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Dialog 4 Error Code 14

Rider-83

Aluminum
Joined
Nov 20, 2005
Location
England
I've found an issue with my Z axis. (After fifteen years!)

It appears we don't have all the 450mm of Z-Axis travel. I noticed the limit switch cam plate looked different than the others, and in fact someone has made a slightly longer version to stop the Z-axis using the last 79mm of travel.
When I remove it, the error message 'Code 14' appears, indicating a problem with the LS904 scale.
Since this area of travel is very rarely used on the machine, it has therefor never been noticed. But, I now have a job where I need all of the 450mm.
I have had the scale professionally examined, and other than a weak reading from the scale 'head' there are no serious issues revealing themselves. I have been informed that the issue he found with the 'head' would if anything stop the scale working completely, but not in the specific area we have the issue.
I can have the scale head refurbished, but this still may not cure the 'black spot' area.

Any ideas?
 
First note:
There are two limit stop cams that Deckel used on that machine.
The shorter travel version was used when the universal table was fitted.
The 2038 table is taller and the extra height is needed to allow the top to rotate over the "X" slide...The short travel cam is used for safety...

There is a companion part that is also fitted when the 2038 table is fitted..It is an extended hard stop that physically limits the travel.....

Need to be sure that your machine is not fitted with this stop.
Be sure that you have free travel to the top of the slide (hand wheel)
If not check to be sure the hard limit is not fitted....

Sorry i don't have my FP4NC book here to show the location of the stop.
If you look under the "Z" slide on the side away form the operator, nested between the raised portions of the box way...there are two cap screws that secure a plate between then.
That plate carries the stop block which sits vertical in a pocket.

Other than that...I would have the scale cleaned by a competent service agency (Heidenhain) or do so your self....Some instructions on this board nicely done by Bruce...
But my suspicion is that the scale is working well enough....generally problems reading the scale result in an error indicator showing the letter "V" to the right of the axis numerical display.....

Might try swapping the axis cards...(be sure to set the DIP switches) Doubt this will make any difference.....

Cheers Ross



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Ross,

Regardless of the stops (I removed it, carefully), the machine wont travel the full 450mm because there is an error in the scale. It simpley stops 79mm short becase of a Error Code 14.
The Heidenhain engineer has run tests on the scale, and cannot find any errors to cause and individual positioning error. Only that what he found may cause complete error over the full range. Which in my case isn't happening.
It has since been suggested that the scale wasn't fitted parallel to the axis, and may be pulling the head when it reaches its furthest extreme.
 
If you set the machine to run using the hand wheels, and advance above the stop point by hand does the display still read correctly?
And will it return to the same point when going back down (set an indicator to verify)

Not seen this fault and as i said before, the machine should show an error on the axis display if the scale is being cranky....
Scale alignment is set by the machine....you just seat the ends of the spar against the machined pads on the casting and the scale is aligned....
Only other setting is to set the gap between the read head outer part to the scale body. Should be set at .040" (1mm) ...I use two feeler gauges one top one bottom so that things are parallel...

Cheers Ross

Additional thoughts....Would first be sure the Tach comm is clean...Yea i know the scale is the issue...but the error code says that its a "Contour" error...suggests that the scale and the slide velocity are not happy....
Would also be sure to adjust the "Tach" and drift on your Bosch cards before going too far...
 
Tach and drift are fine. I've already gone through that .
However, trying to wind past the point in 'hand' . I thought about that as well, I shall give it a try but I need to wait for the scale to come back from the specialist.
Should be interesting to see what we get back from the measuring system, right?

Ta,
Nick,
 
I been told recently by a Deckel engineer that there may be a 'soft limit' parameter set on the system to prevent the machine from passing over the limit point.
Im not sure if this is actually true, as the system doesn't use absolute referancing.

Can any one help here?
 
Don't think the engineer is correct!
All the FP-NC's use limit switches on cams to set the rapid feed ramp down, the limit of the slide and the over travel.
There are three cams and three switches for each axis in each direction....Lots of bother if there are soft limits as well....And as you say there are no absolute encoders
on the machine, so how would the control keep track of where it was relative to a soft limit.....
There is a hard "Home" location , but that is a physical file marker on the scale,being accessed through movement when engaged in mode 3, stopping the feed and setting the display to "0.0000"


Cheers Ross
 
Been 4 months since this original post....did you get the scale back from being serviced?
Did you try the test i describe above where you move the slide past the stop point using the hand wheels, and then return to see if the position
counts past and returns?

Strange fault, i am curious to learn its real cause.

Just as a point of reference, you did not say which direction you were loosing travel....Am assuming it is in the "Z Plus" but i could be wrong.

Cheers Ross
 
I'm having the Scale refurbished while it is out of the machine. Should get it back in around two weeks.

The Deckel engineer knows my machine from the original buyer back in '86, and it was fitted with the Z-Axis bellows. When used in conjunction with the NC500 there is a possibility the crush the bellows when at the mininum z-axis limit, therefor Deckel fit a longer limit switch cam & a differant DIL switch configuration in the controller. He will give me the new DIL settings when back at the workshop (Hopefully very soon)..
 
Well Ross,

All is now good!
Machine is now working with the full 450mm of Z travel.
Absolutaly nothing to do with DIL switch settings (I was always doubtfull this was the reason, mainly because its not an Absolute system).
The Z scale came back from refurbishment and worked perfectly.
I've had my doubts about the Deckel engineer for some time due to some other issues (Some very serious).
There was obiously a bad patch on the scale, and the previous owners have made a special longer 'limit cam', of which looks completly differant than the Deckel supplied items.

Happy Days!!!
 
Good news!
Do i have this correct? The previous owners had an issue with a dirty scale, and made a longer limit switch to keep the travels form getting to the problem area?
Maybe the previous owners had some fixturing on the machine and the longer switch cam was done to prevent a possible crash...
So in reality the modified hard limit switch was stopping the movement short of full travel....

Glad you get it sorted....
Cheers Ross
 








 
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