Originally Posted by
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.