Omron NT20S Operation Manual page 257

Responding to Displayed Error Messages
238
Some error messages are displayed even if the "Automatic Reset" memory switch
is set.
S Procedure when a communication error occurs
When an error message is displayed, press the [EXIT] touch switch displayed on
the screen. The screen display will return to the RUN mode.
S Display of communication errors
As shown below, communication errors are displayed in the center of the screen,
together with a classification indicating whether they are receive or send errors.
[Screen when an error has occurred during reception]
RECEIVING ERROR
EXIT
[Screen when an error has occurred during sending]
SENDING ERROR
EXIT
<Error Description>
Parity Error
Overrun Error
Overflow Error
Framing Error
Buffer Overflow
Time Out
NAK Received
Unit No. Error
FCS Error
<Type of error>
Time Out
Section 7-2