Prosoft-technology MVI69E-MBTCP Manual do Utilizador descarregar pdf (Página 124)

Reference MVI69E-MBTCP ♦ CompactLogix Platform

User Manual Modbus TCP/IP Enhanced Communication Module

Page 124 of 150 ProSoft Technology, Inc.

May 20, 2015

In the above example, the client's Modbus command to transmit inside the

Modbus packet is as follows.

Server

Address

Function

Code

Address in

Device

Reg Count

Byte Count

Data

DEC

7100

85.37 22.86

HEX

1B BC

00 02

BD 71 42 AA E1 48 41 B6

In this example, the client's Modbus packet contains the data byte and data word

counts that have been doubled from the amount specified by Reg Count due to

the Float flag set to Y. Some servers look for the byte count in the data packet to

know the length of the data to read from the wire. Other servers know at which

byte the data begins and read from the wire the remaining bytes in the packet as

the data the client is sending.

Example #2: client is issuing Modbus command with FC 16 (with Float Flag: No) to transfer

Float data.

Float Flag: "N" tells the client to ignore the floating values and treat each

Float Start: Ignored.

DB Addr - same as when Float Flag: Y.

Reg Count - Tells the client how many data points to send to the server.

Swap Code - same as when Float Flag: Y.

Func Code - same as when Float Flag: Y.

Addr in Dev - same as when Float Flag: Y as long as the server's Float Flag = Y.

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Prosoft-technology MVI69E-MBTCP Manual do Utilizador Página 124