Forums
Bruker Media
Community Media
Bruker AFM Probes
SPM Digest
Application Notes
NanoTheater
Website
中文
Brochures & Datasheets
Publications
Probes Catalog
Events
Manuals & Documentation
Presentations
Guide to AFM Modes
News
Journal Club
Webinars & Video
Nanovations
Other
Hello-
I'm sure you get this all the time. I, like many an AFMer worldwide, would LOVE to use an external DAC/ADC to acquire the deflection signal and drive the Z piezo up and down on a Nanoscope IIIa. Getting the deflection is trivial, but inserting a LV Z, now that's a-whole-nother issue many have struggled with. So, after perusing the Z board of the controller, I found the op-amp which produces the LV Z signal prior to HV amplification (+-12V). Is it possible to inject my external drive voltage here? Two thoughts came to mind: 1) Set the op-amp output to zero volts in software (using zero start dist and zero scan dist) and simply connect my external low voltage input here. Or, 2) Just unseat that op amp and insert my voltage in the OUT pin of the op amp holder? You guys are great. Many thanks.
-Ray
There might be a way to do it with Zmod, but I don’t think so. I will ask around here.Your first idea is risky since the output of the LV would still be connected. I think it would become a battle of the controller vs. your electronics to control the LV value. If you really want to do this you should cut the trace. . .however this entire path is fraught with peril and I cannot recommend it.If you are going to unseat the op-amp, it won’t be amplifying anything, so I would just use the SAM (there is a switch that allows the signal from the controller to be interrupted and allows the user to inject their own HV signal). Good luck,Steve
Thanks for the quick response Stephen-
After thinking about it I realized the first idea can't work.
BTW, I meant to unseat the OP27 op-amp that produces the LV Z not the HV op-amp. I believe this would leave all other relevant connections intact, and I would simply insert my LV signal in the holder at the output pin to emulate the LV op-amp. I'll probably give it a try on an older machine. Thanks again.
Steve,
Z-Mod would not give you enough gain as the signal is attenuated IIRC. If it would be my controller I would probably just convert that OP to a summing amp which is simple enough. Then the output would become Vout = -(Vnanoscope + Vexternal) in the case the input resistors are of the same value.
Stefan
Stefan, that sounds like an ideal solution, thanks. This way I can disconnect my external signal, or simply ground it, and still use the Nanoscope controller regularly. I'll give that a shot.