Re: BD$WORD file header fields

From: Ray Hicks (ray.hicks@btinternet.com)
Date: Fri Oct 26 2001 - 18:26:19 EST


Hi Marty,

> As you know, many functions (but not all) on the current BD
> instruments are computer controlled. Conceptually you can think of
> each instrument as having some memory which the computer writes (and
> reads) values, and the instrument interprets. There are 64 of these
> locations. Each instrument type may have a different interpretation
> of what some of these locations mean. Some are easy to figure out,
> such as PMT voltage. Others, such as the pulse processor (or DDM)
> configuration, are more complex. I believe BD considers the full
> description to be proprietary information.

You're right, of course, unfortunately B-D seems to have chosen to put PMT
voltages, gains and compensation solely in the proprietary part of the file,
eschewing the use of standard keywords (such as $PnV and $PnG)
>
> The reason for storing these values in the data files is clear - it
> allows the user to read them (using CellQuest) to either print them
> out or return the instrument to the configuration that was used to
> collect the data (although it is unlikely one would get exactly the
> same values due to alignment changes, etc.).
>
That would be a justification for using the FCS-defined keywords as well
though wouldn't it? Without having to re-invent wheels. I'm not too sure how
much use most of the information that is stored in the proprietary parts
could be - what does it matter for analysis how many volts were used on a
particular PMT for a particular experiment? -except for QC.  But some of it
definitely is, as Mario pointed out as a result of my backfiring jibe, the
linear gain values can be useful to know.



Ray



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