TB6600 4 axis board - GPIO input?

[kjames23]

Hi all,

I have an old mini mill that I'm trying to resurrect after several years of it just sitting in the corner of the workshop. Back when it was working, it was running off an old PC with LinuxCNC and a parallel port connection to a 4-axis TB6560 board. pretty much all that stuff is broken now, so I'm rebuilding the control side from scratch. I'm using a Raspberry Pi 4B and a 4 axis TB6600 board (pictured here) that has sat on a shelf for a couple of years (I planned this rebuild back then, but got sidetracked..)

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According to the documentation i should be able to connect to it on the GPIO pins and control it from there, rather than using the DB25 port. This is good, because the Pi doesn't have a printer port! However, I can't get it to do anything. I'm using a bunch of AND gates to take the 3.3v output from the Pi pins and up it to 5v to go into the controller board. I've checked with a multimeter that I'm getting 5v at the GPIO pin, but it still doesn't seem to do anything.

Does anyone have any experience with these boards? I'm attaching the instruction PDF here as well in case that explains anything. Enthusiastic amateur here, so it's entirely possible I've missed something obvious. I remember from the old setup that when the controller was 'enabled' the steppers would buzz and now when I have 5v at pin 14 (ENABLE_ALL) nothing is happening.

Thanks,
Kev.

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[Doddy]

Are the motors energised? - can you rotate them by hand with power off, and with power on - start at the basics.

[Kitwn]

I assume you are still using LinuxCNC. I don't know how configuring this software works on the Pi but check that the pin mapping for the GPIO pins on the Pi matches the controller.

[kjames23]

Thanks @Kitwn, good point but I have checked using some LEDs and I can confirm that the pins are wired correctly (according to the controller board documentation..)

[Kitwn]

Pity. That would have been an easy one to fix!

[kjames23]

Are the motors energised? - can you rotate them by hand with power off, and with power on - start at the basics.

So, the answer is yes I could, so thanks for taking me right back there!
After a bunch more messing around, including checking with an old printer cable and hooking up some prototyping wires, I discovered:
a) It works through the LPT port
b) It then worked with the GPIO port
c) When I unplugged the printer cable it stopped working.

I can still turn the motors when they're energised, but they are more 'clunky' than when not energised and a bit harder to turn.

After even more messing around, I discovered that if you ground the appropriate LPT port pins to the same ground as the Pi, then the GPIO pins work!

I have a bunch more to fix, but it's mostly software related so I'm off over to the LinuxCNC forum. I just wanted to post this here in case anyone else has the same board, and thank everyone for their help!

Cheers,
Kev.

[Kitwn]

Who'd have though it! All this complex digital electronics and the current STILL insists you have a complete circuit before it will do anything usefull for you :encouragement:

[kjames23]

Who'd have though it! All this complex digital electronics and the current STILL insists you have a complete circuit before it will do anything usefull for you :encouragement:
I did wonder why there wasn't a GND on the GPIO interface but I just assumed they knew something I didn't... ;)

[Kitwn]

I did wonder why there wasn't a GND on the GPIO interface but I just assumed they knew something I didn't... ;)

You should always trust your own intelligence whilst acknowledging your own fallibility.

Kit

WOW! I think I'll bake that into a fortune cookie.