Omron Programmable Terminals NT31 NT31C - Manual (Page 250)

7-2 Section Responding to Displayed Error Messages
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Example:
Parity error at serial port A
Receive Errors
The following errors can occur when receiving data.
• Parity error
• Framing error
• Overrun error
• FCS (sum value) error
• Time out error
• Data over flow error
• PC unit No. error (host link only)
• NAK received (in the case of the host link, the end code is also displayed)
• Undefined command error
Send Errors
The following errors can occur when receiving data.
• Time out error
• Data over flow error
The remedies to take in accordance with the displayed cause are indicated in the
table below.
Error Details Displayed Probable Cause Remedy
Parity Error
Framing Error
Over-run Error
Communication parameters/
conditions set incorrectly. Check if the settings at the host for parity bit, frame
length, communications speed, stop bit length and
flow control agree with those at the NT31/NT31C.
Over-run Error
The connecting cables are not
connected correctly. Check the communication cable connection and
perform a conductivity test. If there is a fault,
replace the cable. For details on communication
cables, refer to Section 4 Connecting to the Host
from the RS-232C Port, and Section 5 Connecting
to the Host from the RS-422A/485 Port.
Noise caused data corruption during
communication. Carry out grounding work in accordance with the
conditions by referring to 3-1-4 Grounding, page 34.
FCS (Check Sum) Error Noise caused data corruption during
communication. Carry out grounding work in accordance with the
conditions by referring to 3-1-4 Grounding, page 34.
The PC is transmitting incorrect
data. Check the operation at the host side.
Probable Causes and
Remedies