Weighing module SIWAREX WP251

Weighing module SIWAREX WP251

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The very compact weighing module SIWAREX WP251 controls dosing and batching tasks completely independent while fulfilling the typical requirements of these processes, such as speed and accuracy.

As part of the SIMATIC S7-1200 basic controller family the module is integrated seamlessly into TIA-Portal. Optionally it also can be used without SIMATIC CPU in stand-alone mode.

Operation and commissioning of the scale are quick and easy: due to the free software example application “Ready-for-use SIWAREX WP251” the commissioning, calibration and operation of the scale can be done completely via the CPU or Touchpanel – thanks to the SIWAREX WP251 function block without any additional programming!

The integration into TIA-Portal allows an activation of user interfaces and an upload to all available SIMATIC operator panels. In combination with a SIMATIC S7-1200 basic controller, all customer and application specific requirements can be realized easily.

In the stand-alone mode all parameters and functions can be accessed and edited via the on board Modbus RTU or Modbus TCP/IP interface. In this case a PC or any Modbus-compatible device can be directly connected and used for operation.

Beside that the SIWAREX WP251 offers a trace function. All traced process values and status information of the scale can be illustrated and analyzed with SIWATOOL V7 and, if required, edited in spreadsheets.


Weighing applications Non-automatic weighing instrument (NAWI)
Automatic gravimetric filling instrument
Automatic catchweighing instrument
Integration in automation systems SIMATIC S7-1200
Other systems via Modbus RTU or
Modbus TCP/IP
Communication interfaces (on board) SIMATIC S7-1200 Bus
RS485 (Modbus RTU)
Ethernet (Modbus TCP/IP & SIWATOOL)
Internal resolution Up to +/- 4 million parts
Measuring rate 100/120Hz


  • Uniform structure and universal communication through the integration in S7-1200
  • Four digital in- and outputs, one analog output on board
  • Operation also possible without SIMATIC CPU
  • Flexible connections to different automation systems via on board Modbus RTU
    or  Modbus TCP/IP interfaces
  • High resolution of up to  +/- four million parts
  • Measuring rate of 100/120 Hz