[ElManco]

Hello guys,

A short word to introduce myself: I'm 27yo, mechanical engineer and very new in the world of CNC.
I recently acquired an old CNC, Hardinge Cobra 42 with a Fanuc 21T controller but the battery went flat (the CNC didn't move in nearly 10 years...) so ofc I lost the axis reference (fortunatly not the machine parameters!!)
I tried to do a little research by myself to reset everything but I'm hitting a wall

I count on your help to get me out and enjoy this lathe

What should be the 1st step: resetting the home position? or resetting the 0-reference? (or it's the same thing and I didn't understand sh**...)
So, I read a lot about setting APC and APZ to 0 and back to 1 etc.. but my question is, what am I doing? what does this APC/APZ bit do?

I'm now familiar with menus and some settings but the whole meaning is still not clear ?_? I guess I'm missing the point and doing the steps wrong...
Would someone be so kind to try and explain it to me?


Thanks a lot, hope you find some time to guide me
Cheers

[Mike283]

APC tells the control that the servo motor(s) have Absolute Pulse Coders.

APZ is a flag that indicates that the reference position is known.

If APZ is 0 you get a 300 alarm indicating that you must re-establish the reference position. You can move the axis to the place you want the reference position to be and set APZ to 1 then cycle power.

If you get an alarm that says it's impossible to set the reference position you'll need to move the servo motor at least one full revolution and cycle power before setting APZ.

WARNING: The reference position must be set properly because all stroke limits are based on the reference position.

Hope this helps!!

[STLMachinist]

if you have a hard copy of parameters, see if APC/APZ are set in there. If they are not, then do not worry about those. Easiest way to tell is, put machine in "REF" mode, and jog axis towards + direction, if it moves quickly, then slows down and stops with no alarms, then these parameters do not need to be set and can be set to 0. If it overtravels, then APC for each axis needs to be set to 1. See below:

APC means that the control uses an absolute position for its reference/home position. (Yes, they are the same thing in most cases) (Parameter 1815.5)
APZ tells you if this position is known by the control. (Parameter 1815.4)

To set home position, move axis to home location, and set APZ(1815.4) or each axis. This position is normally specified by Hardinge. Unfortunately, I don't know where this position is. But, it is normally pretty close to the end of the travel in the + direction.

Hope this helps!

[ElManco]

Hello guys,
thanks a lot for your reply, I have a better understanding of the way of doing. My mistake was to think that these bits were for locking the value. In a way it does but it also enable writting after a power cylce.
My control does have APC. You said that home and reference are often the same, for me it seems that home position is where the turret stands during her free time and the reference is the very center of the rotating part.
Is it possible or am I mistaken and confusing things again?

Now I have a rough position but I think it's ok for a start. (by the way how would you adjust for the best this? I was thinking of machining a piece of metal and measuring it to see the deviation and correct it)
have a good day!

[zavateandu]

to set the refernce position is a simple way:you have to look in the back of the machine(for the Z axes) where are the giudeways and you must see a hard limit dog that will touch a limit switch,that will be the emergency limit if the axes will not stop during reference and is a risk for escape from guideways or pull out the covers from support,so that hard limit is a MUST.
you need to have a soft limit after reference and a hard limit after soft limit like in the drawing.

many machines will not have the hard limit with limit switch and will use a mechanical stopper such as hard rubber or so.

[ElManco]

Hello guys!
Thanks a lot for your help!! I now have set references and I'm preparing to code my first program!
Any help/advice is more than welcome, especially given the fact that the documentation is very poor regarding amateur-user... :S
I tried to use a simulator (CNC Simulator) but undortunatly it doesn't have all the special code I have on the CNC (for instance G90)
Any other is working with Fanuc special code?
Have a good day, and see you soon

[ElManco]

Hello,
one quick question about reference; I put the turret on the X-axis, perfectly to 0 but I am still 0.1 mm out on the "Y-axis" (perpendicular to X). I've been told that there is an electronic parameter to set this axis, could you confirm and tell what it is? or tell me how to change this?
Thanks a lot!
byebye

[bilal7619344]

Dear Sir,
I bought a Cobra 42 with 21I-TA, I lost parameters of that due to battery fail. Could you please help me?
Email: [email protected]

[bilal7619344]

Dear Sir,
I bought a Cobra 42 with 21I-TA, I lost parameters of that due to battery fail. Could you please help me?
Email: [email protected]