Omron NT11 - 01-2004 User Manual page 154

Responding to Displayed Error Messages
Probable Causes and
Remedies
Error Details
Parity Error
Framing Error
Over-run Error
FCS (Check Sum) Error
Time-out Error
NAK received
Undefined Command Error The host is not supported.
• Framing error
• Overrun error
• FCS (sum value) error
• Time out error
• Data over flow error
• PLC unit number 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.
Displayed Probable Cause
Communication parameters/
conditions set incorrectly.
The connecting cables are not con-
nected correctly.
Noise caused data corruption during
communication.
Noise caused data corruption during
communication.
The PLC is transmitting incorrect
data.
The connecting cables are not con-
nected correctly. (Send/Receive)
The communication service of the
host is stopped. (Send/Receive)
Time-out Interval is too short. (Send)
---
Command level 3 is not effective.
Remedy
Check if the settings at the host for parity bit, frame
length, baud rate, stop bit length and flow control
agree with those at the NT11.
Check the communication cable connection and per-
form a conductivity test. If there is a fault, replace the
cable. For details on communication cables, refer to
SECTION 2 Hardware Settings and Connections,
and 2-5 Connection to a PLC by the Host Link (RS-
422A Type).
Carry out grounding work in accordance with the
conditions by referring to 2-2-3 Wiring the Ground
Wire, page 21.
Carry out grounding work in accordance with the
conditions by referring to 2-2-3 Wiring the Ground
Wire, page 21.
Check the operation at the host side.
Check the communication cable connection and per-
form a conductivity test. If there is a fault, replace the
cable. For details on communication cables, refer to
SECTION 2 Hardware Settings and Connections,
and 2-5 Connection to a PLC by the Host Link (RS-
422A Type).
Check that the host is capable of communicating with
the NT11 (confirm that the communication settings of
the host and NT11 match, and connection between
the host and NT11 if flow control is set).
Set a longer value for Time-out Interval at the host
side.
Check the settings for allocated words and bits.
If noise is a possible factor, distance the cable from
sources of noise and insert a noise filter in the power
supply line.
If using the equipment in a location subject to a lot of
noise, use a cable with a high degree of protection
against noise for the transmission route. Also make
the cable as short as possible.
Check the PLC model used for the host.
Check that the command level setting for the host is
level 1, 2, 3.
Section 6-2
141