Omron NT631C manual Probable Causes and Remedies, Send Errors

Responding to Displayed Error Messages Section 7-2

Probable Causes and Remedies

•Overrun error

•FCS (sum value) error

•Time out error

•Data over flow error

•PLC unit No. error (Host Link only)

•NAK received (in the case of the Host Link, the end code is also dis- played)

•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	Communications parameters/	Check if the settings at the host for parity bit, frame
Framing Error	conditions set incorrectly.	length, communications speed, stop bit length and
		flow control agree with those at the NT631/NT631C.
Over-run Error
	The connecting cables are not con-	Check the communications cable connection and
	nected correctly.	perform a conductivity test. If there is a fault, replace
		the cable. For details on communications 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	Carry out grounding work in accordance with the
	communications.	conditions by referring to 3-1-4 Grounding, page 34.
FCS (Check Sum) Error	Noise caused data corruption during	Carry out grounding work in accordance with the
	communications.	conditions by referring to 3-1-4 Grounding, page 34.
	The PLC is transmitting incorrect	Check the operation at the host side.
	data.
Time-out Error	The connecting cables are not con-	Check the communications cable connection and
	nected correctly. (Send/Receive)	perform a conductivity test. If there is a fault, replace
		the cable. For details on communications 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.
	The communications service of the	Check that the host is capable of communicating with
	host is stopped. (Send/Receive)	the NT631/NT631C (confirm that the communica-
		tions settings of the host and NT631/NT631C match).
	Time-out Interval is too short. (Send)	Set a longer value for Time-out Interval at the host
		side.
	Time-out Interval is too short.	Set a longer value for Time-out Interval in the System
	(Receive)	Menu. (6-9-12 Setting the Time-out Interval,
		page 181) It may also be possible to solve the prob-
		lem by shortening the host cycle time.
PLC Unit No. Error	The unit # does not match that set on	Re-set the unit number at the host side to 0.
	the PLC.
	Noise caused data corruption during	Carry out grounding work in accordance with the
	communications.	conditions by referring to 3-1-4 Grounding, page 34.

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