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WRXi-OM-E Rev B
Note that in VBS, after you have corrected an error and clicked on "Apply," the error message may go on flashing
for a few seconds, or a few acquisitions, before being erased. Look for the "Script OK" message. Be patient
before assuming that you still have a bug.
If your calculation requires data to be used at some other horizontal positions than their original ones, make sure
that your algorithm does not try to send data to non-existent array positions, that is, beyond the edges of the
screen. You may have to truncate your output trace, as happens with the instrument's Enhanced Resolution and
Boxcar functions.
No output will emerge from a script until you press Apply.
No output will emerge from a script until it has received an input. This includes the case where the input data are
not used in calculating the output data. So you must have had at least one acquisition before you see anything.
Because you can introduce undeclared variables at any point in a calculation, VBS does not check your spelling.
You can make a portion of a trace disappear if you set the values to 32767 or -32768.
You can highlight a section of a trace by making the points alternately too high and too low by a suitable amount.
Providing the memory length is not too short, the compaction algorithm will give the effect of a thicker trace.
The lengths of the output trace and the input trace need not be the same. You can even make the output trace
longer than the input trace, but you will need to unzoom it to see it all. This feature can be used to avoid
compaction problems with non-linear horizontal scales. It can also be used to show several versions of a function
at the same time, without having to set up a separate script for each one.
If your program structure is complicated, consider typing all the IFs, ELSEIFs, ENDIFs, FORs, NEXTs, etc and
then clicking Apply. You wont get any output, but the system will tell you if the structure is acceptable. Then you
can insert the actual program statements.
Always try to make the script as independent as possible of variables such as V/Div, T/Div, and memory length,
unless that would make it harder to understand. If so, give some values as examples, and explain how the script
would have to change if the variables changed.
Errors
The instrument VBS tries hard to help you when errors occur.
Errors may be of two main types:
1. The script may not be usable because the interpreter cannot construct a logical structure from it.
2. The script may be usable, but may fail while running because an incomputable function has been requested.
Sometimes the line number given for an error is wrong. This can happen when the error is of this general
type:
1. Missing "Next" Missing "End If"
2. Extra "Next" Missing "Until" etc.
This happens because VBS cannot know where you should have put the statement.
If at some point during the calculation of an output array, a value goes outside the allowed range, the calculation
will stop, and you will see the new values up to the point of the stoppage. To the right of that point, the trace will
display the previous values. In fact, if you deliberately recalculate only a part of a trace, you can have a mixture of
new and old values.
