ProSoft Technology CompactLogix MVI69E-MBS, Руководство пользователя

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MVI69E-MBS ♦ CompactLogix™ Platform Reference
Modbus Serial Enhanced Communication Module User Manual
ProSoft Technology, Inc. Page 125 of 159
8.2.12 Preset Multiple Registers (Function Code 16)
Query
This Function Code allows you to modify the contents of a Modbus 4x range in the slave.
This writes up to 125 registers at time. Since the controller is actively scanning, it also
can alter the content of any holding register at any time.
Note: Function codes 5, 6, 15, and 16 are the only messages that are recognized as valid for broadcast.
The example below is a request to write 2 registers starting at register 40002 in slave 11.
Note: This is the structure of the message being sent out to the Modbus network. The byte values below are
in hexadecimal display.
Node
Address
Func
Code Data Start
Address
High Data Start
Address
Low Number
of Points
High Number
of Points
Low Byte
Count
Data
High
Data
Low Data
High Data
Low Error
Check
Field (2
bytes)
0B
10 00 01 00 02 04 00 0A 01 02 CRC
Response
The normal response to a function 16 query is to echo the address, function code,
starting address and number of registers to be loaded.
Node
Address
Func
Code Data Start
Address
High Data Start
Address
Low Number
of Points
High Number
of Points
Low Error Check Field (2 bytes)
0B
10 00 01 00 02 CRC