Increasing the scan rate for Keithley 2700 f AC Voltage measurement

[cstorey]

Did you have any luck with this?  I pulled out the manaul for my 2750 today and read through the AC voltage measurement section.  A few interesting tidbits in there:

1) NPLC has no effect on AC measurements unless rate is set to FAST.  (>300Hz)

2) There are 3 AC voltage rate and bandwidth setting and one take 1.2s/measurement.

3) You can use the SCPI command "SENSe:VOLTage:AC:DETector:BANDwidth <NRF>

Manual sections 4-9 to 4-13 are important reading..

Bandwidth
There are three bandwidth settings for ACV and ACI measurements; 3 (3Hz to 300kHz),
30 (30Hz to 300kHz) and 300 (300Hz to 300kHz). To achieve the best accuracy for ACV
and ACI measurements, use the bandwidth setting that best reflects the frequency of the
input signal. For example, if the input signal is 40Hz, then a bandwidth setting of 30
should be used.
To set bandwidth, simply specify (approximately) the frequency of the input signal. The
instrument will automatically set the bandwidth as follows:
<NRf>

= 3 to 29 3Hz to 300kHz
= 30 to 299 30Hz to 300kHz
= 300 to 300e3 300Hz to 300kHz

Example #1 — The following command sequence sets ACV rate to 5 PLC. In order to set
rate for an AC function, bandwidth must first be set to 300:

VOLT:AC:DET:BAND 300 >>>> Set ACV bandwidth to 300.
VOLT:AC:NPLC 5 >>>> Set ACV rate to 5 PLC.

You can easily make this into your own VI..

And try to make a better example for "Performance.vi" Example for AC voltage measurements like attached.

Test it and let me know if that works.  (I don't have 7700 card, only 7712s.)

Craig

[oap3952]

Sorry for the delayed reply. I was able to work on the performance.vi

I agree to your answer. The bandwidth adjustment is added before we could set our measurement to lower NPLC or Aperture Timing.

I used "ConfigAC.vi" before "timing.vi" in "performance.vi" . I set the bandwidth to 30000 and the measurement is faster now.

Thanks for all your help.