UCCNC Plasma - constant velocity output ?!?

[stivemaster]

Hello, I'm releasing a new topic, because despite the assurances of the developers, this feature does not work. In the topic in which I describe the problem,
no one has answered me for several months!
Unable to attach link! viewtopic.php?f=2&t=2792&start=20

[cncdrive]

I answered in the original thread.

[stivemaster]

Hello, after the additional tests I am very disappointed. I refuse to use this function because it does not work correctly. If the figure is simple, it may work, but with small holes or a series of turns, its work is incorrect. I also understand the logic, why anti-diving works at G00 !!! It also works for moves on the Z axis !!! There is no logic in this.
Unfortunately, this is not all. I did not install the AHBB controller I bought on a machine for the reasons we discuss in this topic. I turned it on a dozen times to try different settings. While looking at it, I was badly impressed by the solution with two external power supplies 5 and 24 volts, but I decided I would survive it.
But yesterday, as it is on the table without ever inputs or outputs, said Puck ..... and the red diode went out. Now the 5 volt part does not work!
I'm thinking about when exactly to put a red cross on the UCCNC and move on.

[cncdrive]

For the antidive it does not matter what the hole size is, it is simply checking the programmed feedrate and if it went lower than that then it inhibits the Z.

If the red LED is on means that there is a series overcurrent somewhere on the 5Volts part.
So, something is drawing too much current or is in short circuit.
Since it is the 5V powersupply it could be on the 5V output or the step/dir lines or if you have anything connected to port 3. then that could be also.
I would try to disconnect everything from the AXBB-E to see if it resolves the issue and then connect things back one after the other to see which causes the issue.

Another possibility is if something went bad internally in the board, e.g. an overload on a step/dir vuffer output could cause a permament short circuit in the 74HC14, however if it fails usually it fails in open circuit so it is not likely to be the cause.
Again another possiblity is if a chip or plasma dirt went inside the controller causing an internal short circuit.

[stivemaster]

I already wrote that the controller is new and not placed on a machine at all, but still sitting on the test table! I did not include anything on the inputs or outputs. They are only configured to monitor the operation of the LEDs!
And you mean the red LED should NOT be lit? Because it shone all the time when I bought it.

[cncdrive]

That the red LED always shined is not possible, because it is a latched overcurrent protection which means that when it shines then the power to the controller's logic part is totally disconnected.
So, if it would always shine as you wrote then the controller would never worked.

You wrote that you did not include anything on the I/Os?
Then how did you verify the antidive function?
Earlier you wrote that it is not working which means that you tested it somehow?!

[stivemaster]

I tested on UC400ETH controllers on two of our machines that we made for customers.

[cncdrive]

OK, I understand. Then it is probably that your 5V powersupply has a problem.
The overcurrent protection IC is directly on the 5V input before anything else.
So, if an overcurrent occurs anywhere in the circuit then the IC latch protects the circuit, so the board will not damage.
This protection is useful, because there were several cases when customers overloaded our other motion controllers' with shorting pin26. of the IDC connector to the ground, but that pin is the +5V and not ground and so if the powersupply is powerful enough and does not have a short circuit protection then this could damage/melt PCB tracks.
But this IC cannot stand overvoltages, so if an overvoltage is input to the 5V input, I think it is 6 Volts max. then the IC damages.
The good thing in the bad is that the IC still always protects the output even if it gets a high overvoltage and damages.
In other words it damages in a way that it still not outputting overvoltage on it's output, so the expensive logic parts on the board will still not damage.
However the board will not work anymore and the IC has to be replaced or bypassed.
It is easy to bypass the IC with a piece of wire from the input to the output, but without the IC there will be no more overcurrent protection.
It is also possible to replace the IC if it did not burn the PCB too much.

And I would also check that powersupply, because if that IC damaged means that the powersupply is not OK, it gives overvoltages.

[stivemaster]

Thank you, but so far it has never occurred to me to repair a controller before it is put on a machine. And I also use Chinese controllers!

[stivemaster]

Hi AXBB-E is back from repair and I decided to write a few lines.
From the conversation with the one who is repairing it, I am left with the impression that this controller is not made properly. When I saw that a second external 5 volt power supply is needed, I decided that it was made for galvanic isolation.
But inside, such insulation is not made !!! In my case, an AP2401 element had burned out, which no one knows what role it plays in the circuit, instead of putting a 7805 and everything is fine, without the need for a second external power supply!
Even the Chinese in the F2100B have 3 or 4 galvanically isolating DC / DC inside because they supply 220 volts.
Hopefully in the future you will review the scheme and clear the mistakes.
Otherwise, regarding the constant speed, you did not answer me - why does the function work at G0?