Mitsubishi Electronics QJ71C24/-R2, QJ71C24N, SH-080007 manual 29

1 OVERVIEW

MELSEC-Q

MELSEC		Q25HCPU	QJ71E71		QJ71C24
			RUN	ERR.
	POWER	MODE	INIT.	COM.ERR	CH1.		CH2.
		RUN	OPEN
			SD	RD
		ERR.	10BASE-T			CH1.
		USER
		BAT.
		BOOT
					RS-232
			10BASE		CH.2
					SDA
PULL					SG	2	1
		USB			SDB
					(FG)		3
					RDA	4
		RS-232			(FG)		5
			+12V		RDB	6
			12G
MITSUBISHI					RS-422		7
					/485

(d)It is necessary to create a sequence program for communication control that conforms to the external device.

(e)Communication can be performed using an user frame by registering the fixed format portion of the head and tail sections of a message as an user frame.

•When sending data, the Q series C24 adds an user frame to any data specified by the user.

•When receiving data, the Q series C24 transfers any data excluding the user frame to the PLC CPU.

	When receiving data
STX	Any data format	ETX
ETX	Any data format	STX
	When sending data

(f)It is possible to clear the current reception data without interrupting the transmission processing by using the dedicated instruction "CSET."

(3) Data communication using the bidirectional protocol

MELSEC		Q25HCPU	QJ71E71		QJ71C24
			RUN	ERR.
	POWER	MODE
			INIT.	COM.ERR	CH1.		CH2.
		RUN	OPEN
			SD	RD
		ERR.	10BASE-T			CH1.
		USER
		BAT.
		BOOT
					RS-232
			10BASE		CH.2
					SDA
PULL					SG	2	1
		USB			SDB
					(FG)		3
					RDA	4
		RS-232			(FG)		5
			+12V		RDB	6
			12G
MITSUBISHI					RS-422		7
					/485

(Details are explained in Chapter 7 and the User's Manual (Application).)

(a)In communication between PLC CPUs and communication with an external device for which transmission/receive control programming is allowed, data communication is performed in a sequence of "data transmission and response receipt".

(b)Error check of received data can be performed using the sum-check code, while the occurrence of a reception error at an external device can be checked via an ACK/NAK response.

ENQ	Data length	Any data		Sum check
				code
					ACK
Sending completed normally
			Error		NAK
Sending completed			code
abnormally

(c)ASCII code data can be used for communication using the ASCII-BIN conversion function.

QCPU			QJ71C24	ASCII
				data
	Q25HCPU		ASCII-BIN
	RUN
	MODE
	ERR.		conversion
	BOOT
	USER
	BAT.
		Binary
		data
			Binary
	USB
			data
	RS-232

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