Siemens TM SIWAREX WP521 ST & WP522 ST Weighing Electronics


  • Uniform design technology and consistent communication in SIMATIC S7-1500
  • Uniform configuration with TIA Portal
  • Single (WP521 ST) and dual-channel (WP522 ST) variants are available
  • Operation possible without or with failed SIMATIC CPU
  • Optional direct connection of an operator panel via Ethernet port (Modbus TCP/IP)
  • Optional direct connection of a remote display via RS 485 interface
  • Modbus TCP/IP interface
  • Modbus RTU interface
  • Three digital inputs and four digital outputs
  • Measurement of weight or force with a high resolution of up to ± 4 million parts and a measurement rate of 100/120 Hz
  • Simple commissioning by means of HMI/CPU or PC software SIWATOOL V7 via the Ethernet interface
  • Recovery point for simple restoration of all parameters
  • Automatic calibration is possible without the need for calibration weights
  • Module can be replaced without renewed adjustment of scale
  • Automatic impedance monitoring of the connected load cells
  • Direct use in hazardous area zone 2
  • Up to eight 350 ohm load cells can be connected per channel
  • High EMC resistance

Siemens TM SIWAREX WP521 ST & WP522 ST Weighing Electronics (ST = Standard) are adaptable weighing modules designed for the SIMATIC S7-1500 Advanced Controller family. These electronic weighing systems enable the seamless integration of basic weighing tasks, such as platform or hopper scales, into the S7-1500 automation ecosystem.


Weighing modes Non-automatic scales, e.g. platform and hopper scales
Ports v1 × SIMATIC S7‑1500 system bus
1 × Ethernet (SIWATOOL, Modbus TCP/IP)
1 × RS 485 per channel (Modbus RTU or remote display)
3 × digital inputs per channel (24 V DC)
4 × digital outputs (24 V DC short-circuit proof) per channel
Functions 3 limits
Tare specification
Zero adjustment
Trace function for signal analysis
Internal restore point
SIMATIC S7-1500 integrated and/or stand-alone operation
Parameter assignment Using function block in SIMATIC S7-1500 and HMI
Using Modbus TCP/IP
Using Modbus RTU
Weight values Gross
Limit values 2 × min/max
1 ×Empty


Siemens TM SIWAREX WP521 ST WP522 ST Weighing Electronics_DpstarGroup