HI - 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. 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.). Marty >Hi Geoff, > >This has come up a couple of times over the years for plain old CellQuest, >and I had a quick look through a couple of files when Chris groves asked in >May 1998, and I asked at the time if anyone from B-D would cast any light on >it - if they have, they haven't shone it in my direction. I don't know if >things have changed for Pro, or if these things are valid for sorters >(presumably they won't hold for machines with more than 5 PMTs), but this is >what I gleaned (and Chris confirmed) back then: > >> BD$WORDS 14-18 cover PMT volts for ssc to FL3, BD$WORD 13 looks like it >> might encode FSC gross gain (E00,E01,E02,E03,E-1 being covered by 0 to 4). >> >> BD$WORDs 18-22 have 100 times the incremental linear gain (eg 5.57 maps to >> 557). >> >> 23-27 seem to indicate log/lin amplification (1 for lin, 0 for log). >> >> 29 to 33 seem to cover the trigger thresholds for parameters 1 to 5. I >> haven't got a compensated sample so I can't help you out on that front, but >> my guess is that it would be held in words 34 to 37 (as 10 times the value) >> presuming that there are four potential compensations in the file I've got. > > >I haven't revisited this stuff since 1998, but will do next week and see how >it works for the Calibur that I have. > >If you'd send me a couple of files acquired with different settings from the >same machine, along with a print-out of the settings in use at the time, I'd >be happy to pick through them and tell you what I come up with. > >Chris told Alice Givan of DropPrint when she asked a similar question in >September 1999, the link that Alice gave on Eric Martz's site appears to >have died, but a big up to Purdue for pulling together all things flow >cytometric : > >http://www.cyto.purdue.edu/flowcyt/software/Catalog.htm#dropprint > >It crashed when I tried it out just now, which doesn't mean much, except I >can't tell you what it produces, so you might want to try it out yourself. > >Cheers, > >Ray > >ps Maciej, you can use this to your web page if you'd like. -- Marty Bigos Director, Flow Core 415-695-3832 Gladstone Institute of Virology and Immunology Building 3 SFGH
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