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« on: February 03, 2016, 02:31:12 PM »
Hi, I'm back and I've tried a couple of things as we discussed above:
1. Connected 12VDC to the external power supply terminals. This works. When I short GND and one of the switch terminals, the LEDs on the diagnostic tab react accordingly, But I'm afraid this is the only option that works, and it's not usable as is for what I wanted to do. Next thing is to try to trick the BOB, so it would work with 5VDC instead of 12VDC. The switch pins are connected to the opto couplers via the 1K resistors. I don't know if tweaking their values would help or not, maybe I'll try tomorrow, as I can't do it at home, too tiny for me;)
2. Next I connected USB cable, but this does't affect the outputs as 12V does. It seems to me it works exactly as when connected to the PC power supply. No changes on te diagnostic tab...
3, And now something I don't understand at all - if no power is connected (not 12VDC, nor USB or 5VDC from PC), I can still jog via keyboard and run the code...
This is a great BOB. Not only can it use wide range of voltages from peripheral and local sources, it even runs without an... Now that's what I call engineering;)
I have measured voltage on the driver terminals, and it is 1.9V. My guess (not that it's worth much) is that BOB gets it from the LPT port and that this is somehow enough, as when I unplyg teh LPT cable, there's no voltage on outputs.
Now my question is, even if I could use that ext. power connection, either tweak it to work with 5V or, theoretically, if I had 12V encoder instead of 5V one, how exactly would I connect the wheel to the BOB input terminals? I guess I can't just connect it like the switch, I would probably have to put some transistors on the switch inputs?
It seems to me it gets more and more complicated, given it already works connected directly to the LPT... But maybe it won't hurt to finish what I started anyway
Thanks,
Miso