Breakout boards problem

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18 Oct 2019 09:12 #148177 by aaron
Hi
I have in intermittent fault with my linuxcnc router. I have two motors running the x axis and one of them sporadically clunks and whines when it first starts up. Sometimes it is able to home and I can run a job okay and other times I have to turn it of and leave it for a while. It has been running very happily for a number of years, and I cannot think of anything that might have caused this.

I have swapped over drives and motors and the error stays on the same axis. I have checked all connections, but no improvement. The only thing I can think is that it is the cheap Chinese Parallel port brake out-board, with optiisolators? is this the kind of error that anyone else has experienced?

I just spoken to my favorite component supplier (Zap Automation) and they are saying that nobody uses parallel port connections anymore. I have heard of Mesa boards, but do not know what they are.

Can anyone offer guidance to a fellow traveler (admittedly one very far back on the road).

Thanks

Aaron

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18 Oct 2019 09:27 #148179 by tommylight
Replied by tommylight on topic Breakout boards problem
That points to a mechanical failure on that axis, overheated motor that lost its strength, or a failing drive.
The first thing you should try is to set the step_time higher as that would help getting better signal through BOB to the drives.
Another thing to try is to wire drives to directly to parallel port.
Usualy i tend to awoid using cheap BOB as they do cause much more trouble than they are worth.
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18 Oct 2019 12:46 #148188 by Todd Zuercher
Cheap breakout boards are not worth much, so they must not cause much trouble ;)

I agree, check for a mechanical failures. But don't count out a wiring issue, a bad motor cable or plug can cause heaps of trouble for a stepper.
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19 Oct 2019 06:57 #148293 by aaron
Replied by aaron on topic Breakout boards problem
Thanks for replies guys.
Bare with me, I am not good at this stuff.

First thing to say is that the problem is now occurring in the z axis as well. It seems that the machine struggles to home itself, but once it does it works as normal.

I don't think it is the drives because I have swapped them over and the problem persists on the same axis. These are nema 34 motors and once they get going they run fine so I don't think it is the motors. I have tightened all electrical connectors, swapped out pcs and par-port cables and still the problem persists (sometimes). However I am not sure how to change to change the step-time higher.

Also, I am not sure what your verdict is on these breakout boards. Are they cheap because they are simple and reliable, or cheap because they are of poor quality? If they are crap what is the alternative? I am running this thing on four Motion Control MSD880 drives, could I use some kind of machine controller instead?

Thanks for reading and any responses

Aaron

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19 Oct 2019 07:56 #148298 by tommylight
Replied by tommylight on topic Breakout boards problem
Cheap BOB's use low quality/speed stuff so the output signal is to slow/degraded/low voltage etc.
Check out Mesanet.com, most of us use their controllers.
The step_time is in the ini file where your config is located, usually /home/user_name/linuxcnc/configs/name_of_config

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19 Oct 2019 08:29 #148306 by pl7i92
Replied by pl7i92 on topic Breakout boards problem
Hi i use most this chineese BOB

can you specifi more
is it a TB6xxxx Board RED BLUE
a Mach3 5axis Green Blue
a 2Relay or more board

can you upload your INI and HAL

i think you have been gone with low latency values
you can easy go for 80000 and more THe board will only get 60k steps per second
you may need only 10k or even less

this sounds as it is not propper set
look here at 1minute

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20 Oct 2019 11:03 #148402 by aaron
Replied by aaron on topic Breakout boards problem
Hi
Thanks for your replies.
This is a link to the pdf for the breakout board I am using. edoc.pub/user-manual-5-axis-breakout-board-pdf-free.html . It calls itself 'ECG-Savebase' or something. And INI and Hall files are attached.

Could you explain how I would use one these Mesa motion controllers and which one I should go for. Are they available in the UK?
My machine currently has two steppers to run the x axis and one each for y and z. All steppers are connected to Motion Control Products ltd MSD 880 drivers. I also occasionally use a 4th rotary axis. This means I cannot use the step config wizard to configure the system, and everything has to be done in HAL and INI files, which I find very difficult/impossible.

With a Mesa motion controller do I still use the MSD drivers or does Mesa do all that? Then how do I configure it, I assume there is no wizard for my application?

Once again thanks for your time and efforts

Aaron
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23 Oct 2019 23:15 #148651 by andypugh
Replied by andypugh on topic Breakout boards problem
Zapp is somewhat wrong about nobody using parallel ports any more. But he might well be more used to folk using Smoothsteppers with Mach.

It's odd that your machine should just stop working, though, if nothing has been changed.

I would first check for mechanical issues, such as loose or cracked couplings.

Also check that your stepper power supply is still working at the nominal voltage and isn't on its way out.

The Motion Control Products drives seem reasonably reliable in my experience.

The closest source to the UK for Mesa stuff is probably eusurplus in Portuga . Though I have ordered direct from Mesa several times with no issues.

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24 Oct 2019 07:02 #148674 by aaron
Replied by aaron on topic Breakout boards problem
Thanks Andypugh
I still do not really understand. These Messa boards, are they just breakout boards only better?
Could you recommend one for my application?
Cheers

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24 Oct 2019 16:33 #148712 by andypugh
Replied by andypugh on topic Breakout boards problem
The Mesa (and Pico, and General Mechatronics) boards are equivalent to the Smoothsteppers that Mach3 users use. (except a bit cheaper)

They generate step pulses (and PWM, and count encoders) in an FPGA on the board, so that the LinuxCNC computer only has to send step rates etc digitally, rather than bit-banging every step itself.

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