Slave axis all of sudden not working

[CNCing]

Hi Guys,

I have a cnc router that has been running Mach 3 for about 4 years without any issues at all. About a week ago my slave axis A is no longer working...If I swap the A axis wires on the breakout board with another input/output it works. No axis will work on this particular input/output "8 COM 9"...so I first replaced the motor driver for the A axis without any change...now I replaced the entire breakout board but still am having same issues with "8 COM 9" ports. I have changed no settings and this issue just happened all of a sudden...

I checked all the settings multiple times and can find no issues at all. This router is for a very busy sign company and it is killing us that it is down, please help if you can.

Thanks,

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[ger21]

Those are pins 8 and 9 of your parallel port.
Are you sure Mach3 is configured correctly? If it is, then perhaps you have a bad parallel port?
Have you tried a different PC?

[CNCing]

Hi, my next thought was to change to a different pc...I though for sure it was the board but it looks like it might be the computer.

I have a serial port and a cable that goes from serial to parallel, would this work? Is there any other option other than using the parallel port?

Thanks so much for the reply

[ger21]

I have a serial port and a cable that goes from serial to parallel, would this work?

No.
If you don't have a parallel port, you need a Mach3 compatible USB or ethernet motion controller.

[CNCing]

No.
If you don't have a parallel port, you need a Mach3 compatible USB or ethernet motion controller.

Do you know if the parallel port can be replaced or do I need a whole new computer?

[ger21]

You can use a PCI parallel port card.

[CNCing]

Ok I just got back from the computer shop and had the parallel port replaced and still exact same issue...

Ports 8 com 9 will not drive any function. Motors will work on all other settings but these...

Changed breakout board
Changed parallel cord
Changed parallel port
Changed motor driver

I'm at a complete loss but in bad need of assistance! Any tips please, I have checked all the settings in Mach 3 hundreds of times and everything looks good, this problem just happened overnight. Could it be an issue with Mach 3?

[ger21]

How do you have them assigned in Mach3?

[CNCing]

Still no success guys...I have tried everything. Today I connected a uc-100 and am now running on a separate computer. No matter which axis is connected to pins 8&9 it will only move in 1 direction. The motor moves when you move back and forth it just only moves in 1 direction.

Connections are...
X 2-3
Y 4-5
Z 6-7
A 8-9

Y & A are slaved. Really desperate for some help on this one

[ger21]

Seems like you've changed everything but the motor?

Swap the pins for the Y and A axis. Does the problem stay with the A axis?

[CNCing]

Seems like you've changed everything but the motor?

Swap the pins for the Y and A axis. Does the problem stay with the A axis?

If I swap the pins the problem will now be the y not the a. Any function I’ve put on pins 8&9 has this problem. I did notice yesterday I was able to get the x function to work on pins 8&9 but nothing else...

Any ideas? I’ve even put another motor on the a axis and have the same problem...

Even when I changed out the breakout board I had the same problem on pins 8&9. I have used this machine for 4 years daily no problem then all of a sudden this happened overnight.

[ger21]

Have you tried completely uninstalling and then re-installing Mach3?
Or create a new .xml file from scratch?

That's the only thing I can think of.

I've never heard of an issue like this, and the fact that is does it with both a parallel port and a UC100 would point to Mach3.

[CNCing]

I re installed the demo version from online on the new computer with the same results

[ger21]

I don't have an answer for you.
If you've changed every single component, including the PC, and get the same results, it's got to be an issue with your setup.

[CNCing]

I don't have an answer for you.
If you've changed every single component, including the PC, and get the same results, it's got to be an issue with your setup.

Ok, I’ll continue to inspect...everything is perfect except for pins 8&9. Thanks for the help, I will let you know if I find anything else.

[john-100]

what happens when you don't have any axis slaved and use the X & Z stepper drivers & motors to test pins 4 , 5, 8 & 9 ?

if pins 8 & 9 still don't work
what happens if you swap over the function of pins 8 & 9 so the direction pin is the step and vise versa
I am assuming pin 8 is now for the step pulse and swapping over the functions of pins 8 & 9
will be an easy way to test pin 9 - its not easy to use a multimeter to see the step pulses

which breakout board are you using ?

John

[CNCing]

Ok, I’ll continue to inspect...everything is perfect except for pins 8&9. Thanks for the help, I will let you know if I find anything else.

Is there a good way to determine if the pins on the board are recieving the proper signals/voltage?

[john-100]

you can use a multi meter to test for the direction signal as it switches between 0V & 5V
but its not going to be easy to see step pulses
depending on whether you have set Mach to active high or low
you might only see 0V go up to 0.1V or + 5V go down to 4.9V depending on the speed you jog the axis


details of you breakout board will help to work out what test point you need to identify and voltages to expect

depending on the BOB's circuit details such as any buffer IC's connecting the printer port connector to the stepper drivers

if you assign the direction signal to both pins 8 & 9 you should see both of the pins at the 25 pin D-Type connector switch between
0V & about 4.5V on an old PC mother board (or between 0V & 3V on the latest design of printer port)

on the BOB's outputs both pins switch between 0V & +5V as you job back and forth
measuring between com and the output being tested with your multi meter

I am assuming the output terminals to the stepper driver are connected to a buffer IC like 74HC244 or 74HC245 that can sink or source about 20mA

on some BOB's with NPN open collector outputs you will not see the output switch

John

[CNCing]

John, thanks so much for all the great info!

I have a 36v power supply, C10 bob, 5v power supply, kl4030 drivers and kl23h286-20-8b. That’s all I really know about the setup. Pins 2-9 I believe are my motor outputs and 10-15 are the limit switches, estop, and 5v supply. It’s been so long since we put it together is hard to remember all the details.

What’s crazy is I changed the bob, motor, parallel cable, parallel port and computer with the same results on pins 8&9. I have a gender swap plug in the end of the parallel port to convert it from male to female. This is the only thing I haven’t changed but I checked it with continuity and it was good.

[john-100]

looking at my notes for the older C10 like this



it uses 1/2 of two 74ACT 245 tristate octal transceivers to buffer the 8 signals in or out of the printer port pins 2 to 9
one 74ACT245 buffers printer port pins 2 to 5 and a second 74ACT245 buffers printer port pins 6 to 9


normally for the C10 to function the 25 pin D-type connector pin 18 has to be grounded = connected to any pin from 19 to 25 via the printer cable connected to the PC printer port
and you have to have the C10's enable connected to +5V

to bench test the C10 without the PC -
without printer cable connected , you will need to add a temporary ground connection on pin 17 from any ground pin 18 to 25

you should find the 1K2 pull up resistors will pull the BOB's inputs for pins 2 to 9 up to a valid high = more than 3.5V
as the 47ACT245 is non inverting the boards screw terminals for the step and direction connections to the stepper driver are also high
(that's +5V without the stepper drivers being connected )


if you short an input pin 2-9 on the D-type connector to ground = either the shell or pins 18 to 25
the corresponding screw terminal should go low = 0V to 0.5V





the new version using surface mounted components uses one 74ACT245 to buffer pins 2 to 9

John