Mitsubishi Electronics manual 161

11 TROUBLESHOOTING

MELSEC-Q

Special Relay List (Continued)

Number	Name	Meaning	Explanation	Set by	Corresponding	Applicable
				(When Set)	ACPU	CPU
					M9
SM250	Max. loaded I/O	OFF: Ignored	• When this relay goes from OFF to ON, maximum loaded	U	New	+Rem
	read	ON : Read	I/O number is read to SD250.
			• After the head I/O number of the I/O module being
			replaced is set in SD251 is set, on-line I/O module
			replace ment is enabled when this relay is ON.
			(Only one module can be replaced at each setting.)			Q2A (S1)
SM251	I/O change flag	OFF: No replacement	• To replace an I/O module in the RUN status, use the	U (END)	M9094
		ON : Replacement	program or a peripheral device to turn this relay ON; to			Q3A
			replace an I/O module in the STOP status, turn this relay			Q4A
			ON in the test mode of a peripheral device.			Q4AR
			• Do not switch between RUN and STOP status until I/O
			module replacement is completed.
SM252	I/O change OK	OFF: Replacement prohibited	• Goes ON when I/O replacement is OK.	S (END)	New
		ON : Replacement enabled
			• Effective for the batch refresh
SM254	All stations	OFF: Refresh arrival station	(also effective for the low speed cyclic)	U (Every	New	QCPU
	refresh command	ON : Refresh all stations	• Designate whether to receive arrival stations only or to	END)
			receive all slave stations.
		OFF: Operative network	• Goes ON for standby network
SM255			(If no designation has been made concerning active or	S (Initial)	New
		ON : Standby network
	MELSECNET/10		standby, active is assumed.)
SM256	module 1	OFF: Reads	• For refresh from link to CPU (B, W, etc.) indicate whether	U	New
	information	ON : Does not read	to read from the link module.
SM257		OFF: Writes	• For refresh from CPU to link (B, W, etc.), designate	U	New
		ON : Does not write	whether to write to the link module.
		OFF: Operative network	• Goes ON for standby network
SM260			(If no designation has been made concerning active or	S (Initial)	New
		ON : Standby network
	MELSECNET/10		standby, active is assumed.)
SM261	module 2	OFF: Reads	• For refresh from link to CPU (B, W, etc.) indicate whether	U	New
	information	ON : Does not read	to read from the link module.
SM262		OFF: Writes	• For refresh from CPU to link (B, W, etc.), designate	U	New
		ON : Does not write	whether to write to the link module.
		OFF: Operative network	• Goes ON for standby network
SM265			(If no designation has been made concerning active or	S (Initial)	New
		ON : Standby network
	MELSECNET/10		standby, active is assumed.)
SM266	module 3	OFF: Reads	• For refresh from link to CPU (B, W, etc.) indicate whether	U	New
	information	ON : Does not read	to read from the link module.
SM267		OFF: Writes	• For refresh from CPU to link (B, W, etc.), designate	U	New
		ON : Does not write	whether to write to the link module.
		OFF: Operative network	• Goes ON for standby network
SM270			(If no designation has been made concerning active or	S (Initial)	New
		ON : Standby network
	MELSECNET/10		standby, active is assumed.)
SM271	module 4	OFF: Reads	• For refresh from link to CPU (B, W, etc.) indicate whether	U	New
	information	ON : Does not read	to read from the link module.
SM272		OFF: Writes	• For refresh from CPU to link (B, W, etc.), designate	U	New
		ON : Does not write	whether to write to the link module.
			• Goes ON when a CC-Link error is detected in any of the	S (Status		QCPU
			installed QJ61QBT11.		New
				change)		Remote
SM280	CC-Link error	OFF: Normal	Goes OFF when normal operation is restored.
		ON : Error	• Goes ON when a CC-Link error is detected in any of the
			installed A(1S)J61QBT11.	S (Error)	New	QnA
			Stays ON even after normal operation is restored.
SM320	Presence/absenc	OFF: SFC program absent	• ON if SFC program is correctly registered, and OFF if not	S (Initial)	M9100
	e of SFC	ON : SFC program present	registered.
	program		• Goes OFF if SFC dedicated instruction is not correct.
			• Initial value is set at the same value as SM320.
			(Goes ON automatically if SFC program is present.)
			• SFC program will not execute if this goes OFF prior to
SM321	Start/stop SFC	OFF: SFC program stop	SFC program processing	S (Initial)	M9101
	program	ON : SFC program start	• Starts SFC program when this relay goes from OFF to	U	format change
			ON.
			• Stops SFC program when this relay goes from ON to
			OFF.

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