Initial Config help needed please

egropp wrote:

I am looking now for an LPT board to drop in and try..
I am not using pin 1 for anything...

Also.. I guess i cannot seem to get my head aropund the fact that X and Y work ok and all pins show the same output voltages.

all pins show voltages , it's the fact that the faulty step pin is not switching or pulsing between 0 volts and 5v , and is staying close to 5v all the time
it is the act of the pulse that makes stepper motors move , i.e move to the next step and this constant pulsing which makes the motor turn .

your thinking perhaps as if it was a dc motor where you apply a voltage and the motor turns , steppers are totally different

the direction pin is either 0 volts or 5v and this denotes the actual direction the motor turns i.e cw or ccw

hope this helps understand how stepper drivers work

Inverting the pins shows the same voltages. the only diff is the direction pin in that the voltages are on the other direction
example.
I get 3.36 going left and 1.72 going right, if i invert the pin, i get 3.36 going right and 1.72 going left. (this is on a desktop PC)
I have a laptop that will actually run all 3 axis but the voltages are higher (the step pins have right at 4.79 volts and the direction pins show 4.79 in one direction and 0 in the other)

I installed an add on lpt board last night, but for some reason i cannot get kcam OR linnuxCNC to use this board. if i put a meter on the board (while i cannot control anything with it), i see 3.36 volts.

Not sure now what is happening and if i am now just chasing my tail.

Every pc I have tested so far gives me the same 3.3 volts on the pins.

This sort of leads me to believe that this would be the correct voltage here, but why does this work for a laptop and none of the pc's i try will run the Z axis.

I installed an add on lpt board last night, but for some reason i cannot get kcam OR linnuxCNC to use this board. if i put a meter on the board (while i cannot control anything with it), i see 3.36 volts.

You might want to pursue this card.

Might look here...
www.linuxcnc.org/docs/2.4/html/examples_pci_parallel_port.html

and here...

linuxcnc.org/docs/2.5/html/hal/parallel_port.html
Also take a look at using Port index

Couple things,

When checking voltage I would concentrate on the direction pin, in a perfect world 5 volts one way 0 the other. The step pins you would be better off reading with a scope.
Linuxcnc needs to be using the port for the numbers to mean anything, if nothing is controlling the parallel port the voltage may "float".

Rick G

Hi

Reading the thread over a couple of times, I cannot see anything about how you are powering the BOB?

It has a 5v regulator able to take 6-40v ( or a USB port with limited current use) , which supply 5v to the input pull-ups and enable pins.
They require correct jumpering to work.

Without any help it can get, JT's reason may be the answer, the voltage / current from the parport alone is not enough to drive the enables, limit and estop connections plus the drivers.

regards

OK.. Went back to basics last night...
the bob is powered by a wall transformer

From the laptop, all axis work without issue

From the PC, only the x and y work running stepconf, I swapped the y and z axis wires at the bob only.. reran stepconf and now as expected, testing the y axis runs the Z axis motor (the z axis test in stepconf still controls nothing).
If i were using only 1 machine for setup, this would lead me to believe that the breakout board was bad. But because everything works from the laptop, i am confused.

I installed an add on lpt board last night, but for some reason i cannot get kcam OR linnuxCNC to use this board.

You need to pursue this, everything points to your parallel port being defective or unable to supply enough current to operate your system

Read my FAQ www.linuxcnc.org/index.php/english/forum...-parallel-port-cards and follow the instructions for
identifying the ports and getting Linuxcnc to use it.

3.3v ports can be a problem. My workshop machines are quite old and have 5v outputs.
When I tested a small modern computer with my mill, it would hardly work.
I had to reduce the length of the parport lead to a 1m one before it would operate it, which was purely down the the lesser voltage getting lost
in the resistance of a longer cable run.

regards

But because everything works from the laptop, i am confused.

Might be a good time to get that new lpt board working as was posted earlier. It not working may just be a case of finding the correct address.

Rick G