I am using Mach 3 with a UC100 connected to a Chinese 6040T CNC router.
Everything has been running fine until this afternoon. The machine was in the middle of a lengthy beveling operation and I went to eat some lunch. When I returned the X and Y were moving along fine but the Z was a couple of inches above the work piece even though Mach 3 was showing that it should be 4mm below the work surface zero.
I stopped the cut to see if I could rezero the Z and backup to the last tool change and start over. Unfortunately, pressing the keys to control the Z resulted in random action. The Z always moves, but whether it is moving up or down is random.
I reset the computer as well as the control box and I double checked the Z configuration in Mach 3, but the issue persists.
Does anyone have any idea how I might determine what the issue is?
I had to troubleshoot that exact problem. Ended up being the parallel port voltage. This should not be your problem since genuine uc100 seem to have 5V output.
Start jogging up and down and see if you can reproduce the problem.
Since the zero goes up, chances are it's not slippage on the axis. Usually gravity makes the opposite problem. That's usually easy to check though, marking the wheel position on the stepper motor at your zero and see if after moving it comes back to the same place when you go to zero again.
If it's not mechanical, it's electronic most likely. Missed step due to one of many reasons. While most people would say that if only one axis causes the problem the problem should come from the driver or cable that connects the stepper, it's not always the case. To troubleshoot the driver, you can try to switch two axis if the steppers are the same. If the problem follows the driver you have a better idea.
If the problem is with the driver you need to get specific info for the particular controller.
If the problem persists it could be from the Uc100. I would check that the output voltage is OK and that your USB port has enough power to drive the Uc100.
As a note, there are two pins that go from the computer to the controller for each axis, a step pin that turns the motor and a dir pin that signals the change of direction. I would make sur that this dir pin is giving the right output.
I'm not as knowledgeable as other people on this forum but having been there before any advice counts.
It is definitely electrical. If I press the PgUp or PgDn key it starts moving the Z-Axis the entire time I hold down the key in the same direction. The direction is just not predictable. I will have to take my meter over to the workshop tomorrow and see what kind of voltages I am getting.
Today I tried another computer running LinuxCNC and another running XP with Mach 3 using the parallel ports and the Z behaved oddly on both. The Mach 3 had the same issue as the Mach 3 computer using the UC 100. The LinuxCNC machine was slightly different. It seemed like it was changing direction the entire time the up or down button was pressed.
As far as the controller, I am using the controller box that came with the router.These tests were all done with the spindle off.
At this point it seems like it must be the controller.
Could be worth a try to check another parallel cable otherwise you will have to open the controller I'm afraid... Really looks like the dir pin is not sending a clear signal.
Another thing to ascertain that the controller is the problem would be to swap axis and see if the problem moves to the other axis.
There's at least three different controllers on the 6040, à beige box, a blue one and a black one. I bet you can guess which one I have.
Yes, if the steppers are the same you should be able to see the problem reproduce on a different axis.
In case you would like to open it up...
In the controller you will find a parallel card, four driver cards and a power supply. The four driver cards are identical but have different configuration. You can swap the driver with one another to check if the problem is with the driver or the parallel port. Just need to reproduce the configuration for the axis you will be mimicking.
The parallel port schematics are somewhere on this forum. And I can send you the schematics for the driver card if you need to troubleshoot it.
I hope you do not have to go this way but if you do, maybe just double check connexions and continuity for a start. Stay safe also, there are large capacitors in there which can be somewhat dangerous.
Well, I went by this morning and switched the X and Z axes. The Z is still showing the same problem and the X worked fine while connected to the Z port.
So at this point should I assume I am looking at either a cable issue or a stepper issue?
You switched the connector at the back of the machine, right?
Although if the direction is the only problem you have and distance is accurate I cannot really understand what is going on. Did you play with the motor settings to see if the pulse width had an effect on the problem?
Next step would be to bypass the z cable. If you can make a bridging connector that would extend the cable from the stepper connector, it will give you the opportunity to plug on all steppers with the all cables.
This should pin point the problem.
Make sure you check the pulse width, if you copy bad motor settings to a new port you will also see the problem stay on the axis.
Not sure if you did this. I know you tried Linux cnc but I'm not familiar enough with it to assume that the pulses are different from Mach3s'.
Yes, I switched the connectors on the back of the machine.
I can go back and try the pulse width. If I remember correctly it says to enter a value from 0 to 5 and all of the axes are at 5.
LinuxCNC definitely behaved differently. In Mach 3 if I pressed the up or down the Z axis would continue to travel in the same direction as long as I was holding it down even if it was the wrong direction. Under LinuxCNC it was like it was trying to change directions the entire time I held down the button.
You wouldn't happen to know what kind of connector it is that they use on the Z axis to connect the stepper to the cable would you? I am not having a lot of luck with their tech support and I would like to just make up a cable and see if that fixes things. Between the language and time barrier resolving anything is difficult.
Yeah... Good luck with that, I've been down that path and didn't find a system to identify connectors properly. Possibly it exists but no luck on my side.
Look at the JST catalog and check following parameters. Pin spacing, pin diameter, and third size of plastic connector.
I got the first two right, which is necessary, the third parameter I got right using a knife...
I purchased the connector from a electronic shop so I cannot give you a reference.
I replaced the connector on the stepper motor since I had no way to test its connectivity and that didn't fix anything. I tested the connectivity of the cable running from the box to the stepper motor and it checks out.
I am guessing the next thing I will need to do is obtain a 4 wire stepper motor to try and see if it has the same behavior. That is about the only thing left isn't it?
If I connect the X or Y to the Z port, they move in the expected direction.
If I connect the Z to X, Y, or Z, it exhibits the same random motion.
If it isn't the controller or the connector then the stepper is the last possibility isn't it?
Does anyone know any specs on these steppers? All of the ones I have are 6 wire.
Well, my machine is running again as of last night. I finally found the correct 4 pin xlr connectors for the back of the controller, but I couldn't get my JSM SM connectors to fit on the end of my cable because the insulation on the conductors is too thick. I ended up cutting the connector off of the stepper motor and directly connecting the wires. Everything is running fine now.
Hi All, new-ish to posting, been browsing for a while.
Had the same issue with a well worn in Taig today. Z jog was up or down totally randomly. Looked at the motor wires, and 1 had popped out of the connector. And now Bob's my uncle.
Just been having issues with my x steppers moving randomly in different directions. After checking a load of other things it could have been, thanks to this thread I went through all of the connections on my machine and found 2 bad ones
One was a direction wire at the stepper and the other was a direction wire at the board.
6040T Z axis moves in random directions
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