[Sem] Scrapping Super IIIA

[Jeff Miller]

Ooops, I read you last message first. I see now you have the same speculative designs on the column as I would have. 
I've largely done the work of building a  high performance digital controller that should be widely applicable to most SEM columns. 
Although I might do it differently today using a high speed ADC/DAC board from NI, at the time NI's best solutions were out of reach. Instead I used a high-performance  16 bit parallel NI video capture card and designed an outboard ADC/DAC unit to to feed the card based on a $25 Silicon Design evaluation board. 

Beta tests indicated the design worked flawlessly.
Since that time, the $25 development kit from Silicon Designs seems to have rose to $99, It may not be available any longer. As for the hi-speed video card, not sure it is a current product. Market price may be low as "obsolete", or may have skyrocketed as a crucial and hard to find spare for dedicated applications. 

But worse, I can't seem to find the computer with my all-important glue software on it. I think an over-zealous housemate may have tossed the computer "for my own good" as just another piece of "useless junk" I "clearly" did not need, and was confident i would thank him later. Grrr: that fool cost me at least $3000 in patronizing me that way across several pieces of equipment.
I may well find it. I think i still have the NI card and SD evaluation board front end, breadboarded with support components. 
I should be able to compose a reasonable block diagram and detail my approach to designing the software, if i can't find the software. Because timings were critical, the code I wrote was in assembly language. Not likely more than 100 lines of assembly code, it nonetheless required at least one month of intense coding.
In any case it may be worthwhile to compare approaches.
-Jeff
      From: John McMaster <johndmcmaster at gmail.com>
 To: "sem at lists.noisebridge.net" <sem at lists.noisebridge.net> 
 Sent: Thursday, June 4, 2015 9:00 AM
 Subject: [Sem] Scrapping Super IIIA
   
Due to vacuum leak problems etc that I'm tired of troubleshooting, I'm 
going to scrap my Super IIIA and get something more modern / more plug 
and play.  Before I do, does anyone have interest in it? Haven't decided 
if I'd want some money or it would be free.

If I do scrap it, most likely what that means is I will e-waste recycle 
all of the electronics and keep the column / vacuum system for the pipe 
dream that some day I will fix the leaks and design my own control 
system for it.  (this part is a mere fraction of the entire system size)

Note: I'm keeping the small ISI SEM (M7) so will not be disposing of my 
extra filaments, etc

John

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