Download Tektronix 2430A Graphed:

Tektronix 2430A Graphed
Features of the Labview VI:
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Chose Display of Ch1; Ch2; DUAL; XY
Specify Channel 1 parameters - Ch1 v/dev, Ch1 offset
Specify coupling for Channel 1
Specify Channel 2 parameters - Ch2 v/dev , Ch2 offset
Specify coupling for Channel 2
Specify the time of first sample (X0).
Specify A and B sec/div
Specify trigger parameters - slope, level mode, source.
View the waveform.
Save the waveforms in ASCII file
The front Panel of the program is shown below:
Functional Details: All the parameters passed at the top level of the VI are passed to Tek
2430A.vi which processes them in sequential order as follows:
1.
Send Channel Parameters: All the parameters passed through the controls are passed
to 2430 Channel.vi. Along with these acquire mode is also passed to this VI. 2430A
supports following acquire modes:
a) Normal
b) Average
c) Continuous Envelope
d) Envelope
The acquire mode is passed to 2430 Channel.vi using a constant function and is set to ‘0’
by default. This can be changed using Edit tool. The Block diagram of this step is shown
below:
Details of 2430 Channel.vi: The Functions of this VI are:
a) Generate Ch1 & Ch2 Command String: Here we add coupling information
using Pick Line control, voltage/Div information by using Threshold 1-D
Array function and Y-Axis position (using format string) to the command
string passed through the GPIB interface. In case offset is specified, it also
properly set using Index array and min-max controls.
b) Send Command String to 2430A Digital Oscilloscope: The command string with
proper arguments is sent through the GPIB interface to digital Oscilloscope. The block
diagram is shown below:
2.
Send trigger parameters: In this step acquire time is calculated and further this
information along with the other parameters are passed to the Digital Oscilloscope.
The two VI’s instantiated in this step are:
a) 2430 Acq Time: This VI takes in inputs as A and B Sec/Div and time of first
sample(X0), and processes these parameters to valid GPIB settings for the
instrument and final delay time and X0 are calculated which can be sent as
trigger to the GPIB instrument. The Block diagram of this VI can be viewed
in Appendix Fig1.
b) 2430 Trigger: This is used to send the final trigger commands to the GPIB
instrument. This is achieved in three steps:
(i) A Trigger Parameters: THe command string generated for triggering
channel A based on the user inputs is finally sent through GPIB
interface to 2430 A digital Oscilloscope.
(ii) B Trigger Parameters: THe command string generated for triggering
channel B based on the user inputs is finally sent through GPIB
interface to 2430 A digital Oscilloscope.
Note: All the supported functionality – To specify coupling, to specify source,
to specify pre-trigger points etc is available through the VI. A few things
have been hardcoded to some default values but can be easily made
controlled and can then can be specified by the user.
(iii) Send Delay MODE & PARAMS: The delay mode specified by the
user and processed in Labview for the instrument is finally passed to
the GPIB instrument. All the possibilities have been documented on
the VI itself.
The Block diagram of all these VI’s can be viewed in Appendix Fig2Fig4.
The VI used to call these low level VI’s is shown below:
3.
READ WAVEFORM: Finally after all the channels on the Digital Oscilloscope has
been triggered, the waveforms are read from the instrument based on the selection
done by the user. The wave form is read from the instrument using Readwfm.vi
whose details are available as a separate document. The various options available are:
a) Channel1(Ch1): If we need to read channel 1 only.
b) Channel2(Ch2): If we need to read channel 2 only.
c) DUAL: if we need to read both the channels and wish to reproduce both the
waveforms at the same time. This steps is achieved by first reading channel1
and then reading channel using sequential loop.
d) XY Mode:
All the waveforms read from the 2430A digital oscilloscope can be saved in ASCII file.
Based on the option chosen - the program will pop-up dialog boxes for file names where
the ASCII files needs to be saved.
The VI for this step is shown below: