elsner elektronik 30146, Installation And Adjustment

5

Transfer protocol

Weather Stations P03/3-Modbus(-GPS)

 • Version: 07.06.2022 • Errors excepted. Subject to technical changes.

Setting of the slave’s address: 

The slave address is set with the help of the 8-bit DIP switch “Address”. If all switches
are in the OFF position, Address 1 is active. Address 0 is reserved for broadcast mes-
sages; addresses greater than 247 are not valid. 

The coding of the address is binary. For the address 47, you must e.g. set the switches
3, 5, 6, 7 and 8 to ON. 

Interface parameters:

The interface parameters are set with the help of the second 8-bit DIP switch. If the first
4 switches are in the OFF position, the transfer rate amounts to 19,200 bauds. If one of
these switches is set to ON, the corresponding baud rate is applicable.

Parity:

 If the two switches “ODD” and “NONE” are set to OFF, the parity is EVEN. Only

“ODD” or “NONE” can switch the corresponding parity check. 

Switch “Mobu EE”:

 no function.

Switch “Term.”:

 bus termination 124 ohms

3.3. Notes on commissioning

The correct wind value may only be supplied approximately 60 seconds after the sup-
ply voltage has been connected.

4.

Transfer protocol

4.1. P03-Modbus request string from the master

Example query string for reading all data:
0x01 0x04 0x00 0x00 0x00 0x11 0x30 0x06

Byte 
No.

Variable

Meaning

0

Slave address

xx

1

Command

04H

Read Input Registers

2

Start address High Byte

xx

Register start address

3

Start address Low Byte

xx

4

Number of words High Byte

xx

Number of registers to be read

5

Number of words Low Byte

xx

6

CRC Low Byte

xx

7

CRC High Byte

xx