Allen-Bradley Compact 5000 User Manual

100 Rockwell Automation Publication 5069-UM003A-EN-P - May 2018
Appendix B Master Command List
Preset Multiple Registers (Function Code 16)
Query
The Function Code allows you to modify the contents of a Modbus 4x range
in the slave. This writes up to 125 registers at a time. Since the controller is
actively scanning, it can alter the content of any holding register at any time.
The following example is a request to write two registers starting at register
40002 in slave 11.
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.
TIP Functions 5, 6, 15, and 16 are the only messages that are recognized as valid
for broadcast.
TIP This is the structure of the message being sent out to the Modbus network.
The following byte values are in hexadecimal display.
Node
Address
Function
Code
Data Start
Address
High
Data Start
Address
Low
Number of
Points High
Number of
Points Low
Byte
Count
High
Data
Low
Data
High
Data
Low
Data
Error Check
Field
(2 bytes)
0B 10 00 01 00 02 04 00 0A 01 02 CRC
Node Address Function 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

Allen-Bradley Compact 5000 Specifications

General

Brand	Allen-Bradley
Model	Compact 5000
Category	Control Unit
Language	English