7-39
·A DSR message can include variables to set data in the I/O memory (such as data
memory) of the CPU Unit or write response data to the I/O memory.
·EachcomponentofamessageisinthememoryoftheCommunicationsBoard.There-
fore, the CPU Unit canjust executethe PMCRinstruction tosend orreceive thedata.
Therefore,thereisnoneed to write ladder programsforthecommunicationsprotocol.
CPU Unit
PMCR
instruction
Communications
Board
DSR message
Reception
Response
Send
3G3MV
D Step to Send and Receive Messages
·Sendingandreceivingmessagesasasinglestepincludesstep-typecommands,such
as Send, Recv, Send & Recv, and Wait commands.
·Thestepcanbefinishedorswitchedtoanotherstepaccordingtotheresultofthestep.
CPU Unit
PMCR
instruction
Communications
Board
Next process
according to
the result.
3G3MV
Step 0
To step n according to
the result.
H Configuration of Protocol Macro Function
·The protocol consists of one or more sequences.
A sequence is an independent set of actions to perform together with a general-pur-
pose peripheral device, such as an Inverter. The RUN command and the frequency
reference are given to the Inverter and the status of the Inverter is read in a single
sequence, for example.
·A sequence consists of one or more steps.
Communications Chapter 7
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