halscope in linuxcnc

I hope this is in the right location for this question,If not forgive me. The question is has any one used the Halscope section that is in the Linuxcnc to monitor the outputs of the step and direction signals on the port pins while using the linuxcnc.Im trying to study the halscope tutitorals and it gives me the impression it does.Im thinking it might only show whats at the pins at the parallel port that is connected to the Breakout board but not beyond.I have a mechatronics 3-axis control board that uses the A3977SEDT chip with some opto-isolators from the step and direction pins before going to that chip but one axis will not turn a stepper.Seems like its not getting the step signal to that chip.Im going to order those ICS and just replace them.I switched them with the ics from the working axis.and that axis still did not work. dont think there bad.I saw on line where you can use the audio input of your laptop as a O-scope if I can do that I can follow that step pins signal through the opto-isolator to the Stepper IC.

Halscope is a very useful tool but it can only plot Linuxcnc pins and signals etc that you can monitor in halshow. Hantek make some cheap USB oscilloscopes. I ended up purchasing one as there are some things Halscope can't see

Here's and example Halscope plot of torch voltage on a plasma machine.

http://www.cnczone.com/forums/attach...d=388196&stc=1

Thank you for your reply i didnt think it would show any thing past the pin,was hoping to be able to see the waveform past the opto-isolator. the out put of that optoisolator goes directly to the stepper motor driver ic.Its the step pulse from pin 6 of the parallel port to the opto-iso input then to the out put of opto-iso to motor driver ic,I can measure any type ov voltage on that pin,nor at the output of that opto-iso either.I know that pin works because I can connect it to another breakout board and it works.

I would forget about Linuxcnc and step generators and purely focus on troubleshooting the card. If you jumper a voltage to the pin, does the opto fire? Some par ports work in a different way to the Mesa hardware I'm used to and switch ground or something so the wiring to the stepper is different to how I do it.

Im thinking about pulsing 5-volts at the out-put of the opto-isolator and see if the motor will step,like i said earlier (i think) I switched both opto-isos,and stepper motor ic and they worked ok in the other axis location,and the lands of the ckt.board shows direct connection from out-put of opto-iso to motor ic.been comparing resistance on each axis,(all three are just alike). so far havent found any thing.But something is wrong thats why that axis is not working,

Forget the pulsing and observe what happens with your multimeter if you jumper 5 volts to the pin

Another testing option is to use LinuxCNCs parallel port tester:

LinuxCNC Documentation Wiki: Parallel Port Tester

and manually toggle the output pins and trace them with voltmeter an each stage from the parallel port pins to the IC step/dir pins
(you may have to change the parallel port address at the top of the ptest.hal file)

Im going to try both of you guys suggestions,because if im getting a pulsed wave form on the parallel pin for step I cant read it on a volt meter,
will try to down load the parallel port tester for linux,and use that too.First thing I will try is to put 5 volts on the input of that opto-iso and try to read the output it should be 5 volts also,I do know the opto-isolator is good because it works on the other axis.Could be something is keeping it from changing states (low to high) could be a capacitor shorted to ground making that signal stay low....