Omron NT31 Operation Manuals page 245

System Maintenance
Reference
Checking the Battery Voltage
234
To end the check, press the touch switch at the top right corner (NT31: displayed in
reverse video; NT31C: displayed in yellow). The NT31/NT31C will return to the
"DEVICE CHECK MENU".
- The functions of touch switches pressed during the I/O check are not notified to
the host.
- The check cannot be performed until the touch switch at the top right corner is
displayed in reverse video (for NT31) or displayed in yellow (NT31C). Start the
check after the status of the touch switch at the top right corner has changed.
Check the voltage of the NT31/NT31C's built-in battery by following the menu op-
eration from the System Menu shown below.
Select "Touch Switch".
Press the touch switches displayed on the
screen. A touch switch is normal if it is dis-
played in reverse video while pressed.
Select "Maintenance Mode".
Section 6-11