[GreenKeys] [External] Re: Interesting Punch on eBay

[Jones, Douglas W]

From: W2HX [w2hx at w2hx.com] -- Friday, March 24, 2023 12:11 PM

> Can it be told from the listing if it is 5 or 8 level (or in between)?

I'm guessing 8-level because the two magnet windings visible in the window are very close to the glass.  Those are the ones they left out in the 6-level versions.  Also the coarse windings visible on thee magnets suggests that they're the 48V version.

> Also, I’ve read it can operate at different speeds. Does this require a change in gears or is it just done electrically (like sending the data more slowly)?

It requires a change of timing belt and sprockets to change the speed.  The controller for each speed  needs to shape its drive pulses accordingly, and you also need to adjust the timing angle of the feedback clock pulse (akin to fooling with the range finder on a serial TTY).

> My understanding is this is a parallel device. Anyone ever design an interface for it?

The manual for the BRPE tells you all you need to know to design the controller (pulse lengths, voltages, etc).  I have an old interface for a PDP-8 that was designed for a BRPE, but then someone modified it.  I'd like to put it back to its original design to control one of my BRPEs, but I have no schematic.  It would be interesting to reverse engineer the controller, which is entirely made with R and S series Flip Chip logic (that's to say, discrete transistor logic with +10 and -15 supply voltages).

           Doug Jones
           jones at cs.uiowa.edu
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