Sinclair SDV5-MOD, Руководство по эксплуатации, Страница: 6 / 24

1.5 Function Codes for Commands
NO. Function Name Function
0x02 Read Discrete Inputs Reads data.
0x03 Read Holding Register Reads data.
0x04 Read Input Register Reads data.
0x06 Write Single Holding Register Writes data.
0x10 Write Holding Registers Writes data.
1.6 Error Responses
A third-party device serves as the master Modbus device while SDV5-MOD serves as the
slave device.
The master device sends a request and waits for a response from the slave device. When no error
occurs, the slave device responds normally. If a data check error occurs, the slave device does
not respond. When data sent by the master device have an error other than the data check error,
the slave device responds with an error.
Meaning
The slave device receives a function
code that cannot be executed.
The received data address is not supported by the
slave device.
Code
0x01
0x02
0x03
0x06
Name
Invalid function code
Invalid data address
Invalid data
The slave device is busy
The slave device is busy processing a time-consuming
programcommand and the master device needs to
send the messagewhen the slave device is idle.
The value queried in the data area is not supported
by the slave device.
03