Omron CQM1H-SCB41 operation manual Cleaning and Inspection

Board Replacement					Section 9-3
Serial commu-	Indicator	Status	I/O memory	Cause	Remedy
nications	display	information,
mode		etc.
Serial commu-	The COMMj	---	---	Cables are incor-	Review the wiring or
nications mode	indicators are			rectly connected.	switch settings.
is set to NT	flashing, but a			The RS-422A/485	Check whether the termi-
Link.	communica-
				port setting (2-wire	nating resistances of the
	tions error
				or 4-wire) is incor-	host computer and the last
	sometimes oc-
				rect.	node are set to ON, and
	curs in the PT.
				Adapters such as	the terminating resistances
					of other nodes are set to
				the NT-AL001-E are
					OFF.
				incorrectly wired or
				set.
				A communications	Review the wiring and
				error frequently oc-	installation environment.
				curs due to noise,	Increase the number of re-
				etc.
					tries for the PT as re-
					quired.
				The communica-	Increase the communica-
				tions monitoring	tions monitoring time for
				time for the PT is in-	the PT.
				sufficient.
				The load on the PC	Lighten the load on the
				is too high.	PC.
					Reduce the number of PTs
					connected to each serial
					port by using other ports
					for some of the PTs.
					Adjust the timeout and
					retry settings in the PT.

Note The PT serial port must be set for a 1:N NT Link. The PT will not be able to com- municate with a Serial Communications Board if the PT is set for a 1:1 NT Link.

9-3 Cleaning and Inspection

Use the cleaning and inspection methods described here for daily maintenance of the devices.

9-3-1 Cleaning

To keep the Serial Communications Board in optimum condition, regularly clean the Serial Communications Board as follows:

•Wipe the surface of the Serial Communications Board daily with a soft, dry cloth.

•If any dirt cannot be removed with a dry cloth, moisten the cloth with a mild de- tergent diluted to 2%, and squeeze out any excess moisture before wiping the Serial Communications Board.

•Do not adhere materials, such as gum, vinyl, or tape to the Serial Communica- tions Board for long periods of time. Doing so may cause stains on the device. Remove any adhered materials when cleaning the Serial Communications Board.

Note Never use benzene, paint thinner, or other volatile solvents, and do not use chemically treated cloths.

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