User manual

IEC61131 User and Reference Manual
April 22, 2008
316
Function
Code
Purpose
Description
Maximum
Registers
16
Write Multiple Holding
Registers
Write analog output registers.
60
DF1 Function Codes
Function
Code
Description
Purpose
Maximum
Registers
00
Protected Write
Writes words of data to limited
areas of the database.
121
01
Unprotected Read
Reads words of data from any
area of the database.
122
02
Protected Bit Write
Sets or resets individual bits
within limited areas of the
database.
1
05
Unprotected Bit Write
Sets or resets individual bits in
any area of the database.
1
08
Unprotected Write
Writes words of data to any area
of the database.
121
Enron Modbus Function Codes
Function
Description
Purpose
Maximum
Registers
128
Read Enron Boolean
Read Enron Boolean registers
2000
129
Write Enron Boolean
Write Enron Boolean register
1
130
Write Enron Multiple
Boolean
Write Enron Boolean registers
880
131
Read Enron Short Integer
Read Enron short integer
register
125
132
Write Enron Short Integer
Write Enron short integer
register
1
133
Write Enron Multiple Short
Integer
Write Enron short integer
registers
60
134
Read Enron Long Integer
Read Enron long integer
register
62
135
Write Enron Long Integer
Write Enron long integer
register
1
136
Write Enron Multiple Long
Integer
Write Enron long integer
registers
30
137
Read Enron Floating Point
Read Enron floating-point
register
62
138
Write Enron Floating Point
Write Enron floating-point
register
1
139
Write Enron Multiple
Floating Point
Write Enron floating-point
registers
30
Notes
Note that only one master function block may be active on each serial communication port
at any one time.