Siemens SIWAREX WP251 Weighing Electronics


  • Uniform design technology and consistent communication in SIMATIC S7-1200
  • Uniform configuration with TIA Portal
  • Legal-for-trade according to OIML R76, R51, R61 and R107
  • Internal alibi memory for up to 550 000 entries
  • Operation without SIMATIC CPU possible
  • Ethernet port ex works (Modbus TCP/IP / SIWATOOL)
  • RS 485 interface ex works (Modbus RTU / remote display)
  • Four digital inputs and outputs, one analog output ex works
  • Measurement of weight and force with a high resolution of up to ± 4 million parts and an accuracy of 0.05%
  • Simple adjustment of scale using the SIWATOOL V7 program via the Ethernet interface
  • Recovery point for simple restoration of all parameters
  • Automatic calibration is possible without the need for calibration weights
  • Supports replacement of module without recalibration of scales
  • Direct use in hazardous area zone 2

Siemens SIWAREX WP251 Weighing Electronics is an adaptable weighing module designed for dosing and filling operations. This compact module can be easily integrated into the SIMATIC S7-1200 automation system or operate independently in stand-alone mode without the need for a SIMATIC CPU.


Weighing modes – Non automatic weighing instrument (NAWI) (filling + removal) (legal-for-trade in accordance with OIML R76)
– Catchweighing instrument (CWI) (filling + removal) (legal-for-trade in accordance with OIML R51)
– Gravimetric filling instrument (GFI) (legal-for-trade in accordance with OIML R61)
– Discontinuous totalizing automatic weighing instrument (DTI) – (legal-for-trade in accordance with OIML R107)
Ports 1 × SIMATIC S7‑1200 system bus
1 × Ethernet (SIWATOOL and Modbus TCP/IP)
1 x RS 485 (Modbus RTU or remote display)
1 x analog output (0/4 – 20 mA)
4 × digital inputs (24 V DC, floating)
4 × digital outputs (24 V DC, floating, short-circuit proof)
Functions 3 limits
Tare specification
Zero adjustment
Automatic correction of the shut-off points
Internal protocol memory for 550 000 entries
Trace function for signal analysis
Internal restore point
Stand-alone mode or SIMATIC S7-1200 integrated
Parameter assignment – Full access using function block in SIMATIC S7-1200
– Full access using Modbus TCP/IP
– Full access using Modbus RTU


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