Beckhoff Knowledge Base: Communication with Weather Station P02-RS485 / P03-RS485 from Elsner Elektronik GmbH


This Beckhoff Knowledge Base article describes application examples between TwinCAT and the Elsner Elektronik weather station P02-RS485 respectively P03-RS485 (
It only shows the basic functionalities necessary when integrating the weather station into own TwinCAT applications.

The weather station P02-RS485 uses the same communication protocol as the P03/1-RS485 or P03/3-RS485. Therefore, these weather stations are compatible to each other from the communication standpoint. The difference between the P03/1-RS485 and P03/3-RS485 is the number of available brightness sensors. The P03/3-RS485 uses 3 sensors (South, East and West). Instead, the P03/1-RS485 only contains 1 brightness sensor.

Elsner P02-RS485 / P03-RS485 Weather Station communication example - Overview 1:

The named weather stations sense the following weather conditions: Outdoor Temperature, Brightness, Wind Speed and Rainfall. In addition, a DCF-77 receiver is integrated in the housing. All data gets transferred via RS485 protocol. This data stream can be received and evaluated with a terminal device (i.e. a PLC). The actual data gets transferred every second from the weather station. If the weather station doesn't detect a valid DCF-77 signal, the data gets transferred approximately every 1.35 sec. In case the receiving control unit is speed capacity-wise a little undersized, Elsner Elektronik also offers a version which transfers the data only every 3 seconds.



Application examples Remarks
Application example 1:  Elsner P02-RS485 / P03-RS485 communicates with KL6041  
Application example 2:  Elsner P02-RS485 / P03-RS485 communicates with CXxxxxx-N031  
Protocol description Elsner P02-RS485 / P03-RS485