settings for dmm sfp

[Jeremy@hill]

I am using the DMM SFP for the pxi 4070 DMM.  I am having a problem duplicating the speed and accuracy produced by the SFP versus what I am actually programming up.  I am using Delphi to program through a wrapper file to the DMM dll.  I need to know how to duplicate the settings on the SFP.  Here is what I am doing...

V~ selected...

Range set for 50V...

Resolution set for 6.5...

Min Freq. set for 440 hz...

Power Line set for 60 hz...

Scaling NOT selected...

Calculation set for None...

AutoZero NOT selected...

Offset Comp. Ohms NOT selected...

Min/Max IS selected...

Null Offset NOT selected...

Filter NOT selected...

I am basically using the C calls how could I set this up in C.

note: I am watching the MAX to make my calculation.

[wildcat_600]

Hello Jeremy,

I see you are performing an AC Voltage measurement with the SFP.  But what speed and accuracy problems are you encountering?  I am going to assume that your SFP is returning measurements faster than your Delphi code.  If speed is an issue it may be that you need to set the Minimum Frequency in your code because the bandwidth affects the speed.  If accuracy is an issue then you will want to make sure that the measurement is setup correctly in your code and has all of the same settings as the SFP. 

As you might know Delphi is not officially supported to use the niDMM driver.  This is why you have to use the wrapper file to get some of the functionality of the driver in Delphi.  Many customers have successfully been able to use the DMM Mode of the DMM to take measurements.  I just wanted to mention this because every function in the driver is not guaranteed to work with the wrapper file.

Please let me know what exact problems you are experiencing and I will do my best to help you.

Have a great day,

Brian P.
Applications Engineer
National Instruments