[Mjerica]

Hello Fadal experts,

I am forwarding this question about Fadal 6030, yr.-99
This machine works generally quite well except the cold start
procedure. Its owner described the symptons like this:

When in CS procedure, Z, and Y reference points are
found immediately and always correctly.

X-axis zero tracking seeks for some time and ends up to
error display something like "home position not found" (I don't
remember exact expression) Then, after persistent trials it
finally succeeds but may take some nerve wrecking hours. As
you may quess this machine is never intentionally shut down
(except for display). Mains power-downs happens sometimes,
usually only fraction of seconds but here we are again....
(Not to mention what this continuous power-on affects to
electronics life span, its power-on time is huge allready...?)

I asked the owner if/how he had tried starting positions
nearby indicator marks and with what result. He said there is
some marginal around indicator but it remains unclear if it
is any good to try beyond indicators close proximity. Thus
our conclution was that indicator is correctly located.
Correct...? Anyway, sometimes it ends up to find home position
which is clearly aside of indicator. The owner said, referring
to the burden of finding at least any home position, he gladly
accepts it because after that the machine work again... until
next mains glitch.

Unfortunately the history of that problem is unknown.
Only we know that it has been around by previous owner...
who "forget" to mention it until commissioning on present
owner. (He didn't shut it down either, that we know)

Are there anybody who exactly knows Fadal homing system?
The owner believes that this problem is somehow related to
linear scales equipped, some contradictional data between
encoder and linear scale? I am not convinced that the scales
have anything to do with this but do not know. I always thought
that scales belong only to the outermost servo control loop and
do not contribute to finding/defining machine reference point.

Is it simply encoder index pulse that defines home position
so that it could be (mistakenly) found anywhere within slide travel?
(periodically every ball screw revolution?)

I found this:
------------------------------------------------
Fadal Maintenance Manual
Section 16: Troubleshooting, page 531
<http://www.fadalcnc.com/media/pdf/tech_docs_1/Maintenance_Manual/Troubleshooting.pdf>

"Problem Positioning Slides to Zero

This error only occurs during Cold Start. When the Glass Slides
are not aligned close enough to the indicators during Cold Start.
Place the machine in Jog and manually align the Cold Start
indicators more accurately."
---------------------------------------------------

Does this mean that glass slides has something to do
with defining zero position? If so, does encoder index
pulse have any role after all?

Thanks for your help.

[Paul_S]

Hello Fadal experts,

I am forwarding this question about Fadal 6030, yr.-99
This machine works generally quite well except the cold start
procedure. Its owner described the symptons like this:

When in CS procedure, Z, and Y reference points are
found immediately and always correctly.

X-axis zero tracking seeks for some time and ends up to
error display something like "home position not found" (I don't
remember exact expression) Then, after persistent trials it
finally succeeds but may take some nerve wrecking hours. As
you may quess this machine is never intentionally shut down
(except for display). Mains power-downs happens sometimes,
usually only fraction of seconds but here we are again....
(Not to mention what this continuous power-on affects to
electronics life span, its power-on time is huge allready...?)

I asked the owner if/how he had tried starting positions
nearby indicator marks and with what result. He said there is
some marginal around indicator but it remains unclear if it
is any good to try beyond indicators close proximity. Thus
our conclution was that indicator is correctly located.
Correct...? Anyway, sometimes it ends up to find home position
which is clearly aside of indicator. The owner said, referring
to the burden of finding at least any home position, he gladly
accepts it because after that the machine work again... until
next mains glitch.

Unfortunately the history of that problem is unknown.
Only we know that it has been around by previous owner...
who "forget" to mention it until commissioning on present
owner. (He didn't shut it down either, that we know)

Are there anybody who exactly knows Fadal homing system?
The owner believes that this problem is somehow related to
linear scales equipped, some contradictional data between
encoder and linear scale? I am not convinced that the scales
have anything to do with this but do not know. I always thought
that scales belong only to the outermost servo control loop and
do not contribute to finding/defining machine reference point.

Is it simply encoder index pulse that defines home position
so that it could be (mistakenly) found anywhere within slide travel?
(periodically every ball screw revolution?)

I found this:
------------------------------------------------
Fadal Maintenance Manual
Section 16: Troubleshooting, page 531
<http://www.fadalcnc.com/media/pdf/tech_docs_1/Maintenance_Manual/Troubleshooting.pdf>

"Problem Positioning Slides to Zero

This error only occurs during Cold Start. When the Glass Slides
are not aligned close enough to the indicators during Cold Start.
Place the machine in Jog and manually align the Cold Start
indicators more accurately."
---------------------------------------------------

Does this mean that glass slides has something to do
with defining zero position? If so, does encoder index
pulse have any role after all?

Thanks for your help.

The machine should find the same zero within ,060 of the mark. If the machine is a little off the mark repeatedly. Move the marker to where the machine has gone. From that point on it should repeat.

[Mjerica]

Hi, Paul
The owner of the machine said he would be happy to find
at least any zero. Mostly, when a zero is finally found, sometimes
after hours of trying, it is correct.

The reason for erraneous zero might even be the
frustration of the exhausting situation. The owner said he
sometimes had begun to try seeking zero anywhere nearby indicator,
I have never been around there when this have been taking place.

[slowtwitch]

Hello, I had the same issue on my 3016. It would fault at random times locating the CS position. My Fadal has AC servos and the problem was the encoder. Thus being an AC servo, I couldn't just swap out the encoder. I replaced the the problem servo with a new one. All CS locating problems were solved

pete

[Mjerica]

@slowtwitch: "Thus being an AC servo, I couldn't just swap out the encoder.
I replaced the the problem servo with a new one."

- Hi, Pete. That is interesting. That may tell that glas slides, even if equipped,
have nothing to do with this.
What was to reason you couldn't swap just the encoder, aren't those
available separately?

For an general info.... this machine will probably have planned powerdown
in next few months because of transfer to another building. I hope i get a
chance to take a signal sample from encoder at start-up. But before that,
now at summertime, we might encounter lightning based power-downs.

[slowtwitch]

@slowtwitch: "Thus being an AC servo, I couldn't just swap out the encoder.
I replaced the the problem servo with a new one."

- Hi, Pete. That is interesting. That may tell that glas slides, even if equipped,
have nothing to do with this.
What was to reason you couldn't swap just the encoder, aren't those
available separately?

For an general info.... this machine will probably have planned powerdown
in next few months because of transfer to another building. I hope i get a
chance to take a signal sample from encoder at start-up. But before that,
now at summertime, we might encounter lightning based power-downs.

I guess the biggest issue for not replacing the encoder, was lack of information on how to do it. I'm just a lowly maintenance man who relies on youtube and these forums for info

[Mjerica]

@Pete, how did you diagnose the encoder?

[slowtwitch]

I noticed the AC servo hunting for the CS markings. When the CS finally was found (without alarming), it would be at a different location from my marked position. I tried changing the difference in the axis survey settings, but, to no avail. Again, this is an AC servo machine, so the procedure is somewhat different than with a DC servo machine.

[gaswiz69]

Fadal machines with scales do take longer to cold start. Yes, the control does use the scale as main feedback, but it also refers to the position of the encoder. If the glass scale is compromised, it will be harder for the machine to zero. Easiest way to diagnose a scale issue is to disconnect the scale before power on, then cold start. If the machine cold starts easily, look at gibs, straps, bearings, then scale. If you are going to check or adjust gibs and straps, you must disconnect the scales also, otherwise you will be fighting the scale while making your adjustments.
Hope this helps.