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Replacing the encoder battery unit

MOTOMAN absolute encoders keep their position data using a battery unit mounted on the manipulator. On the MH50 II series, the battery unit is inside the connector base at the back of the robot. Replace it when a battery alarm appears on the controller.

Replacement procedure (MH50 II example)​

  1. Turn off the controller power.
  2. Remove the connector base plate and pull out the battery unit.
  3. Take the battery out of its holder.
  4. Connect the new battery unit to the free connector on the board.
  5. Only then disconnect the old battery unit from the board.
  6. Fit the new battery into the holder.
  7. Fix the plate with its bolts, taking care not to pinch any cables.

The order of steps 4 and 5 is what matters. Always connect the new one before disconnecting the old one, so that the encoder data is not lost.

When you need to disconnect a motor's encoder connector​

Disconnecting a motor's encoder (detector) connector, for example to replace a motor or check wiring, erases that motor's home position data. Before disconnecting it, connect a temporary battery unit as follows:

  1. Remove the cap from the battery backup connector at the end of the motor (marked BAT and OBT).
  2. Connect a temporary battery unit there.
  3. Disconnect the encoder connector and do the work in this state.
  4. When the work is finished, check that every connector is connected, then remove the temporary battery unit and refit the cap.

Do not remove the permanent battery unit in the connector base during this work.

If the data is lost anyway, see Home position calibration.

Source: Based on YASKAWA manual HW1482733.