I need a labview program for measuring voltages from four quadrants of a quadrant photodiode simultaneosly.I 'am using a multimeter with GPIB KUSB488A

[perumpadapu]

I'am from BITS pilani a research institute in india.i 'am doing some instrumentation.So  I need to measure voltage sfrom the four quadrants of a  quadrant photodiode simultaneosly.I'am using keithly multimter for DC voltage measure ment with GPIB KUSB488A.I expect a reply

[johnsold]

What kind of reply do you expect?  You did not ask any specific questions.  Better questions get better answers.

If you want to hire someone to write a program for you, you should post your request in the Jobs Board.

If you want help learning how to do it yourself, please tell us what you have tried, what about it does not work, and ask specific questions.  We do not have your instruments or data sources, so you would need to provide some typical data for us to work with.

Most multimeters can only make one measurement at a time, so how do you propose to get four simultaneous measurements?

How fast do the measurements need to be? What are you doing with the data after you get the measurements?

Lynn

[Albert.Geven]

Anyway its is a good reply.

four simultaneous measurements you need always four meters, maybe in one package, but you need four.

[perumpadapu]

Yes my multimeter have four ports .So i can read four voltages at a time. I need the program done.I t should be very fast as soon as light falls on the quadrant photodiode. 

[johnsold]

You have not said whether you want to hire someone to write your program.  As I pointed out in my previous post, you need to do your part.

Very fast is not useful. Please specify a number: x readings per second per channel.

Also specify the model of the multimeter you will be using.

Lynn

[perumpadapu]

yes I need to hire someone to write the program .The data should be 1ooo signals per second.The model number of multimeter  is keithly 2000 multimeter.I expect you will help me.Any thing you want more.

[Albert.Geven]

Hi

A keithley2000 is a multimeter that can sample one channel at a time.

I've seen them since several years and they got faster but surely they cannot deliver 100 measurements/sec for more than 2 seconds.

Furthermore a k2000 cannot do simultaneous measurements at all only serialized measurements. So it is not suited for what you need.

[johnsold]

The best way to hire someone to write your program is to post a notice on the LabVIEW Job Openings Board.

You should have a clear statement of the work to be done, including the technical requirements and the time frame in which the work should be completed.

As Albert stated you will not be able to get 1000 readings per second.  While the multimeter can convert that fast in 4 1/2 or 5 1/2 digit modes, the scanner cannot switch that fast.  The data sheet does not specify how fast the data can ge transfered via GPIB, but some of the data suggests that this may slow things down also.  For RS-232 it specifies 55 readings per second.  I did not see a specification on settling time, which may also be a factor when switching channels. I would guess that about 5-10 readings per second for four channels would be about what you could accomplish with that instrument.  The readings on any channel would be at least 25 milliseconds after thre reading from the previous channel.

Lynn