Rockwell-automation 1770-KF2 Data Highway or Highway Plus Interface Mo Manual de usuario descargar pdf (Pagina 123)

Message Packet Formats

Chapter 5

5-44

PLC-5 Commands

PLC-5 stations can execute the basic command set with the following

exceptions:

Set ENQs

Set NAKs

Set Timeouts

Set Variables

This section presents the message formats of the PLC-5 command and

reply messages. The table below lists the messages in the order they will

be discussed:

Message CMD FNC

Download

All Request

Download Completed

Modify PLC-2 Compatibility File

Read Bytes Physical

Read-Modify-Write

Set Processor Mode

yped Read

yped W

rite

Upload All Request

Upload Completed

rite Bytes Physical

ord Range Read

ord Range W

rite

Important: In the example formats that follow, CMD and FNC values

are expressed in hexadecimal notation. Other values are given in decimal

form.

Important: In addition to the message packet fields already described for

the basic command set, PLC-5 messages can also contain the following

fields:

1. PACKET OFFSET — Contains the word offset between the

DATA field of the current message packet and the DATA field of the

first packet in the transaction. This offset value appears only in

command messages for file transfers, where the complete transaction

might require more than one command or reply message packet.

Packet offset appears only in command messages for file transfers,

where the transaction might take more than one message packet to

complete. The value of PACKET OFFSET is zero for the first

packet in a transaction.

1 2 ... 118 119 120 121 122 123 124 125 126 127 128 ... 234 235

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Rockwell-automation 1770-KF2 Data Highway or Highway Plus Interface Mo Manual de usuario Pagina 123

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