Operation
Document No. D106-009
Page 57 of 76
Revision 1.15
5
Write Single Coil
6
Write Single Register
7
Read Exception Status
8
Diagnostic
11
Get Comm Event Counter
12
Get Comm Event Log
15
Write Multiple Coils
16
Write Multiple Registers
17
Report Server ID
20
Read File Record
21
Write File Record
22
Mask Write Register
23
Read/Write Multiple Registers
24
Read FIFO Queue
Table 4.6 - Common Modbus Functions
The following table shows common Status / Exception codes.
Code
Modbus Exception
0
Success
1
Illegal Function
2
Illegal Data Address
3
Illegal Data Value
4
Server Device Failure
5
Acknowledge
6
Server Device Busy
8
Memory Parity Error
10
Gateway Path Unavailable
11
Gateway Target Device Failed to
Respond
Table 4.7 - Common Exception Codes
4.3.1.
E
XAMPLE
In the following example, the unscheduled message instruction is used to read two Holding
Registers (0 and 1), from a remote Ethernet Modbus device located at IP address
192.168.1.219.