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4.2 Modbus TCP/RTU Addressing
4.2.1 I/O Data Addressing
The GW-7433D provides a piece of the internal memory for saving I/O
data. The table 4-2 shows the detail information of the memory type, data type,
address, and so on. After using GW-7433D Utility to configure the mapping
information of the CANopen slaves, users can get the mapping table between
the Modbus address and CANopen data. The information of the Modbus
memory assignment and corresponding data type are shown below.
Memory
Type
Command
Start Addr
PLC
Start Addr
Max
channel
Support CANopen
Data Type
Support
Function
DI 0000h
00001h
3072 Boolean
2
DO
0000h
10001h
3072
Boolean
1, 5, 15
AI
0000h
30001h
640
Byte, Word, 4-byte
4
AO
0000h
40001h
640
Byte, Word, 4-byte
3, 6, 16
Table 4-2: I/O Data Addressing
4.2.2 Special Data Addressing
The GW-7433D supports special data such as the error status of the
CANopen slave, reset command, and so on. The table 4-3 shows the details of
these special data addresses.
Type
Address
Description
AI Max. AI a n
*1 *2
Read n
th
CANopen slave’s error status.
*4
AI
Max. AI a N + 1
*3
Read the GW-7433D’s error status.
*4
AI
Max. AI a N + 2
*3
Read the GW-7433D’s CAN status.
*5
GW-7433D MODBUS TCP/RTU to CANopen Gateway User Manual
26
(Version 2.1.0, Aug/2019)