Resetting Reference Position For Absolute Encoder
Machine: 2008 Sharp SV-2412
Control: Fanuc Oi Mate-MC
I recently had to have the servo combo unit sent off for repair. We had to disconnect the battery that stores the reference positions for the servo. A couple questions:
1. Does this battery back up anything else since its a combo unit (Power supply, spindle drive, servo drive all in one)?
2. The machine was powered down in it's zero position, does this mean I don't need to jog anything to reset the reference position?
3. Are there any other parameters I should be concerned with? I know I believe I need to reset reference position with parameter 1815, but I also heard I might have to reset 1850 (grid shift) to 0 as well?
4. Anything I need to do with spindle orientation, tool changer, etc?
Thanks!
-Max
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Well all the parameters and such are save in the CPU, which is not in the servo/spindle pack. It loads it all on power up, Mate MC is one I am not to familiar with but if it's a vertical mill, X and Y should be in the same spot but Z may have dropped at powerdown. In which case you may have to realign your tool change arm if it is an A style tool changer.
Not sure about grid shift.
Re: Resetting Reference Position For Absolute Encoder
I found a good article on a fadal website that explains the procedure I will need to do:
https://www.fadalcnc.com/media/pdf/F..._Procedure.pdf
If you have a Fadal machining center with the Fanuc Oi-M or 18i control, you will need to make
sure you replace the axis backup batteries. If they go low, you will first get a LOW BAT alarm for
days before they actually become so low that you lose your position data. This is the information
stored in each motor's encoder of the zero return position. Unlike some of the other machine
configurations where you have limit switches to set the machine home, Fadal uses software
limits and position the table in mid travel as the zero position...other than the Z axis.
Try to jog your axes all to the cold start positions, but if you cannot, proceed below.
If your batteries have gone low and you've lost your zero position, getting yourself back to zero
is very easy. Here are the steps:
1. Navigate to the parameter lock. (See Figure 1)
2. Change it from a zero to a one. You will get thrown to an alarm page. No worries. (See
Figure 2)
3. Press the SYSTEM hard key and navigate to parameter 1815 (See Figure 3). Start with the
X axis. Use the arrow key to move to the right until you are at the APZ column (See
Figure 4). Change this from a zero to a 1. You will be thrown to the alarm page and
prompted to turn the power off and back on (See Figure 5). Comply. When the machine
powers back up, you should be able to move the X axis. Jog it to the center of travel.
Navigate back to parameter 1815 and turn the X APZ bit to zero again. This will throw you
to the alarm page again. No worries, power down and back up.
4. Go back to parameter 1815 and change the X APZ bit back to a 1. This now set the zero
return position.
Now perform this procedure for the Y and Z axis.
Here is what you are doing: When the parameter 1815 APZ column changes to a zero, this
means the absolute encoder in the respective axis has lost its zero position. When you turn it
back to a 1, this enables you to move the axis back to zero if it is not. You must then change it
back to a zero to release the old zero position which you randomly set to move the axis, then
back to a 1 to set it in its correct position.
The Z axis is tricky because you must set it perfectly or your tool change position will be off. If it
is not correct, continue to use this procedure as you move the zero to adjust until you have your
tool change position set properly and can do smooth tool changes.
When you are finally done, change your parameter lock back to a zero and cycle the power one
more time.
You are done!
I think the problem I will need to watch for is the tool change height. Hopefully I can call up a G30, manually move the tool changer over and see if it lines up. If not, I think I need to follow this procedure:
1. Place an empty tool holder in the Tool Change Pot that is in the Tool Change Ready position, one having an end face that will allow easy measurement of the distance from table to end face, or table to the underside of the Tool Change Ring.
2. Measure the distance from the machine table to the selected Tool Holder surface with a height gauge, or whatever suitable measuring equipment that's available. Note this measurement.
3. Place the same Tool Holder as used in point 2 in the spindle of the machine.
4. Perform the G91 G30 Z0.000 command and then repeat the measuring exercise used in step 2 above on the Tool Holder currently held in the spindle. Note this measurement.
5. Compare the measurements gained in steps 2 and 4 above. The difference between the two is the amount the G30 position will have to be moved.
6. The G30 position is set via parameter as an Incremental Distance from the Reference Return Position of the respective axis.
Re: Resetting Reference Position For Absolute Encoder
Ok I finally have everything good to go. I'll add some notes just in case someone stumbles upon this thread through a google search in the future.
I called Sharp (who were very accessible over the phone) and asked about the zero referencing procedure. The procedure is similar to what I pasted above, but here's what I did.
1) Power Up
2) Switch to MDI Mode
3) Hit offset key twice and change Parameter Write Enable from 0 to 1
4) Hit feed hold button to silence the parameter write alarm
5) Hit System Key, should bring you to the parameter page by default
6) Type 1815 and hit the "No. SRH" soft key (number search) should bring you to Parameter 1815
7) There will be a row for each axis (xyz) and under the APZ column, change from 1 to 0 for one of the axis.
8) It should automatically bring you to the message screen, telling you to power off (go ahead and power off and wait 15 seconds)
9) Power back up, Alarm should sound (silence with feed hold button) switch from MDI to hand jog and jog the axis along its travel.
10) After you've jogged back and forth for several inches, jog toward the zero reference alignment mark, slightly pass the alignment mark (but don't go more than an inch beyond or you will overtravel)
11) Bring it back until the alignment marks match (just eyeball this)
12) Switch back to MDI mode and go back into SYSTEM>PARAM> 1815 and change the APZ back to 1
13) It should ask you to power off again. Power Back up and repeat steps again for the other two axis (if needed)
Tool Changer Alignment:
1) Power up and zero return, switch to handle jog
2) Manually load toolholder into spindle
3) Switch to MDI, Rapid override to 25%, Make sure you're ready to hit E-Stop in case some weird **** happens next, then Call up an M30 Z.0.0 then on the next block call up an M6 tool change (but don't specify tool) then cycle start. This should bring the spindle to what the control thinks is the tool change height.
4) Find your favorite way to measure the height of the face of the toolholder (not the tool) to the table or other known surface. I used a magnetic base indicator and set it up against the face of the toolholder, noting it's position, then I hand jogged over to a tool in the magazine (pulling the needle of the indicator down to clear the sheet metal housing) and let the indicator rest up against the face of an identical Cat40 toolholder. I noted the difference between the two (in my case, it was about .061" higher than the toolholder I measured on the spindle, meaning the spindle was a little too low)
5)Switch back to MDI mode, SYSTEM>PARAM>1241 Parameter 1241 "REF. POINT #2" this is your stored tool change height for the Sharp SV-2412. It should be a large number, mine was -125000. This number represents how far in inches down from Z axis zero reference point your spindle is when it initiates a toolchange multiplied by 25,400
6) I took that value (which for me was -125000) and divided it by 25,400 and got -4.9212598425 inches. I then added the difference I needed to compensate from what I measured with the indicator earlier (which for me was .061) and got -4.8602598425 which I then multiplied by 25,400 getting -123450.6
7) I changed the 1241 "REF. POINT #2" parameter from -125000 to -123450 (I left off the .6 in case that could have caused a problem)
8) Rebooted for prudence. Zero Return All Axis, then went into MDI and did another M6 without tool to confirm the new tool change height passed the eye test, then I called up an actual tool change (while being ready to hit E Stop in case **** happened)
All finished! Hope this helps. Here's some photos:
Re: Resetting Reference Position For Absolute Encoder
I see you have a job setup on the machine. One way to see if your new ref point is the same as before is to compare a known good tool length offset from before the ref point was lost. if they are different then I try again. This only applies if there has been no mechanical changes. There is no ref return mode on that machine?
Re: Resetting Reference Position For Absolute Encoder
Thank you, this saved my ass this morning.Originally Posted by MaxWeber
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