help - y axis only moves in one direction

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iamtracyp
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help - y axis only moves in one direction

Post by iamtracyp »

hi - looking for advise on trouble shooting an issue with my vendor on my brand new table. my y-axis only moves in one direction when i use the arrow keys on the keyboard, and when i try to cut a pattern. it was intermediate at first, but now consistent. i've sent the pc, control box, and connector cable back to the vendor several times (as well as email, pictures, and videos). they say it's working fine. when i swap the x and y cables on the back of the control box (and unplug the x2 cable) the problem migrates to the x axis. so logic points to a bad port on the back of the control box, but is there any other explanation why it would work with the vendors equipment but not with mine? i have a burntables 4x4 table, hypertherm 65 plasma cutter. thanks, tracy
tcaudle
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Re: help - y axis only moves in one direction

Post by tcaudle »

So when you swap the motor cables are you saying the problem stays on the same AXIS (y) with the X motor plugged in or it stays on the Y motor?
An axis not moving in a direction menas the DIR signal for that axis is not working. It should change for high to low and back based on the direction . Moving means the STEP signal for that axis IS working. Look in the Ports & Pins / Motor outputs and find the port (1) and pin for Y for Step and dir. Those correspond to the pins on the 25 pin parallel port cable. Most common caus of this is a bad 25 pin cable or apin gets bent or the connector is not seated . If its conventional pinout it would be port 1 pin 5 (pin 5 on the cable) . The good news is you can trace the DIR signal with a meter starting at the drivers . Its probably not a motor or driver if they are really testing it . Motors typically will not spin at full speed in just one direction.
iamtracyp
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Re: help - y axis only moves in one direction

Post by iamtracyp »

hi thanks for your reply. to clarify, the symptom is my y motor only moves in one direction. so when i plug the x motor cable into the y port on the back of the controller, then the x motor only goes in one direction (and when i plug the y motor cable into the x port on the back of the controller, then the y motor moves correctly back and forth with the arrow keys). i'll take a look at the ports and pins as you suggest. but how do I use a multimeter for this trace, ie: where do I put the leads? thanks again.
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acourtjester
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Re: help - y axis only moves in one direction

Post by acourtjester »

sounds like the BOB board to check swap the pins for the X and Y motor signals, as said above if the DIR signal does not change the motor will only move in one direction. swapping the signals in Mach's ports and pins for both X and Y it the problem now shows the X with a problem its the BOB. Your signal pins may be different then those shown :lol:
swap.jpg

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msimpson99
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Re: help - y axis only moves in one direction

Post by msimpson99 »

I would take a closer look at the system hotkeys setup. In what you describe 99% of the time this is where the problem is. Another area to look at is to make sure your Dir pin for that motor is set correctly. If you know your keyboard config is setup correctly and you are using the correct dir pin then you need to start tracing the dir pin all from the output of your parallel port all the way to your controller.

All that said, make sure your parallel port is setup correctly in your PC bios. Note that this only applies to builtin parallel ports. It should be setup as an EPP port. If it is not, then you will not have control of some of the output pins. Most pci and pcie parallel port add on boards are EPP unless they are real old.

One last thing. I have had some manufactures of PC boards get the EPP and SPP settings reversed.
tcaudle
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Re: help - y axis only moves in one direction

Post by tcaudle »

System hotkeys won't keep it from moving with G code. I think most of that box is hand wired so find the Y driver card/module and the DIR (or CW?CCW pin. put your meter on it and the COM (common) pin and when you change direction it should shift from 0 to 5 volts and back on each direction change. Check your other drivers. If you have the signal at the driver pins then its the driver or the connector . If its missing its BEFORE the driver(s) and back on the BoB .

Actually the most common problem is between the PC and the BoB . Look at the Ports and pins for Y DIR signal in MACH. now get a pinout for the DB25 connectors (male & female are opposite and find pin 18 (GND) and the DIR pin for Y and see if you can make it flip by changing the direction in MACH.

You will probably have to "fake" the E-Stop input when you unplug the 25 pin cable. Just open MACH and the Ports & Pins / Input Signals and the E-Stop input . Flip the Active Low from red X to green check (or vice versa)) so you can come out of reset with nothing plugged to the parallel port.

The inside troubleshooting won't be that easy but if they used off-the-shelf drivers . you can get a part number and you should be able to get a pinout of the driver. Same story with the BoB. The Y DIR stays on the same pin all the way through.
iamtracyp
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Re: help - y axis only moves in one direction

Post by iamtracyp »

hi everyone - thanks so much for your suggestions. turns out (after swapping around cables piece by piece inside the control box to prove out where it was really failing) turned out to be a bad driver for the Y-axis. we replaced the driver and the Y-axis started working properly. again really appreciate all your suggestions!
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