20 - 70
71130/11E/0318
6.2 Warranty
Damage caused by improper handling or external influences, e.g. strike by lightning, are not
covered by the warranty provisions. The warranty is void if the device is opened.
Important:
The WEATHER STATION must be returned in the original
packaging.
7 Functional description
The functions of the WEATHER STATION are described below.
7.1 Command interpreter MODBUS RTU
If the command interpreter MODBUS RTU has been selected, the transmitted bytes will be
interpreted according to the MODBUS specification (http://www.modbus.org/). The Weather station
acts as a MODBUS slave here.
Data is transmitted in packets, so-called frames, max. 256 bytes in length.
Every packet includes a 16-bit CRC check sum (initial value: 0xffff).
Slave address
Function code
Data
CRC
1 byte
1 byte
0...252 byte(s)
2 bytes
CRC low-byte
CRC high-byte
Table 2 : MODBUS frame
The following MODBUS functions are supported:
-
0x04 (read input register).
-
0x03 (read holding registers).
-
0x06 (write single register).
-
0x10 (write multiple registers).
The sensor supports write access for the slave address 0 ("Broadcast").
All MODBUS requests received are checked for validity before execution. With any error the
weather station responds with one of the following exceptions (
MODBUS Exception Responses).
Code
Name
Meaning
0x01
ILLEGAL FUNCTION
The function code in the request is not permissible for the
register address.
0x02
ILLEGAL DATA ADDRESS
The register address in the request is invalid.
0x03
ILLEGAL DATA VALUE
The data given in the request are not allowed, or the
parameter is write-protected
.
Table 3: MODBUS exceptions
