2182A Reading Measurements Fast Query

[gelmand]

Hello,

I am measuring V with a 2182A delta mode by sourcing I with 2400 with GPIB-USB into LabVIEW11. I am using the Keithley example given 2182Delta_LV6.vi. My goal is to understand and figure out how to measure a given number of times between each trigger. The trigger switches the polarity of the sourcemeter, and I want to know and configure how much sampling is taken place between each trigger. I will then want to manipulate this data.. averages etc...

Is this done through:
:SENS:VOLT:NPLC <n>
:SENS:VOLT:APER <n>?

If so, what is the difference? Essentially, where is my sampling rate?

Danny

[Dale C]

The overall sampling rate is determined by the source speed of the 2400 and measurement speed of the 2182A.
With out a digital filter the Model 2182A takes essentially one reading per trigger.
And one reading is determined by the NPLC setting.
Setting the NPLC to 1PLC will take the reading at about a 50Hz rate. This is slower than the 1PLC rate or 1/60 because that is only the integration rate not the entire A/D conversion.
So this is the measurement rate. You also have to consider the SourceMeter rate.
Same thing here. NPLC is for measurement and we do not use the measurement of the Sourcemeter but it still affects the overall rate.

[gelmand]

Hey Dale,

Thanks for clearing it up for me, I read up on digital filtering and I am going to try and implement it.

I have an issue though. When declaring the NPCL for 2182A the manual says to keep it at 1 or 5 for Delta mode. I was playing around and put it to 0.1 and it is working just fine, but when I put it back to 1 or 5 I am getting an Error -410. But when I run it slowly with "Highlight Execution", the lightbulb in LabVIEW it works just fine with 1 or 5 NPCL.

What is the reason for this and how can I fix it? Thanks

Also I am confused by your line

Setting the NPLC to 1PLC will take the reading at about a 50Hz rate. This is slower than the 1PLC rate or 1/60 because that is only the integration rate not the entire A/D conversion.

Can you clear that up? I dont understand when you say "This is slower than the 1PLC rate or 1/60"

Thanks a lot,
Danny