Text preview for : 27xxMaxSpeedBenchMark.pdf part of Keithley 27xxMaxSpeedBenchMark Keithley 2700 27xxMaxSpeedBenchMark.pdf
Back to : 27xxMaxSpeedBenchMark.pdf | Home
Benchmarking the Reading Rate of an Integra Mainframe: Model 2700, 2701 or 2750
The DC Measurement Speeds specifications for the Integra mainframes are defined as the rate at
which data can be acquired and put into a memory buffer. In order for your application to have
this data for analysis, additional time is required to transfer the data across the bus (GPIB, RS-
232 or Ethernet).
In order to verify the speed specification, analysis of the data returned when applying a signal of
known frequency is required. If a 1 Hz waveform is applied and a buffer of data equal in size to
the maximum rate is acquired, then the data in the buffer should represent 1 second or 1 full
cycle of the applied waveform.
Below is a screen shot from a LabVIEW program that performs this benchmark. This example, in
LabVIEW 6i, is available in the download center of the Keithley web site as an example program
for the Model 2700. It uses NI-VISA to send SCPI commands to the 2700 over GPIB.
Figure 1: One Cycle of Applied Sine Wave
As the Waveform Chart shows, one complete cycle of the applied sine wave has been acquired in
the 2000 buffer points for the 2700.
If using a 2750, adjust the buffer size to 2500 samples. If using a 2701, adjust the buffer size to
3500.
Below are the SCPI commands used in the program:
*RST;*CLS; Reset the instrument; clear status and errors
TRAC:CLE Clear the buffer
INIT:CONT OFF Disables continuous initiation (auto run)
:SENSE:FUNCTION 'VOLT:DC' Measure DC volts
:FORMAT:ELEM READ; Store only the reading in the buffer
:SYSTEM:AZERO:STATE OFF Do not use auto zero
:SENSE:VOLT:DC:AVERAGE:STATE OFF Disable filters
:SENSE:VOLT:DC:NPLC 0.01 Set integration rate; 2701 has 0.002 available
:SENSE:VOLT:DC:RANGE 10 Use a fixed range
:SENSE:VOLT:DC:DIGITS 4.5 Set the reading resolution
:TRIGGER:COUNT 1 Only one trigger required
:SAMPLE:COUNT 2000 Change Sample Count according to your Model
:TRIGGER:DELAY 0.0 Do not delay after trigger is issued
:DISPLAY:ENABLE OFF Turn off the front panel display
:READ? Issue software trigger