what happend to my post

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This topic contains 3 replies, has 2 voices, and was last updated by  BrianV 1 month, 1 week ago.

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  • #3345

    Jeff Morris
    Participant

    So I had a post up and it mysteriously disappeared. That says alot…. so here it is again….
    Hey Guys,
    So, I have a 4 axis pro-board, Im using with OpenFoam. Its an older board, rev 0 copyright ’04. Anyways, I recently had to change out my TB2 driver. I got about 20 hours of normal behavior out of it before it started running incomplete profiles out of my left tower. In other words, on the software end, openfoam, it thinks Im running the complete profile, however, in realtime my X1, TB2, is ending about about 2” shy of where it should. This is drastic considering Im only running 6” chord airfoil. So this is where it gets weird. When it ends short of where it should, Im cutting a straight trialing edge and tapered leading edge. The span is 13.7”, with a tapper ratio of ~5:3. Cutting 10” from the tower face with 34 inches between the towers, running at about 11”/min. (maybe im giving too much info, but youll understand why in a sec). So like I said Im ending short in the X1 direction. However, if I cut a span without a tapper, rectangular planform, it ends exactly where it should. I started messing with stuff and that’s when I noticed if I slightly moved the wire going into the X1 motor I would get a high frequency noise that was generating in the motor. I re-ran my tapered wing and that’s when I noticed I was getting really pulse(y) behavior out of my X1 motor( if that makes sense, it was running really choppy compared to the other motors). I then changed my X1 and Y1 connectors and noticed same behavior followed TB2 channel and wasn’t coming from the motor itself. The motors are the Powermax2 1.8 (Model:p21nsxc-lss-ns-03). I crimped a new male connector for the motor, then switched my connectors back, so that motor X1 was again on TB2, same high freq. noise was still coming from the motor, also note the noise was coming from the other motor when I switched them. I decided it was time to show my boss. I showed him how the motor was making a high frequency noise. I turned the unit off, switch motors and when I powered back on I got nothing out of TB2. Where do I even start in trouble shooting, I was going to ask if there was a way I could test to see if the driver was bad, but now im not getting any movement out of it. Any help is greatly appreciated.

    I guess I should have had more concise questions. Is there a voltage range I can test on TB2 when the board is powered on, but static???

    #3346

    Jeff Morris
    Participant

    Add on: I tested the AC coming off TB2, all zeros. Can this be pinpointed as a driver issue?

    #3347

    BrianV
    Keymaster

    Regarding what happened to your post: within the last 2 weeks, I spent ton of time and energy redesigning the website – there was likely some ‘dead zone’ where stuff put on the old site was not duplicated to the new site.
    My apologies. I checked my archive of the ‘old’ site, and your post is there (February 9, 2017 at 11:36 am), I have duplicated it below for reference:
    ————————————————————–
    Hey Guys,
    So, I have a 4 axis pro-board, Im using with OpenFoam. Its an older board, rev 0 copyright ’04. Anyways, I recently had to change out my TB2 driver. I got about 20 hours of normal behavior out of it before it started running incomplete profiles out of my left tower. In other words, on the software end, openfoam, it thinks Im running the complete profile, however, in realtime my X1, TB2, is ending about about 2” shy of where it should. This is drastic considering Im only running 6” chord airfoil. So this is where it gets weird. When it ends short of where it should, Im cutting a straight trialing edge and tapered leading edge. The span is 13.7”, with a tapper ratio of ~5:3. Cutting 10” from the tower face with 34 inches between the towers, running at about 11”/min. (maybe im giving too much info, but youll understand why in a sec). So like I said Im ending short in the X1 direction. However, if I cut a span without a tapper, rectangular planform, it ends exactly where it should. I started messing with stuff and that’s when I noticed if I slightly moved the wire going into the X1 motor I would get a high frequency noise that was generating in the motor. I re-ran my tapered wing and that’s when I noticed I was getting really pulse(y) behavior out of my X1 motor( if that makes sense, it was running really choppy compared to the other motors). I then changed my X1 and Y1 connectors and noticed same behavior followed TB2 channel and wasn’t coming from the motor itself. The motors are the Powermax2 1.8 (Model:p21nsxc-lss-ns-03). I crimped a new male connector for the motor, then switched my connectors back, so that motor X1 was again on TB2, same high freq. noise was still coming from the motor, also note the noise was coming from the other motor when I switched them. I decided it was time to show my boss. I showed him how the motor was making a high frequency noise. I turned the unit off, switch motors and when I powered back on I got nothing out of TB2. Where do I even start in trouble shooting, I was going to ask if there was a way I could test to see if the driver was bad, but now im not getting any movement out of it. Any help is greatly appreciated.

    #3348

    BrianV
    Keymaster

    4 axis PRO-board, rev 0 copyright ’04. FWIW, I did not purchase the IP for any of the discontinued baords, I don’t have a schematic. All I have is posted in the FAQs.”

    If I cut a span without a tapper, rectangular planform, it ends exactly where it should. I started messing with stuff and that’s when I noticed if I slightly moved the wire going into the X1 motor I would get a high frequency noise that was generating in the motor. The Rev 1 board (and I guess the Rev 0 also) users a “chopper” technology to drive the motors. That is: The driver chip turns full-on. The inductive load of the stepper looks like an open-circuit initially. Current begins to flow, slowly at first, then more rapidly. When the current reaches the defined threshold (set by the little blue trim pots), the driver chip turns off. This “on-off-on-off…” behavior causes an audible ‘whine’ from the motors. So this is not unusual by itself.

    I re-ran my tapered wing and that’s when I noticed I was getting really pulse(y) behavior out of my X1 motor( if that makes sense, it was running really choppy compared to the other motors). I then changed my X1 and Y1 connectors and noticed same behavior followed TB2 channel and wasn’t coming from the motor itself. The motors are the Powermax2 1.8 (Model:p21nsxc-lss-ns-03). I crimped a new male connector for the motor, then switched my connectors back, so that motor X1 was again on TB2, same high freq. noise was still coming from the motor, also note the noise was coming from the other motor when I switched them. I decided it was time to show my boss. I showed him how the motor was making a high frequency noise. I turned the unit off, switch motors and when I powered back on I got nothing out of TB2. Where do I even start in trouble shooting, I was going to ask if there was a way I could test to see if the driver was bad, but now im not getting any movement out of it. Any help is greatly appreciated.

    There are several good hints in the FAQ Missing steps – motor not behaving properly. Take a look through them and give us some feedback

    I guess I should have had more concise questions. Is there a voltage range I can test on TB2 when the board is powered on, but static???The chopping behavior will still be there when the board is powered but nothing is moving. This might register as DC or AC – but I’ve never checked. The basic test is: is that motor locked (e.g. you can’t turn it by hand) when power is applied.

    Some other random thoughts

    • What voltage are you supplying to your board
    • Does it drop or dip when your board is running
    • What is the voltage at the fan connector
    • what is the voltage at the 5V test point
    • Do you have a heatsink? A fan?
    • Is any part getting hot
    • if you can, carefully inspect the solder connections to TB2 – it is possible to torque the screw enough to break-loose the solder connection.
    • there is no binding in your axis (turn axis by hand thru full range

    BrianV

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