2 surecross® dx80 modbus register definitions, 1 modbus holding registers, 2 surecross – Banner SureCross DX80 Wireless Networks User Manual
Page 4: Dx80 modbus register definitions
2 SureCross
®
DX80 Modbus Register Definitions
Modbus distinguishes between inputs and outputs and between bit-addressable and word addressable data items.
. A less documented but commonly used method to separate the
data types is using a mapped address structure.
Reference
Description
0xxxx
Read/Write Discrete Output. Drives output data to a discrete output point.
1xxxx
Read Discrete Inputs. Controlled by the corresponding discrete input point.
3xxxx
Read Input Registers. Contains a 16-bit number received from an external source, like an analog
signal.
4xxxx
Read/Write Output or Holding Registers. Stores 16-bits of numerical data (binary or decimal), or
sends the data to an output point.
The xxxx represents the four-digit address location in user data memory. Because function codes generally denote the
leading character, the leading character is omitted from the address specifier for a given function. The leading character
also identifies the I/O data type. The SureCross DX80 Modbus registers are all holding registers 4xxxx using the mapped
address structure.
2.1 Modbus Holding Registers
There are sixteen Modbus holding registers for each SureCross
™
device. Calculate the holding register number for each
device using the equation: Register number = I/O# + (Node# × 16).
Because the Gateway is always first, at Node 0, the Gateway’s holding registers are registers 1 through 16. Registers for
Node 1 are 17 through 32, as shown in the Modbus Holding Register table below. Although only 10 Nodes are shown, the
table can continue for as many Nodes as are used in a given network.
Using the equation or the Modbus Holding Registers table, the register number for I/O point 15 for Node 7 is 127.
Modbus Holding Registers
I/O Pt.
Gateway
Node 1
Node 2
Node 3
Node 4
Node 5
Node 6
Node 7
Node 8
1
1
17
33
49
65
81
97
113
129
2
2
18
34
50
66
82
98
114
130
3
3
19
35
51
67
83
99
115
131
4
4
20
36
52
68
84
100
116
132
5
5
21
37
53
69
85
101
117
133
6
6
22
38
54
70
86
102
118
134
7
7
23
39
55
71
87
103
119
135
8
8
24
40
56
72
88
104
120
136
9
9
25
41
57
73
89
105
121
137
10
10
26
42
58
74
90
106
122
138
11
11
27
43
59
75
91
107
123
139
12
12
28
44
60
76
92
108
124
140
13
13
29
45
61
77
93
109
125
141
14
14
30
46
62
78
94
110
126
142
15
15
31
47
63
79
95
111
127
143
16
16
32
48
64
80
96
112
128
144
Host Controller Systems
4