output voltage to begin to change following receipt of digital data is 20 ms for the power supplies connected directly to the GPIB." So you need a minimum of 20 ms for the supply to process each GPIB command. Bottom line is that I don't think that this power supply can give you the kind of output you expect.

Also, judging by the way your table values increment, I think you expect to delay each iteration of the loop by the delta t from entry to entry. However, the way your code is wired, each subsequent iteration of the loop is going to take a longer time than the previous loop. In the first iteration, you ask the Wait (ms) routine to wait 0.00 ms. Next iteration asks for 1.066 (rounded to 1) ms. Next iteration, 2.257 (rounded to 2) ms, etc., with each iteration getting longer. You either need to program your table with delta t's, or add code to perform the delta t calculation.

You might look into a power supply like the Keysight N6705B, and N6751A module, that allows programming of up to 512 arbitrary waveform points, and can adjust the output of the power supply at a much faster rate than you'll be able to get with your present supply. 

Good luck.

[Blokk · Accepted solution]

 I gave a wrong minimum time delay value in my prev post, yes it is 20 msec, not 50 msec. but still, I would NOT go below 100 msec between voltage changes, just to "play safe"...

So if you wanna use my VI, use a 2D array like this below, create the DELTA time values in msec and put them into the array, I only made the first 3 values for you, you can make the rest yourself...:

[Blokk]

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@DanRen_IQA wrote:
Also, judging by the way your table values increment, I think you expect to delay each iteration of the loop by the delta t from entry to entry. However, the way your code is wired, each subsequent iteration of the loop is going to take a longer time than the previous loop.

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I think you did not read the whole story 🙂 I gave the VI to the OP, but he tried to use it in a wrong way...

[Dennis_Knutson]

I've told the op that there is no amplification a couple of times and he has ignored that. I don't know any he does not read the manual and understand. Perhaps a manual exists in his native language.

[James.M]

 I agree, a manual in his native language might help. Unfortunately, the only link from the site is to an english one and I can't find any other documenta...

[Dennis_Knutson]

Jeet,

Since you do not understand the instrument, I would recommend you seek the help of a fellow student or perhaps a grad student. One that better understands English and an electronics type that understands basic instruments. A couple hours of personal help will go a long way in overcoming these basic stumbling blocks.

[jeet.saha3.js]

Hello people.

My problem has been solved. Thank You so much everybody for bearing with me and keeping patience with my stupid questions. Everyone here has helped me a lot and I heartily appreciate everyone's help. 


Thank You so much. 

I will remember this help. 

[Blokk]

If your problem has been solved, you should mark that post as a solution, whichever helped you. You can even mark more than one as a solution. This way you can help others in the future who are dealing with similar hardware/problem.