Adamczewski GmbH
Manual AD-MM 500 FE
8 Modbus
The AD-MM 500 FE basically works as a Modbus master on its RS-485 interface. The operating
mode as Modbus slave is not intended for the AD-MM 500 FE .
RS-485 Interface parameters
The RS-485 interface works with the following settings as standard. There is currently no provi-
sion for changing these parameters and it is not necessary when using ADAMCZEWSKI elektro-
nische Messtechnik GmbH devices.
Name
Value
Baudrate
19200
Data bits
8
Parity
gerade
Stopp bits
1
Data types
The following data types are used.
Type
Size
Words
bool
1 Byte
1
u16
2 Byte
1
u32
4 Byte
2
single(IEEE 754)
4 Byte
2
According to the Modbus specification, words with two bytes are transmitted as the smallest unit
in the ’Big-Endian’ format. All information is therefore a multiple of a word. The checksum is an
exception. It is sent in the ’little endian’ format (least significant byte first).
Modbus functions used
The AD-MM 500 FE only uses the two functions for communication with the slaves
3 (0x03)
Read Holding Registers.
16 (0x10)
Write Multiple Registers.
The following abbreviations are used to explain the telegrams:
SA
Slaveaddress
FC
Functioncode
RH
Register Highbyte
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1.0 2021-05-19