Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Zero Cool on April 10, 2011, 11:05:07 AM
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Is there a limit as to how many parallel port cards can be used with Mach3??
I am currently running 2 in the machine I am building. the first card is pretty much used up controlling the TB6550 controller board. it seems to require Step, Dir & enable pins for all 3 axis plus spindle control and there are no pins left.
I added a second card to control some Solid state relays for Vacuum and flood pump and I am using the rest of the pins for manual direction control.
But I would like to add a 3rd card so I can utilize the P.I.D function for spindle speed control. I just don't have anymore available inputs on the 2 existing cards.
So I'm curious if I can run 3 cards with Mach3. assuming I can get 3 cards to run in the PC in the first place.
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Two parallel ports is the max as far as I am aware.
Hood
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that's a bummer with only 10 input pins. I need one more! or i need to re-think how to do the jog buttons.
I currently have:
X Limit
Y Limit
Z Limit
E stop
Jog X+
Jog X-
Jog Y+
Jog Y-
Jog Z+
Jog Z-
and that wipes out all 10 pins. I need a way to get a speed pulse into Mach3 any suggestions??
I suppose I could disassemble a USB keyboard, remove the keyboard PCB and wire the arrow keys to the direction buttons on the panel. that would free up 6 input pins. but i really don't want to do that if i don't have to.
Plus I would like to be able to add a digitizer at some point and that will require yet more pins....hmmm
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you could wire the x, y, and z limit switches in series and run them into one input, which will give you two inputs free.
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I was wondering if i could do that or if there was a reason it needed all 3?? sweet well there are the 2 pins i need then!
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Other thing to look at is something like the PoKeys, it will give you approx 55 I/O if I remember right. Time critical things such as home switches and step/dir will need to be on the port but things like external switches the Pokeys will handle very well.
Hood
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You can probably use a jumper to enable your drives, and not have to use the paralel port, which free up 3 pins. Are you using a breakout board that allows pins 2-9 as inputs on the second port? That may help.
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I have 2x 25 pin breakout boards in my custom motor controller box. I have access to all 25 pins on the BOB, there is a cable that connects from the BOB to the circuit board. so yes I have access to all pins. So can i jumper the enable lines to +5v? or should I jumper the three axis together to one PC port enable pin?
I am using a HY-TB4DV-M Toshiba TB6560 motor controller board commonly found on eBay.
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If its any help I have taken all enable lines through toggle switches (mounted on the controller case) to +5 volts and this allows an axis to be disconnected if required for any purpose.
Tweakie.
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sweet. ok I am reworking how I am going to do this then. Thanks!
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Ok a little clarification. the enable lines. that simply turns on/off an axis? is there any reason why these lines shouldn't just be tied directly to +5v? why would you want to shut off 1 or all axis? without shutting off the whole controller?
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No reason why you cant just take them all to +5 Volts.
There are some occasions when I wish to disable just one axis.
When working on long jobs (longer than the working table) I produce the artwork in one piece and with a pause in the GCode at the appropriate point I disable the Y axis, release the work (which remains in the same place) whilst the table is moved by hand to the new location. The work is re-clamped, the axis enabled and the job restarted. I have tried various other methods and this system works best for me when making long signs.
When I use the laser head, the Z axis carries the focus lens assembly and once set remains the same for the entire job. I use standard engraving GCode and therefore any Z commands will alter the focus so disabling just the Z axis prevents this.
There are other occasions but it is one of those things that once you have it then you find the uses for it. ;D
Tweakie.