I-7530A-MR Modbus RTU to CAN
Converter User’s Manual (Version 1.08, 07/2019) ------------- 103
7.3.3
Common Configuration
CAN Error Response Message:
CAN Error Response:
This function is used to transmit an error message via CAN bus when
the Modbus communication error or command timeout is detected.
When this function is checked, the
“CAN Specification” field and “Error
Response CAN ID
” field will be enabled.
CAN Specification:
This field indicates this CAN message uses CAN 2.0A or CAN 2.0B. If
the CAN 2.0A is selected, the maximum value of CAN ID is 0x7FF.
Relatively, if the CAN 2.0B is selected, the maximum value of CAN ID
is 0x1FFFFFFF.
Error Response CAN ID:
This field indicates the error message with this CAN ID will be
transmitted when I-7530A-MR detects an error.
The CAN response message format is as following:
Error Response CAN Message Format:
CAN ID
Data
Length
Data Byte0 Data Byte1~
Data Byte3
Data Byte4~
Data Byte6
Data
Byte7
Error Response
CAN ID
8
Identifier
Code
Reserved
Modbus
Exception
Reserved
The
“Identifier code” in Data Byte0 is divided into four types:
Identifier Code
Description
0x00
Reserved
0x01
It indicates the current Modbus command is
transmitted completely and the I-7530A-MR
receives the wrong Node id command
0x02
It indicates the current Modbus command is
transmitted completely, but the I-7530A-MR
does not receives any response command