SIWAREX

Siemens SIWAREX is the weighing technology product line within the Siemens SIMATIC automation portfolio. SIWAREX weighing modules integrate directly into the SIMATIC S7-300, S7-400, and ET 200 I/O platforms, providing legal-for-trade and non-trade-legal weighing functionality within the same controller architecture used for the rest of the plant's process automation. Weighing and dosing are critical operations across a wide range of industrial processes. In mining, SIWAREX handles load monitoring on conveyor belts and ore weighing at transfer points. In food and pharmaceutical manufacturing, it manages dosing accuracy for batch formulation. In chemical processing, it supports filling and totalizing applications where weight measurement is part of the process control loop. A failed SIWAREX module disrupts the weighing loop and, depending on the application, can halt production. 

PLC Direct supplies Siemens SIWAREX hardware to customers for maintenance and component replacement in existing SIWAREX installations. Our collection covers weighing electronics modules for SIMATIC S7-300, ET 200M, and ET 200SP platforms. 

Where Siemens SIWAREX Hardware Is Used 

SIWAREX modules are deployed wherever weight or force measurement needs to be integrated directly into the SIMATIC control architecture, rather than handled by a standalone weighing indicator. 

Applications and facilities that rely on Siemens SIWAREX hardware include: 

• Mining operations using belt scales, hopper scales, and load cells for ore transfer and conveyor load monitoring 

• Chemical and pharmaceutical plants with precise dosing, filling, and batch weighing requirements 

• Food processing facilities with checkweighing, filling line control, and ingredient batch weighing 

• Cement and building materials production with raw material and finished product weighing 

• Plastics and rubber processing with continuous gravimetric dosing 

• Grain storage and agricultural commodity handling with totalizing scale applications 

Siemens SIWAREX Products 

The SIWAREX collection at PLC Direct covers weighing electronics modules for SIMATIC S7-300/ET 200M, SIMATIC ET 200SP, and ET 200S platforms, along with the SIWAREX U two-channel weighing electronics module. All product families and part number references below are confirmed on the live PLC Direct collection page. 

Product Families 

• SIWAREX U (Two-Channel Weighing Electronics): A two-channel weighing electronics module for connecting two independent scales to a single module, designed for SIMATIC S7-300 and ET 200M. Features RS232 interface for PC connection and TTY interface for remote display. Part number 7MH4601-1BA01 is confirmed in stock. 

• SIWAREX FTA (Single-Channel Legal-for-Trade Weighing Module): Single-channel weighing module for SIMATIC S7-300 and ET 200M, designed for automatic dosing, filling, checkweighing, and totalizing scales with analog load cells (full bridges, 1-4 mV/V). Includes 7 DI, 1 CI, 8 DQ, 1 AQ, RS485, RS232, and a load cell interface. Part number 7MH4900-2AA01 is confirmed in stock. This module carries announcement-of-phase-out lifecycle status. 

• TM SIWAREX WP321 ST (ET 200SP Weighing Module): Single-channel weighing module for the ET 200SP platform, for platform or hopper scales with analog load cells. Supports SIWAREX DB digital junction box for detailed load cell diagnostics. RS485 and load cell interface (1-4 mV/V), suitable for BU type A0. Part number 7MH4138-6AA00-0BA0 is confirmed to be in stock and an active product. 

• SIWAREX CS (ET 200S Weighing Electronics): Single-channel calibratable weighing electronics for the ET 200S platform, for use with ET 200S IM151-1 head station variants. RS232 and TTY interface. Part number 7MH4910-0AA01 is confirmed in the collection and has a product cancellation lifecycle status.  

Available at PLC Direct 

• SIWAREX U two-channel weighing electronics for SIMATIC S7-300 and ET 200M, RS232 and TTY interface (7MH4601-1BA01) 

• SIWAREX FTA single-channel legal-for-trade weighing module for SIMATIC S7-300 and ET 200M, 7 DI, 8 DQ, RS485/RS232 (7MH4900-2AA01) 

• TM SIWAREX WP321 ST single-channel ET 200SP weighing module, RS485, load cell interface (7MH4138-6AA00-0BA0) 

• SIWAREX CS single-channel ET 200S weighing electronics, RS232 and TTY (7MH4910-0AA01) 

What to Know Before You Buy Siemens SIWAREX 

Selecting the correct SIWAREX module requires matching the target SIMATIC platform, the number of scale channels required, and whether legal-for-trade (approved) weighing is a requirement of the application. 

Hardware condition options: We supply SIWAREX hardware as surplus sealed, refurbished, and used. Surplus sealed units are factory-sealed stock. Refurbished units have been tested and restored to operational condition. 

Platform compatibility: SIWAREX modules are platform-specific. SIWAREX U and FTA are designed for SIMATIC S7-300 and ET 200M. The WP321 ST is designed for ET 200SP. The SIWAREX CS is designed for ET 200S. These modules are not interchangeable across platforms and must match the SIMATIC platform installed in the application. 

Legal-for-trade requirements: SIWAREX FTA is designed for legal-for-trade applications (approved scales for filling, dosing, and totalizing). For applications where metrological approval is required by regulation, confirm that the SIWAREX variant selected meets the applicable national legal metrology requirements. 

Load cell interface: All SIWAREX modules in this collection interface with analog load cells using full-bridge strain gauge technology at 1-4 mV/V sensitivity. Confirm the load cell mV/V output before specifying the module. 

Lifecycle status: SIWAREX FTA carries phase-out status, and SIWAREX CS carries product cancellation status. For facilities maintaining installed SIWAREX FTA or CS equipment, PLC Direct provides an independent supply path for replacement modules outside standard OEM channels. 

Warranty: All Siemens SIWAREX hardware purchased from PLC Direct includes a standard 1-year warranty covering defects and functionality, applicable to surplus sealed, refurbished, and used products.