initialization

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Re: initialization

Postby dezsoe » Wed Nov 01, 2017 10:57 am

Silor,

Now I see your problem. When one of the pins on UC100 gets power from the DB25 connector, it gives some power to the controller chip in UC100. Not enough to work, but enough to malfunction. When the USB is gets connected the UC100 will not start normally, as it is in an unknown state. (Once I had the same problem.) So UC100 have to get power from the USB first and only after this can any high input get to its inputs. Always connect USB first and only after this power up the other side.
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Re: initialization

Postby cncdrive » Wed Nov 01, 2017 1:39 pm

Yes, that is possible to happen with an unisolated BOB.
It is really not recommended to use a BOB which has no isolation (mentioned in the safety notes section of the UC100 manual), because just like with an LPT port it is possible to damage your computer if the BOB gets an overvoltage.
And using an unisolated BOB with the BOB already powered when the UC100 is not could possibly cause problems if the BOB puts voltage on the I/Os of the not powered UC100.
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Re: initialization

Postby Robertspark » Wed Nov 01, 2017 2:16 pm

Sailor

Which bob are you using do you have a webpage link?
Rob

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Re: initialization

Postby Sailor » Wed Nov 01, 2017 2:29 pm

I have a small 5 VDC supply for charging phones and such.
Interesting since my last rant, I power cycled the PC several times with the BOB not connected and the motion controller initialized as it should. I then reconnected the BOB and lo and behold, it initialized as it should, that was with the stepper controller off. I turned on the stepper controller and cycled the PC again, the BOB was connected to both the Motion Controller and the Stepper Controller and the motion controller initialized as it should have.

I can't put a finger on which is the culprit, again once the BOB that is isolated comes in, perhaps that will resolve the issue. I can't explain it to a 6-year-old because nothing is consistent.

dezsoe wrote:Not enough to work, but enough to malfunction. When the USB is gets connected the UC100 will not start normally, as it is in an unknown state
That makes total sense to me, had not even given that a thought. Perhaps I should use a USB port for power to the BOB, or better yet, delay power to the BOB until the PC is up and running. I can power the Stepper Controller and the BOB via the same switch.

Robertspark wrote:Which bob are you using do you have a webpage link?
I ordered the C83 needs two independent 5 VDC sources and both ends are isolated or buffered.
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Re: initialization

Postby Sailor » Wed Nov 01, 2017 2:55 pm

Unfortunately, the solution of not having the MC initialize may not be complete.

One of the situations was nothing but the MC (motion controller) was connected to any port on the PC and only connected by the USB cable, of which I used no less than 4 different cables and the MC did not initialize most of the time. However, as long as the BOB is not connected and it is plugged into the unpowered external hub (at this time) it seems to always initialize, so far this has been the case. Perhaps there is a small delay in the hub powering up its circuits and the PC is then prepared to connect with the MC. I don't know what the answer is.

I think we can eliminate possibilities and eventually get to the solution, but to really know would require sophisticated equipment and knowledgeable engineers.

My best solution, I think is that I continue to use the external port. Replace the BOB with one that is isolated and has power on both sides from isolated sources as well. Maybe power up the BOB and Stepper Controller after the PC is up and running, for this, I will experiment to see if that is necessary.

One other detail, the external USB hub I am using is a high-speed hub which may have something to do with the timing of the digital signals. Don't know, but adding it to the system improved the initialization of the MC. BOB must be the next culprit.

It has been a long long time since I had to work with high-speed systems at this level. Usually, I just plugged them in and they worked. I have been out of the PC field for over 7 years and equipment service for 35 years and much has happened since then. Worked as a CNC Service Engineer before Microsoft existed, What took an entire cabinet to run a mill or lathe can now be run from a tablet and something like the UC100 although more is needed to get the feedback and positional accuracy. Simply Amazing.
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Re: initialization

Postby cncdrive » Wed Nov 01, 2017 2:58 pm

I can't put a finger on which is the culprit, again once the BOB that is isolated comes in, perhaps that will resolve the issue. I can't explain it to a 6-year-old because nothing is consistent.


If you powering some I/Os prior to the UC100 getting it's power via the USB port basicly explains the inconsistency.
The thing is that a microcontroller or SOIC (like the USB chip is) can go into a parly powered up undefinable state if it is powered through it's inputs via the parasitic diodes inside the inputs.
I experienced the same several times when I was just learning microcontroller programming about 2 decades ago.
And basicly how it is documented is that this is an unwanted situation with unpredictible results. So, you can't define or predict about what and how things will happen. It is like a russian rulette or a random generator.
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Re: initialization

Postby Sailor » Wed Nov 01, 2017 3:17 pm

cncdrive wrote:It is like a russian rulette or a random generator.
That helps me better understand what is probably happening. Of course, I will put the new BOB in when it gets here, in the meantime, I will plug the BOB in after the system is initialized, seems to work fine at that point. I understand the risks involved with an unisolated BOB, it will only be a few more days.

To be sure, by powering the C-83 BOB from the two isolated sources, to prevent ground loops I believe, will I still have to delay powering the BOB until the PC is up and running, or will this BOB prevent power being fed back to the UC100 because they, the inputs, are isolated? I don't have the schematic in front of me so I am unsure. Or as a minimum delay power to the side connected to the UC100? Just wondering?

Again, I want to thank everyone who has contributed to this problem. I came in ignorant and now I know a little.
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Re: initialization

Postby Robertspark » Wed Nov 01, 2017 5:48 pm

A c83 is not a breakout board, it is an optoisolator board.

https://cnc4pc.com/c83-optoisolator-board.html


What board exactly are you using to drive your drives and receive signals from your switches and sensors?

I don't think the c83 can drive much current.

Even one of these cheap bobs will do
https://www.omc-stepperonline.com/stepp ... st-v2.html
Rob

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Re: initialization

Postby Sailor » Thu Nov 02, 2017 12:10 am

My bad, I was not accurate in my description:

The UC100 can drive my stepper motor controller directly it can just be plugged directly into my stepper motor controller which has a DB-25 connection. Once the UC100 initializes I have no problem driving the steppers. I actually purchased the C83 to optically isolate my 5 inputs, 4 limit switches, and a Z set connection. Currently, the breakout board I have is essentially straight through the pins in, to the pins out and has terminals for each of the active pins on the DB-25 with pull up resistors and filter caps on the potential input lines for connecting switches.

In summary, I am not using this as a breakout board, but the input circuitry is optically isolating my switches It was a good solution for my need to isolate my inputs. I will have to connect my switches to the header pins on the break out board side. My stepper motor controller is directly fed from the DB25 connection so I did not really need a full-blown BOB but something to buffer the stepper motor controller and to optically isolate the inputs. I for the past 3 years, I have not had the inputs or outputs isolated from the printer port on my Xp machine. A short (about 100 VDC) went through a switch circuit and took out my Xp machine, thus the Win 7 machine and the new motion controller, I don't want to go through this again so I want to at least try to isolate my input lines.
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Re: initialization

Postby Sailor » Thu Nov 02, 2017 12:16 am

I honestly do not have a clue as to how much current I will need to drive the stepper controller, I built my machine 4 years ago and don't remember the specs for the controller, but I suspect that if the UC100 can drive the circuits, then the C83 will probably be able to drive them, will find out Friday or Saturday for sure. With the board being sourced Output side with 5 VDC each output can handle 20 ma which I think will be enough.
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