Siemens SIWAREX WP321 ST Weighing Electronics
Overview
The SIWAREX WP321 ST is a versatile and flexible weigh beam designed for seamless integration of static scales into the SIMATIC automation environment. It is part of the SIMATIC ET 200SP system series, leveraging modern automation features like integrated communication, operator control and monitoring, diagnostics, and project planning tools within TIA Portal, SIMATIC Step 7, WinCC flexible, and PCS7.
When used with the digital SIWAREX DB junction box, up to four connected load cells can be diagnosed separately. This allows the weigh beam module to detect individual load cell failures and provide relevant data, such as order number and location designation, directly to the CPU or HMI. This enhances operational reliability, reduces downtime, simplifies commissioning, and improves servicing. All messages and process values from individual load cell channels are accessible within the SIMATIC controller.
Benefits
- Uniform design technology and consistent communication within SIMATIC ET 200SP.
- Compact design with a module width of only 15 mm.
- Scales can be parameterized via the control panel, CPU, or PC.
- Flexible configuration options using SIMATIC TIA Portal, SIMATIC Step 7, and PCS 7.
- Measures weights and forces with a resolution of up to +/- 2 million parts.
- Supports measurement rates of 100/120/600 Hz.
- Internal scale monitoring for freely definable limit values.
- Easy commissioning with the SIWATOOL software.
- Automatic calibration is possible without the need for calibration weights.
- Modules can be replaced without recalibrating the scale.
- Direct use in ATEX Zone 2 is possible.
- Provides a wide range of status and diagnostic information.
- Includes a "Ready-for-use" sample program for quick integration.
Application
The SIWAREX WP321 ST is an optimal solution for applications requiring analog load cells for measuring tasks. It is suitable for:
- Non-automatic weighing instruments (NAWI), such as platform and hopper scales.
- Fill-level monitoring of silos and bins.
- Measuring of crane and cable loads.
- Force measurements.
- Monitoring of belt tensions.
- Setup of scales in hazardous areas.
Design
The SIWAREX WP321 ST is a technology module (TM) within the SIMATIC ET 200SP series, connected to the controller in a distributed manner via an ET 200SP interface module (PROFIBUS/PROFINET).
The following BaseUnits (Type AO) can be used for integration:
For opening a new potential group:
- BU15P-16+A10+2D (Article No.: 6ES7193-6BP20-0DA0)
- BU15P-16+A0+2D (Article No.: 6ES7193-6BP00-0DA0)
For continuing the potential group:
- BU15P-16+A10+2B (Article No.: 6ES7193-6BP20-0BA0)
- BU15P-16+A0+2B (Article No.: 6ES7193-6BP00-0BA0)
Load cells or force sensors are connected to the terminals of the BaseUnits, allowing for quick, easy, and wiring-free module replacement.
Function
The primary function of the weighing electronics is to determine current weight and force values based on signals from connected sensors. Seamless integration into the SIMATIC environment allows direct processing of these values in any available programming language of the CPU. Deviations from freely selectable and internally monitored values are reported directly to the controller. Status and diagnostic information can also be read out and evaluated in the CPU.
The SIWAREX WP321 ST is factory-calibrated, enabling automatic calibration without calibration weights and module replacement without recalibration.
An integral RS 485 interface allows connection to a PC for parameter setting using the "SIWATOOL" software, requiring a USB-RS 485 interface converter. Integration into the SIMATIC environment eliminates the need for complicated or expensive communication drivers for the scales. Weighing applications can be tailored and extended using TIA Portal, SIMATIC Manager, and WinCC flexible. The WP321 also supports scales in hazardous areas, potentially requiring the SIWAREX IS Ex interface depending on the zone and load cells used.
SIWAREX WP321 SIWATOOL
SIWATOOL is a service software tool for quick and efficient on-site calibration, parameter setting, and fault diagnostics. It allows for the creation and upload of complete backup files to new modules, enabling them to operate as before without recalibration. Configuration files created offline can also be uploaded, and the error buffer read out. No specialized SIMATIC knowledge is required. Connection is via the module's RS 485 port using a USB-RS 485 interface converter.
SIWAREX WP321 "Ready-for-use"
A free "Ready-for-use" sample project is available for easy introduction to module integration in TIA Portal and SIMATIC Manager. This project demonstrates hardware configuration, includes a communication function block between the CPU and SIWAREX, and provides a data block with all scale parameters. It also features touch panel configuration for complete commissioning from the panel, including an operator view for normal operation.
[Image Description: Screenshot showing the SIWAREX WP321 software interface with a weight reading of 78.0 kg.]
[Image Description: Screenshot of the SIWAREX WP321 HMI display showing a weight of 0.5 kg.]
Selection and Ordering Data
Weighing Electronics
| Description | Article No. |
|---|---|
| TM SIWAREX WP321 ST weighing electronics, single-channel, for platform scales or hopper scales with analog load cells (1...4 mV/V), 1 x LC, 1 x RS 485 | 7MH4138-6AA00-0BA0 |
Documentation & Software
| Description | Article No. |
|---|---|
| SIWAREX WP321 Equipment Manual (Available in multiple languages, free download at http://www.siemens.com/weighing/documentation) | N/A |
| SIWAREX WP321 "Ready-for-use" TIA Portal and SIMATIC Manager sample configuration (Free download at http://www.siemens.com/weighing/documentation) | N/A |
| SIWATOOL V4 & V7 Service and commissioning software for SIWAREX weighing modules | 7MH4900-1AK01 |
| SIWAREX PCS 7 AddOn Library for PCS7 V8.x and V9.0 (Supports PROFINET, APL faceplates and function blocks for SIWAREX U, FTA, FTC_B, WP321; Classic faceplate and function block for SIWAREX FTC_L) | 7MH4900-1AK61 |
Accessories (Mandatory Requirement)
| Description | Article No. |
|---|---|
| BaseUnit (Type AO - one BaseUnit required for each WP321) | |
| For opening a new potential group: BU15P-16+A0+2D | 6ES7193-6BP00-0DA0 |
| For opening a new potential group: BU15P-16+A10+2D | 6ES7193-6BP20-0DA0 |
| For continuing the potential group: BU15P-16+A0+2B | 6ES7193-6BP00-0BA0 |
| For continuing the potential group: BU15P-16+A10+2B | 6ES7193-6BP20-0BA0 |
| Shield connection for BaseUnit (5 units / for 5 scales) - For laying load cell cable | 6ES7193-6SC20-1AM0 |
Accessories (Optional)
| Description | Article No. |
|---|---|
| SIWAREX EB extension box - For extending sensor cables | 7MH4710-2AA |
| SIWAREX JB junction box, aluminum enclosure - For connecting up to 4 load cells in parallel, and for connecting multiple junction boxes | 7MH5001-0AA20 |
| SIWAREX JB junction box, stainless steel enclosure - For connecting up to 4 load cells in parallel | 7MH5001-0AA00 |
| SIWAREX JB junction box, stainless steel enclosure (ATEX) - For parallel connection of up to 4 load cells (for zone allocation, see manual or type-examination certificate) | 7MH5001-0AA01 |
| SIWAREX DB digital junction box - For enhanced diagnostic and monitoring options in conjunction with SIWAREX WP electronics | |
| Enclosure made of: Aluminum | 7MH5001-0AD20 |
| Enclosure made of: Stainless steel | 7MH5001-0AD01 |
| SIWAREX IS Ex interface - For intrinsically-safe connection of load cells. With ATEX approval (not UL/FM). Suitable for SIWAREX electronic weighing systems. Compatibility of load cells must be checked separately. | |
| Approved for use in the EU: Short-circuit current < 199 mA DC | 7MH4710-5BA |
| Approved for use in the EU: Short-circuit current < 137 mA DC | 7MH4710-5CA |
| Cable (optional): Cable Li2Y 1 x 2 x 0.75 ST + 2 x (2 x 0.34 ST) – CY | |
| For connecting SIWAREX electronic to junction box (JB), extension box (EB), digital junction box (DB), Ex interface (IS) or between two extension boxes. For permanent installation. Occasional bending is possible. External diameter: approx. 10.8 mm (0.43 inch). Permissible ambient temperature -40 ... +80 °C (-40 ... +176 °F). Sold by the meter. | |
| Sheath color: orange | 7MH4702-8AG |
| Sheath color (for hazardous atmospheres): blue | 7MH4702-8AF |
| RS 485/USB interface converter - Commercially available interface converter with FTDI chip, e.g. USB-Nano from CTI. (https://www.cti-shop.com/en/rs485-converter/usb-nano-485) | N/A |
| Remote display - The Siebert S102 and S302 remote digital displays can be directly connected to the SIWAREX WP321 via an RS 485 interface. (Siebert Industrieelektronik GmbH, PO Box 1180 D-65565 Eppelborn, Germany, Tel: +49 6806/980-9, Fax: +49 6806/980-999, http://www.siebert-group.com/en) | N/A |
Technical Specifications
SIWAREX WP321
| Parameter | Specification |
|---|---|
| Integration in automation systems | SIMATIC S7-300, S7-400, S7-1200 and S7-1500; Other manufacturers (with restrictions) |
| Communication interfaces | Via SIMATIC ET 200SP interface module (PROFIBUS or PROFINET); SIMATIC ET 200SP backplane bus; RS 485 (SIWATOOL, Siebert remote display) |
| Commissioning options | Using SIWATOOL V7; Using function block in SIMATIC CPU / Touch Panel |
| Measuring accuracy (According to DIN 1319-1 of full-scale value at 20 °C ± 10 K) | 0.05% |
| Internal resolution | ± 2 million parts |
| Measuring frequency | 100 / 120 / 600 Hz |
| Digital filter | Variable adjustable low-pass and average filter |
| Typical applications | Non-automatic weighing instruments; Force measurements; Fill-level monitoring; Belt tension monitors |
| Weighing functions | Weight values (Gross, Net, Tare); Limit values (2 x min/max, Empty); Zeroing, Tare, External tare specification, Calibration commands via controller or HMI |
| Load cells | Full-bridge strain gauges in 4-wire or 6-wire system |
| Load cell powering (Supply voltage, value applies at sensor, cable-related voltage drops of up to 5 V are controlled) | 4.85 V DC ±2% |
| Permissible load resistance (RLmin) | > 40 Ω |
| Permissible load resistance (RLmax) | < 4100 Ω |
| Permissible load resistance (RLmin with SIWAREX IS Ex interface) | > 50 Ω |
| Permissible load resistance (RLmax with SIWAREX IS Ex interface) | < 4100 Ω |
| Load cell characteristic | 1 ... 4 mV/V |
| Permissible range of measuring signal (at greatest set characteristic value) | -21.3 ... +21.3 mV |
| Max. distance of load cells | 1000 m (459.32 ft) |
| Connection to load cells in Ex zone 1 | Optionally via SIWAREX IS Ex interface (compatibility of the load cells must be checked) |
| Approvals/certificates | ATEX Zone 2; UL; FM; EAC; KCC; IECEx; RCM |
| Auxiliary power supply (Rated voltage) | 24 V DC |
| Auxiliary power supply (Max. power consumption) | Typ. 0.1 A @ 24 V DC (0.2 A max.) |
| Auxiliary power supply (Max. power consumption SIMATIC Bus) | 30 mA |
| IP degree of protection (to EN 60529; IEC 60529) | IP20 |
| Climatic requirements (T min (IND) ... Tmax (IND) - operating temperature) | Vertical installation in SIMATIC S7: -25 ... +50 °C (-13 ... 122 °F); Horizontal installation in SIMATIC S7: -25 ... +60 °C (-13 ... 140 °F) |
| EMC requirements | According to IEC 61000-6-2, IEC 61000-6-4, OIML R76-1 |
| Dimensions (width) | 15 mm (0.6 inch) |
Note: The S7 standard modules may not be operated at temperatures below 0 °C (32 °F). For operating conditions below 0 °C (32 °F), SIMATIC modules from the SIPLUS series must be used.
