Paralell port connection

[josh yoder]

I'm a total newbie to Cnc, and I don't know much about computers. I'm setting up a Dave Gatton machine with the xylotex 4 axis controller. I'm using the trial version of mach 3. So far,I have not been able to get any of the Steppers to run. On the diagnostics page the green lights on the "port 1 pins current state" are not illuminated. I went into the service manager - ECP printer port properties and changed "current configuration" to "basic configuration 0000" I then got a dialogue box that says "resources marked with '?' must be explicitly set". Since I didn't know what I was doing,I changed it back to "current configuration". When I clicked OK,the steppers buzzed louder for several seconds before going back to their normal hum. This is the first time I have gotten any response from my Cnc,so I think I've found my problem,but it still doesn't work. The green lights on the diagnostic page are still not illuminated. It sounds like my problem is in the computer,not mach3. Can anyone tell me what to do? Sorry for the long post, I hope I've explained clearly.

[Jeff Pollard]

Hi,

  The noise you heard was because some program in the PC momentarily accessed the parallel port changing the state of the STEP line on one or more of the steppers.
  A couple parameters setups you need:

1) The proper parallel port address for your PC set up in the Mach parameters (usually 0x278 or 0x378, but if using a PCI card a different sort of address).  Mach should have more information on this in their manual.

2) The proper STEP and DIR setup parameters:

STEP X - Pin 2
DIR X - Pin 3
STEP Y - Pin 4
DIR Y - Pin 5
STEP Z - Pin 6
DIR Z - Pin 7
STEP A - Pin 8
DIR A - Pin 9

Jeff

[josh yoder]

That is how I have it set up. Can I post photos on this thread?

[Jeff Pollard]

Hi,

  Yes there is a way to add attachments that are photos.  I haven't done it so don't know the method though.

  A way to see if the port is being communicated to.  Jog the X axis forward and note the voltage of pin 3 (the X axis DIR pin).  Then jog the other way and see what value you get.  The two voltages should be something less than 0.9 votls for a logic low, and something higher than 2.9V for a logic high.

Jeff

[josh yoder]

I get a steady .3v on pin 3. Jogging the axis doesn't change it. I have the port address set at 0x378. According to the device manager this is the correct address. Is this a computer problem? Device manager says the port is working properly.

[Jeff Pollard]

Hi,

   This is either a software set up problem or a PC parallel port problem.
    In my experience, device manager saying something is working correctly means nothing.
   Are you sure the axis is marked as enabled (Green check mark as opposed to red X)?

Jeff

[josh yoder]

Yes. They are enabled. I watched Dave Gatton's tutorial and set my program up the same way. He didn't have any instructions for the input signals. I have them all disabled. I understand these are for home and limit switches,so the axes should jog without any inputs programmed, right?

[Jeff Pollard]

Hi,

  You should be able to move without limit switches, but the best place to find out how to set up Mach3 would the manual. 
  If you have another computer you can try, you might want to do that in case the one you are using has a bad parallel port.

Jeff

[josh yoder]

I did some tests and found the parallel port isn't working. I'll try another computer.

[cda...@roadrunner.com]

Hi, I'm a total newbie to CNC also, this is my first post.

I have the same problem but here is what I discovered... According to MACH3 manual the Input signals, to the computer need to be supplied with some current (less than 40 microamps) for “hi” inputs and will supply some (less than 0.4 milliamps) for “lo” inputs.

I found all my readings for "hi"& "lo" to be the same. They all read "hi". 

This is a video on how to take readings https://www.youtube.com/watch?time_continue=7&v=uglCm_qsojk

Hope some one reads this and knows how to fix the problem.

[Jeff Pollard]

Hi,

  A "low" input signal will generally be connected to GND through one of the STOP/Limit switches via a parallel port input.  No worry about amp ratings there.
  The parallel port will almost always have a pullup resistor that will cause the input to go "high" if the switch is opened, or nothing is attached.
  That would usually satisfy the "high" requirement.
  Most often the voltage is what is considered.
  0.9V or lower is a "low" (depends on chipset used)
  2.1V or higher is a "high" (depends on chipset used)
  You can add a 4.7K resistor to give more pullup:
3V3 or 5V ------> [4.7K resistor] ---------- Input pin (then the rest of your input circuitry attached to the pin as normal)

  Of course the software parameters need to be set up properly so the programs knows where to read the port input data.

Jeff

[Chris Dalyai]

I had an individual who had a computer business and developed software help me with my problem, He has also built a couple CNC machines. I have a Dell OptiPlex 320. He worked with me for One and a half hours studying and changing BIOS settings, his suggestion was to ditch the computer. He said I could try adding a parallel port card but the way the mother board configuration was I would have to do some reconfiguration. So I will be getting another computer.

I’ll keep you posted…

[Chris Dalyai]

Ok, so I got another 32 bit computer and every thing loaded and ran like a champ.

Used the same settings as before and it works.

When I checked the old computer driver settings for mach3  their was question marks "?" on the drivers.

For some reason mach3 could not take control of the LPT port. Even though the mach3 built in driver test showed an excellent reading and the mach3 program showed the driver loaded.

[Jeff Pollard]

Hi,

  I've had PCs where the parallel port just dies.
  Not sure what happened to your system, but perhaps the port just failed.

Jeff