[allaces]

Dumb question for the DB25 connector as follows:

Mu understanding is the STEP/DIR PINS for 6 axis are 1-12 .
Isn't that a conflicting problem for the INPUT and OUTPUT PINS if the 6 axis pins were all used?

STEP/DIR PINS = 1-12
INPUT PINS = 10-13,15
OUTPUT PINS = 2-9,1,14,16,17

[ger21]

It depends on the specific breakout board you'd be using, but yes, 10,11, and 12 are inputs, and won't work for an axis.
If you are going to need 6 motors, you'd usually use 2 ports.

[john-100]

using a PC parallel printerport or motion controller emulating a printerport ( ethernet smooth stepper for example )

you have 12 outputs that you can use as use as 6 step signals and 6 direction signals

the only output pins are pins 1 to 9 + pin 14 + pins 16 & 17


you have only 5 pins to use as inputs pins 10 to 13 plus pin 15

pins 18 to 25 are connected to ground

Attachment 408210
note the printer port has 3 data latches at Hexadecimal addresses 378h , 379h & 37A

with a 6 axis machine your going to need a second printerport to provide the extra I/O

to control other things like the spindle , coolant pump and live tooling for instance


John

[109jb]

You can still use 6 axes on a single parallel port. Atypical parallel port has 12 outputs and 5 inputs. The 12 outputs would be taken by the dir and step for the 6 axes, but for the inputs you can combine things like limit switches and homing switches to retain more inputs. For example all of the limit switches can be wired together and only use one input. Also, the limit switches can do double duty as homing switches so you could essentially get all limit and home switching on a single input. You would have to home one axis at a time, and if a limit were tripped, the controller wouldn't be able to tell you which switch tripped, but on many machines this is not a problem any way as the axis exceeding the limit will be obvious. That would leave 4 inputs for other stuff like a tool setter, or a probe, or whatever.

The drawback to the above is that you wouldn't have a separate enable pin to enable/disable the motor drives, but you could use a mechanical switch for that if needed.

BTW it is unclear if you are thinking pins 1-12 are for step/dir, but they are not. As said there are 12 output pins and they are what you listed 1-9, 14, 16, 17. You would assign those to the step and direction signals for the motor drives.

[allaces]

It's been a long time since I posted on this forum and I'm glad I did.
Thanks to you all for your input.
This is definitely the place to get good advise and information!

109jb

I did state pins 1-12 and that's where I was confused. With your very good and simple explanation... I can now see that I can use "any" of the 1-9, 14, 16, 17 output pins to control motors, etc...

I'm completing a build for a 24 X 48 CNC router and a 6 Tool ISO20 ATC that I designed and built. The ISO20 ATC unit is "Stand Alone" and driven buy a Chinese 2.2KW spindle VIA custom threaded coupling nut. I'm using 4 Nema 34 motors (2 for X axis).

The Chinese VFD will be controlled by USB-SERIAL CH340 to overcome the Chinese VFD MODUS shortcomings.

Even without the VFD, I still need 11 outputs pins from 1 port:

Outputs: 11 out of 12

(8) for the Stepper Motors alone.
(1) for Rack extend
(1) for PDB (M7)
(1) for Air Blast

Inputs: 4 out of 5

(1) Extend Rack for sensor verify
(1) Retract Rack for sensor verify
(1) PDB Clamp for sensor verify
(1) Limit/Homing switches

Did I miss anything?
Any comments or advise is VERY welcome!

Thanks,
Ray

[ger21]

Home and limit switches, estop.

What software do you plan on using?
These days, few people are still using parallel ports, instead opting for controllers with much more I/O, that are relatively inexpensive.

[allaces]

Home and limit switches, estop.

What software do you plan on using?
These days, few people are still using parallel ports, instead opting for controllers with much more I/O, that are relatively inexpensive.

Using one input pin dedicated to all the limit/home switches (looped together) and my USB Pendant has the E-Stop built in.

Mach3 is what I'm using on all my home/hobby CNCs which I previously converted and some built from scratch. Mach3 is very affordable and so far... "does all the things I want it to do", even though it now seems I'm reaching the limits.

I've been a machinist for most of my life and I ran a CNC shop before retiring. I would not have used Mach3 in that environment, but I personally think it's still a great choice for the "home/hobby" machinists like me who still love the trade.

I like the idea of a CNC Router with an ATC. Hopefully I can get it to work well using Mach3. If not... then I'll upgrade whatever needs to be accordingly.

I know there is no lack of affordable alternatives out there... but this is something I'd like to try and a great pastime for me.