Stepper motors only move in one direction

-After putting our system through a hardware upgrade (keeping the same hard drive), the motors on all axes of our Sherline 3 Axis mill can only move in 1 direction (e.g. Page Up > Z moves down, Page Down > Z moves down). Only the computer hardware was changed so I'm confident it isn't the parport connection itself or the control box.

-Everything in the UI seems fine aside from the error "unexpected realtime delay: check dmesg for details."

-All config files have been unchanged as they worked on the old computer, but I assume that because the hardware was changed, something should be reconfigured.

-I don't know where to start. Suggestions?

Everything in the UI seems fine aside from the error "unexpected realtime delay: check dmesg for details

I would start here. If you have changed your computer you need to run the latency test on the new computer.
The latency test you let you know if the computer can run the base and servo threads speeds that your configuration is set up for.
linuxcnc.org/docs/html/install/Latency_Test.html

Steppers moving in one direction is often caused by the direction pin not being properly connected or configured or possibly a weak parallel port.
Have you checked the voltage of the parallel port?

Rick G

Max Jitter, is about 27,000. According to the website, this is acceptable for running LinuxCNC.

After testing pins:
all pins seem normal with directional pins toggling between between ~0.09v (off) and ~3.25V (on) and stepping pins toggling between ~0.09V(off) and ~0.5V(on).

This leads me to think that the problem lies in the control box to the stepper motors, even though that setup remained unchanged throughout our computer change.

Is there any other source of a problem that I haven't considered?

Is this the control box you are using?
www.sherline.com/8760pg.htm
Which states the requirements are...

Parameters:

∙ Logic high levels should be greater than 2 volts.
∙ Logic low should be less than 1/2 volt.
∙ Step pulses are active low.
∙ Step pulses should be at least 22 microseconds long.

In which case the voltages for direction look good.

Rick G

Yes that is the box I am currently using. How do I troubleshoot this?

Couple of things,
You need to find out what is causing the

unexpected realtime delay:

.
How long did you run the latency test, and what did you do while testing it?
wiki.linuxcnc.org/cgi-bin/wiki.pl?TroubleShooting

Are you using an on board parallel port or a PCI card parallel port?
You might try the parallel port tester...
wiki.linuxcnc.org/cgi-bin/wiki.pl?Parallel_Port_Tester
Do you have another parallel port card to try?
Low voltage parallel ports 3.3 volt vs 5 volt can be a problem for come controllers, however the specs state 2 volt is sufficient.
Are you checking the voltage at the parallel port on the computer or inside the control box?
Can you go back to the original computer and test operation?

Rick G

is this a Laptop ?
your problem is more than likely the realtime error your getting , this has stopped is what it's telling you
it is highly unlikey to be your interface if it was working ok before , and as you say nothing has changed

however there are a few changes required to your config , to bring it up to date
i would suggest running stepconf and producing a new configuration .
and then if you want just edit the old values back in , is a fast way .

the only item that makes the steppers reverse is the direction pin , this toggles between 0v & 5v for forward & reverse )
this could indicate a poor parallel port ( especially laptops ) if the logic levels cannot be sustained correctly
it may well be the new pc required the direction pin to be inverted , due in part to the internal pullups . but i doubt it

but as Rick says the more important aspect is the realtime delay