Omron C200HW-CLK21, CVM1-CLK21, CS1W-RPT01, CJ1W-CLK21-V1, CQM1H-CLK21, CS1W-CLK21-V1 Introduction

IntroductionSection 6-1

6-1	Introduction
			A message service is a command/response system used for data transmis-
			sion between nodes on a network, i.e., PLC to PLC, PLC to computer, and
			computer to PLC). The message service can also be used to control opera-
			tions, such as mode changes. The message service is implemented by send-
			ing commands from the user program. The following communications
			instructions are used:
			SEND and RECV: Instructions for sending and receiving data.
			CMND: An instruction for sending FINS commands. Some FINS commands
			are supported by Controller Link Units, and other FINS commands supported
			by the PLC’s CPU Unit.
Message service			SEND/RECV instructions			CMND instruction (FINS commands)
Source		PLC to PLC	C200HX/HG/HE,	C200HX/HG/HE,		CS/CJ-series, CVM1,
node to			CS/CJ-series, CVM1, CS/CJ-series, CVM1,			CV-series, or			C200HX/HG/HE,
destination
			CV-series, or	CV-series, or		CQM1H-series PLC			CS/CJ-series, CVM1,
node			CQM1H-series PLC	CQM1H-series PLC		(Not supported by the			CV-series, or
					(Com-	C200HX/HG/HE.)			CQM1H-series PLC
					mand for					(Com-
					CPU Unit)					mand for
										Controller
										Link Unit)
			SEND				Command
						CMND				(Com-
										mand for
			User program			User program				CPU Unit)
			A program is not required for receiving					Command
			responses when the PLC executes			A program is not required for receiving
			SEND and RECV.
						responses when the PLC executes
						commands.
		PLC to	C200HX/HG/HE,
		computer
			CS/CJ-series, CVM1,
			CV-series, or CQM1H- Computer
			series PLC

	Command		A program is required for sending and
SEND			receiving data with the computer.
			A program is not required for receiving
			responses when the PLC executes commands.
Computer			C200HX/HG/HE,
to PLC		Computer
			CS/CJ-series, CVM1, CV-series
(The equivalent of SEND/			or CQM1H-series PLC
				(Command for
RECV and CMND are sent
from the computer pro				Controller Link
				Unit or CPU
gram.)
				Unit)

Command

Programming is required to receive responses at the computer.

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