An RS-232 data transmission error (such as character overrun) has occurred on the APC to SMP400 communication line.
What you should do:
To clear the error, click Clear error in the XYZ Display window.
To clear it using an RCU-II, press and hold down the Servo Power Off button and then press the Joy button twice.
If the error reoccurs, contact your Giddings & Lewis service representative.