Upc Battery & Zero Return

[Jedi]

Im running a 6 axis Hanhwa screw machine and the upc battery died completely. The zero return alarms are apearing. In the manuals it doesnt show how to zero return and theres no zero return when you start the machine because the battery stores it. The controller is a Fanuc 18i. Also is there any tips for recharging the batteries because it says to use lithiium D batteries that are not rechargeable so they have to be replaced once a year.

[HuFlungDung]

FWIW, my limited experience with a Mitsubishi cnc, would be that there are options in the parameters to set the method of zero return. In the case of a battery backup, I believe the machine would be using absolute position, which means that the encoders are kept alive enough to monitor position even when the machine is powered down.

If the battery dies, then the absolute position is lost. At that point, then I would have to switch the zero return method to one of the other methods, such as "dog return" (limit switch + encoder index) or "bumper stop" (turn the motor current limit way down, and then gently run the axis to a fixed bumper until the current limit is reached). You may have to change the zero return method, power down and power back up to begin the zero return in the new temporary mode.

When the machine indicates by one of these other methods that it has set a home position, then the mode of zero return is changed back to absolute, the machine powered down and powered back up, and if the new battery is in place and working, then it should retain the return positions that were just set.

The original manufacturer had to use some sort of external system to set the zero return reference points. It may be a bit of intelligent guessing to figure out how it was done. It may also be necessary to install, via parameter adjustment, exactly what the defined position should be at the moment of zero return. For example, machine zero on the X axis of a lathe would likely be the tool change position, so a person may wish to define the tool home with an actual X axis value representing the position of the reference on the turret.