Picomotor driver scope traces

I previously posted about getting the picomotor up and running. Picomotors are awesome little motors which provide 30 to 100 nanometer resolution without gearing. Anyway, I cleverly almost blew it up the driver other day,  by sticking 15 volts into the 5v line. A repair would be tractable, as it’s all discrete 1980s logic, however luckily all I need to do is change one of its many fuses.

Anyway, I really don’t ever want to by another driver, as it was too expensive for a bunch of 74 series logic and some big inductors. So I figured I’d grab some waveforms just in case I ever decide to build one. The waveforms however are somewhat confusing… my understanding is that when moving in one direction I should see a sort pulse, followed by a long pulse. In the other direction a long followed by a short. That’s not really what I saw. The baseline appeared to shift between forward and reverse motion. And it didn’t look like the pulses changed order… I may revisit this in the future and grab some more traces. But the useful information is that the driver uses 150v to drive the stack, short pulse width is ~20us, long ~100us. Maybe…

[UPDATE: I think my non-sleep deprived brain understands these traces a little better basically we’re interested in the rise and fall time, not the durations of the traces. So I think these traces make sense, in the first set we have a fast rise time and a slow fall, the second fast fall, slow rise. The fact that the baseline I don’t think matters too much, though there’s probably a reason for this that I don’t yet fully understand]