Reply with QuoteGood analogy with the meat mincer.... yes if you were working on it and changing the blades... you would unplug it (3-pole isolator), I'll try to remember that analogy
Re: PCB Autoleveler Plugin for UCCNC
Hi Per,Originally Posted by pertakman
That is scary... but in principle, can be caused by something else also, for example the way you control the VFD or the VFD itself. Can also happen due to an error in the VFD, sure, the plugin is suspected, but in fact, it could also be cause by many other things and even if it is caused by the auto leveller plugin and the bug gets fixed you will NEVER get a 100% warranty that this will never ever happen again. To prevent this from ever happening to me I installed a manual safety switch between the VFD and the spindle.
This is where I bought mine, since you are from Sweden, here is a link if you are interested.
Jula 3-phase safety switch
In general, it is a common safety precaution where there is the slightest risk for a motor to start up on it's own, which is the case with spindles directly connected to a VFD. A VFD should be seen as an RPM regulator only, and you would not put your hand in a meat mincer if the rotation speed is set to zero, would you? I mean, you don't really trust a potentiometer or the electronics controlling the meat mincer knife rotation, so why would anyone trust a VFD and all the electronics behind the spindle motor? In fact, there is even a warning in my manual about this, but in my opinion it is common sense that such thing MUST be prevented if manual actions, like tool changing, are necessary, and the way I see it, there are only two options, 1. switch off the mains to the VFD, which is not a good idea to do with every tool change because it takes pretty long time, or 2. install a safety switch which is flipped to off every time a tool change, or something else is necessary to under the spindle motor which requires your hands to be under or on the tool or the spindle, like auto zero or other type of referencing. Of course, this switch is not there to start/stop the spindle, it is there only to prevent accidents. It demands some discipline to flip the switch off every time and switch it on before the G-code is started, but it provides 100% safety if the routines are followed.
Good analogy with the meat mincer.... yes if you were working on it and changing the blades... you would unplug it (3-pole isolator), I'll try to remember that analogy
Re: PCB Autoleveler Plugin for UCCNC
Very good point! Luckily, the spindle controller comes with a simple switch so I can turn off the mains supply easily.
Cheers, Per
Re: PCB Autoleveler Plugin for UCCNC
Hi Cahit,
I just want to thank you for the great work and give you some feedback. I had some issues with FlatCam files, because these where not loaded into the plugin. The problem is fixed with version 1.00.20. I just tested with my tool length sensor so far, but it worked fine. So it's time to place an order for a 3d probe ( or to build one on my own).
Steve
Re: PCB Autoleveler Plugin for UCCNC
Yes, well, switching off the VFD every time I change tool or set offsets is not a good idea. To stop and restart the VFD takes a pretty long time.
BTW, what do you mean by spindle controller? The spindle controller is the VFD. Powering off the BOB or preventing sending on/off signals in any other way is not enough safety.
Re: PCB Autoleveler Plugin for UCCNC
I added a switch to my VFD for safety purpose. he breaks the PWM signal. actually he switches to the potentiometer.
Re: PCB Autoleveler Plugin for UCCNC
Sorry, but I don't think this is a good solution. Yes, it prevents the spindle from spinning, but ONLY if the switch and VFD is working. The problem is that if the VFD flips out it can start the spindle even if the PWM pulses are blocked or the 0-10V is at 0V. The only 100% safe option is to interrupt the 3 phases going to the motor. This can be done through a relay or a manual switch. Everything else is dependent on some sort of electronics and firmware/software and that is not regarded as safe enough.
I added a switch to my VFD for safety purpose. he breaks the PWM signal. actually he switches to the potentiometer.
The above is a compilation of part of two pages from my manual, and I thought about this even before I read the relevant parts of the manual. Now, even if you say you make no mistakes (blue framed part) the red framed text is still a risk even with your switch. Of course, I have no idea how often that happens, but never the less, it can happen unless you have taken some conventional safety measures, i.e. a mechanical switch or a relay/contactor which is TOTALLY independent of any electronics and firmware and which isolates the motor from the VFD whenever necessary, which is every time I have my hands near the spindle for tool changing or any other activity, like fixing the work piece or removing the items I have just finished. I know that not everyone thinks the way I do, and many would call it over-cautiousness, but I don't mind.
Re: PCB Autoleveler Plugin for UCCNC
That is interesting BUT normally it is NOT a good idea to open teh circuit between the drive and MOTOR on an energized VFD . My vfd recomends you NOT do that as drive damages can occur. You would normally OPEN teh incoming power circuit to teh controller AND IF you needed absolute safety you would crowbar teh motor circuits to ground ( short all teh leads together and to ground) AFTER you remove power. Yo use a Break then Make type control function .
(;-) TP
Re: PCB Autoleveler Plugin for UCCNC
TP, you are wrong. The engineer in me says that if the motor is stopped then the VFD should output 0V, 0A and 0Hz, and if you disconnect the motor in that situation then NOTHING bad can happen with the VFD or the motor. That warning is meant as a warning for using such switch for on/off control. Now THAT is certainly VERY wrong. The switch is a SAFETY switch, not an emergency stop or on/off control switch.
Damages may happen if the VFD is energizing the motor and you break the current flow, otherwise not. Of course, I can not guarantee the functions of every VFD, but I doubt there is a risk unless the motor is spinning and you break the current flow. As a matter of fact, I even test run my VFD without motor for my Modbus tests. No reason for rotating the motor if it does nothing. So far I have not seen any problems caused by this, and I doubt I ever will.
In fact, I seriously doubt that there is ONE single professional mill used in industry (at least not by a serious user in Europe) which does not have this kind of safety, because it is obvious that as long as you have the VFD powered up ANYTHING can happen with the spindle, so having your hands under the spindle and in the area of operation is extremely risky unless you make it 100% sure that the spindle can not start rotating. This is valid not only for CNC machines but also for every other machine with motors. It is very normal safety procedure, which can be solved in different ways, one is to power off the VFD, another is my way, a third is to use spindle lock or other mechanical ways of preventing the motor to rotate unintentionally. Of course, I know that there are plenty people running around and not care a lot about safety, but I also know that there are plenty people without one or two fingers (or even worse) as well... I am not one of those yet, and definitely have no intentions of becoming one of those.
But... to each his own. I just commented about the risks for unintentional rotation causing damage or injury and how I prevent that from happening.
Edit:
I just opened the manual of the HY, and here is what it says regarding this:
Which is just as I said, a warning about not to use such switch as on/off, the VFD must have been commanded to stop the motor rotation PRIOR to operating that switch.
Last edited by A_Camera; 09-27-2016 at 05:07 AM.
Re: PCB Autoleveler Plugin for UCCNC
It is silly to read a recommendation of Vmaxxxx about Vfd... triying to guess what to say.
CAHIT you can for shure programm your VFD to accept EXTERNAL COMMANDS for START STOP from your input terminals on your VFD.
Normally all this VFDs have optoisolated inputs.
You can close circuit between START and Gnd and STOP and GND signal each with a relay of your BOB (or to either GND or +24V or +5V) depending of the VFD brand. This one I am attaching as example will have commons to ground, as you can see on the picture.
If you use the NO contact of your relay as START signal, then you have 100% security it will never GO ON without a REAL software command.
As an Engineer with more than 35 years experience, I agree completely with A_Camera if you disconnect a VFD at 0V in the Analog input, you expect nothing wrong will happend because it can not damage the IGBt power output stage (at 0V they go into disabled mode) BUT ! it is not recommended to go this way because you can not guarantee the VFD is receiving all the time 0 V and in this case it will not be 100% disabled.
(Except you programm an output signal of running state, and read it... etc etc.... but all this will complicate too much your goal !)
Re: PCB Autoleveler Plugin for UCCNC
A_CAMERA
in the prof. business you have always circuit braker contactors operated by charge between the motor and VFD (as you pointed out) ALLWAYS !. They will isolate the motors in case of over charges but will also work with protection devices in parallel.
This extra security layer will also fire the contactors , commanded from "security relays" like the ones from Telemecanique, Shneider, Phoenix Contact
or whatever. This is the SICK security relay prod. line, they will handle all inputs from Emergency switches, etc and isolate motor terminals from power circuits.
This is a NORM, in Europe as in many other countries.
https://www.sick.com/us/en/product-p...lays/c/g186153
this kind of devices will respond very fast ( 10 ms) .
Re: PCB Autoleveler Plugin for UCCNC
HIYA Panic still at it are you .
Re: PCB Autoleveler Plugin for UCCNC
Yes, I know that. In any case, I have NEVER seen a real industrial machine without a safety switch/circuit breaker/contactor or some other device making it 100% safe to work on the machine. I admit, I have not seen every machine on this earth, but have seen quite a few during my adult life. This is valid for EVERY machine, be that a mill, a meat grinder, elevator or whatever else you can think of. By that, it is not said that there are no pitfalls, but there is always some sort of safety involved without additional electronics/firmware/software. Can also be a pure mechanical lock, locking the motor shaft and preventing it from turning, but yes, the most common is contactors, which is OK for industry, and which I was thinking about as well, but decided not to use that solution, because I don't need the additional benefits. For me it is very convenient to flip that switch, it is placed just beside my machine in a comfortable height just where I would stand if I needed to change tool, so I will not forget flipping it.
There seems to be strong belief in that having a switch between the motor and VFD can damage the VFD. I don't know who started to spread this crap, but I suspect it is based on some misunderstanding of the cheap Chinese VFD manual with those thin, badly written manuals read by people who don't even manage to read the few pages so they just read the main head lines or the first sentences and quote those as reference. But... safety is not high on the priority list of many DIY machinists, so people take risks, some times without even knowing about them. This is especially true when it comes to electrical installations. Very few have actually any formal electrical education on this forum, most of the time it is pretty clear who has and has not. Anyway, reading a warning is one thing, understanding why is another.
Re: PCB Autoleveler Plugin for UCCNC
I was thinking about your solution again...
I added a switch to my VFD for safety purpose. he breaks the PWM signal. actually he switches to the potentiometer.
I made a quick drawing. Is your switch according to Option 1? If yes, replace it with Option 2. Option 1 leaves the input floating, which is NOT a good idea, especially if you are concerned about safety. Only Option 2 assures that the input is at 0V when the switch is activated.
...but please note, this still assumes that the VFD is working 100% reliably all the time.
Re: PCB Autoleveler Plugin for UCCNC
MY VFDs are NOT cheap chinese units and they ALL warn against it as a preventative measure (;-) AND even your cheap VFD manual warns against it.
I think you guys are confusing a safety measure to work on teh drive unit with interrupting teh ouput line of the vfd. TO work on the unit you would lockout tag out teh Power to teh VFD itself then do what you need to do then unlock and untag teh unit and return it to service.
THAT was NOT the original discussion that A_Camera started, his concern was teh safety of the operator handling an idle spindle at 0rpm. DO YOU see any of that type protective scheme to protect teh operator on a commercial CNC machine ???? NO you do not. You will see limited operator of the spindle (reduced RPM limits) and some will not allow the spindle to run IF you open the door BUT are they opening teh link between teh Drive and the motor ???? NOT in most cases.
IF you think that you need a protective device between teh VFD and teh motor DO YOU also add that protective device between teh Servo drives and teh servo Motors ??? (;-)
(;-) TP
Re: PCB Autoleveler Plugin for UCCNC
So, WHICH one is your VFD? Could you share the manual, or at least the model name? You have several, so list some of yours please, and tell us WHY they warn against it.
Sorry, I think the one who seems confused here is actually you. But the main thing is that if you put a switch between the VFD and the motor NOTHING bad can happen to your VFD as long as you don't use that switch to control the on/off the motor. Please tell us which VFD are you using. So far you sounded you had the HY and controlled it via Modbus... when you received a direct question you said you don't control it via Modbus. Now, when we discuss the HY manual, which I thought you quoted and which we discussed all the time (apart my own Rexroth) you suddenly say that you don't use that one at all, so which one are you using?
Re: PCB Autoleveler Plugin for UCCNC
I have never said I used/owned a HY vfd (;-) and I never plan to as well. I also have never said I talked to one over modbus. You may want to reread teh forum posts for clarity. IF you find where i did please share that with me.
(;-) TP
Re: PCB Autoleveler Plugin for UCCNC
Why not answer the questions and clear the confusions instead of adding to them?
Which VFDs you actually have? You have given the impression in quite a few posts that you actually have the HY, but no, you never really said that you have. You have also given the impression that you actually control the HY VFD via Modbus, which is why I asked Dan to contact you about it. I have already apologized for that mistake, so I am not going to do that again, but you could be a bit more specific when you type, it would be quite beneficial for the conversation to know what you ACTUALLY know and have, not just quoting bits and pieces from manuals, but also where that information comes from.
By saying, like you said even yesterday, this...
...you actually say "I don't have the HY VFD here, I have it somewhere else." ...or how should we interpret that? So yes, please speak clearly, say which VDDs you have. I am pretty sure that the information is relevant in this discussion and it would be appreciated by others as well.
Re: PCB Autoleveler Plugin for UCCNC
HIYA A_Camera SHOW me where I said this
"..you actually say "I don't have the HY VFD here, I have it somewhere else." .
WHY do you keep trying to put words in OTHER peoples mouths ???
I think the main problem here is English is not your first language and there is some loss of meaning in your translation.
I have been working in this field(NC,CNC,motion control) since teh fall of 1969 SO I might at least have a basic understanding of the subject. VFD brands GEES I would bet IF it was every available on this continent then I have probably used it at one point in time.
DO I speak engineer speak ?? NOPE . I use good old American redneck speak .
Re: PCB Autoleveler Plugin for UCCNC
new pcb created with UCCNC v1.2026 and the autoleveler
