Loss And Restoration Of Absolute Position Data - Mitsubishi Electric C70 Setup Manual

4.2.1.1 Loss and Restoration of Absolute Position Data

(1) Loss of Absolute Position Data
Any of the followings may result in the loss of absolute position data.
- Changing a parameter related to absolute position.
- Writing a parameter which was acquired when the zero point was in a different position.
- NC: SRAM clear
- NC: low battery
- Failure in NC absolute position data
- Servo drive: low battery or uninstallation of the battery
- Servo drive: disconnection of detector cable
The absolute position data can be restored by Backup/Restore or SRAM data.
(2) Restoration by Backup/Restore
- Execute "Restore" with Backup/Restore.
- Turn the NC power OFF and ON.
Restoration with the GOT's Backup/Restore function restores the linear axis, but not the rotary axis. An initialization
of the absolute position of the rotary axis must be performed.
The same restoration as the Backup/Restore function can be performed by writing the parameter (ALL.PRM).
Status at Restore
Linear axis
Rotary axis
It is dangerous to restore the backup data of other machine when the absolute position is
established because the zero point will be established with the absolute position of the linear
CAUTION
axis rewritten, thus the zero point position is off the right position.
Initialize the zero point again.
(3) Restoration by SRAM data
- On the CNC monitor, go to [PLC-I/F] screen from [DIAGN IN/OUT], and set "SM69" to "Device", "1" to "Data" and
"2" to "Mode".
- Select [Maintenance] of CNC data I/O, copy the backup SRAM.BIN to the NC.
Turn the NC power OFF and ON.
Restoration by SRAM data is available only if the rotary axis motor has not rotated in a same
direction 30,000 times or more since the acquisition of the data.
Otherwise, the zero point of the rotary axis will change by turning the power OFF and ON after
CAUTION
writing the SRAM data, which will cause danger. Make sure the zero point is not off the right
position.
The use of this method should be limited to when necessary, such as when replacing an NC
unit, and requires enough safety confirmation before executing.
(Note) If "Z70 Abs posn error 0101" occurs, execute SRAM clear and data restoration or initialize the zero point.
4.2 Initializing CNC CPU Internal Data (Clearing SRAM Data)
Absolute position established
- Status will not change
- Absolute position internal data will be
updated
- Status will not change
- Absolute position internal data will not be updated
Absolute position not established,
SRAM clear
- Absolute position will be established
- Absolute position internal data will be
updated
C70 Setup Manual
79