PWC is abbreviated from Programmable Weighing Controller. Launched in 2018, PWC is a new generation controller that combines Programmable Logic Control with weighing functions. It has the proficiency to adopt multi component design, thus PWC has the flexibility to match modules of various functions. The PWC can be structured as a centralized control system and can also be structured as a distributed control system, meeting requirements of various site requirements. Users have the flexibility to configure functions by themselves to build a platform that is convenient for secondary requirement, professionally and cost effectively. The development of PWC is indeed groundbreaking where weighing technology is combined with automatic control technology.

PWC uses the matured and reliable CAN field bus technology to connect its controller and module. While the field wiring is effectively reduced compared to general setting, the number of functional modules that can be connected in the PWC is up to 32 modules. This is by far the most cost effective control system in the market.

System Introduction
PWC is able to take on multi component design allowing users to choose different functional modules for flexible matching in accordance to the system requirements. While there is flexible matching to the system, it also provides the control system easy expansion for future functional change requirements. It only requires corresponding functional modules for functional expansion change requirement thus effectively utilizing the original investment and reducing overall cost.

CAN is an industrial data bus that was developed rapidly in recent years. It mainly solves the digital communication between field devices such as intelligent instruments, controller and actuators. It also transmit information between these field devices and advanced control systems. The advantage of CAN is it is simple, reliable, economical and practical. The PWC uses the CAN bus for connection between the functional modules of the PWC. CAN-open is used for high level protocol which allow access to a maximum of 32 functional modules. The PWC function module has a baud rate adaptive function which eliminates the requirement to manually set the communication baud rate for CAN bus. The PDO mapping communication mode is adopted between control module MC700 and each functional module, and the data of instruments are directly mapped to the D component area inside the PLC, which is convenient for reading and writing.

PWC possess the same logic control function as PLC. The programming language can use Ladder Diagram (LAD), Statement List (STL), Flow Chart (SFC) and others as well. The programming language uses the LT logic language independently designed by Changlu. The language instruction fully absorbs the advantages of Siemens, Mitsubishi and other instructions. At the same time, combined with the results accumulated by Longtec in the weighing field for many years, the LT logic language has compiled a compacted command of coding and execution. The LT logic language has the advantage of high speed and convenient writing. Taking into consideration of widespread usage of Mitsubishi PLC and in order to reduce the learning difficulty of users and protect the smooth transition of original equipment and programs, PWC uses not only Longtec PLC programming software but also is compatible with Mitsubishi’s PLC programming software GXDeveloper.

TR700 Weighing Module in PWC
The TR700 series weighing module in PWC adopts adaptive model predictive algorithm which makes the functions of control model self-learning and control parameter self-adjustment. At the calibration stage of the weighing system, the instrument can automatically learn the characteristics of the on-going used system, and is capable to implement the control in advance for the subsequent control, so that the control can be accurate, the response is fast and the adjustment load is small, etc.

 

MC700 control module in PWC
The MR700 uses standard Modbus protocol and performs using HPS software that is independently developed by Changlu. The MR700 can also be connected by touch screen to a large range of popular PLC brands and PCs to complete recipe downloads, report generation, data screen monitoring, etc. The MC700 has available RS232C, RS-485 and Industrial Ethernet Modbus-TCP interface. Through the Modbus protocol, user can read and and write all the bit components and D components of the PLC of the MC700, and at the same time, user can also read and write any weight control bit table in the CAN network e.g. TR700 etc. which then automatically converts the protocol internally.

 

TR700 series weight change transmitter controller
The TR700 series weight change transmitter controller not only has a perfect communication interface such as RS-232C, RS-485, CAN-bus, Profi-DP, CC-Link but also has buttons, 6-digit LED display, additional external display screen “Connect” for extended display and display communications methods which are very flexible.

The PWC is produced by incorporating reliable industrial grade devices, it has low heat generation and does not require external fans to dissipate heat, it also has good sealing and is dust proof. It can be customized to meet different environmental and temperature requirements.  All the functional modules of PWC are installed on DIC35mm rails which are specially designed to meet the characteristics of industrial weighing automatic control, using SMT production technology and industrial grade components. They are small in size, require less wiring and  has strong anti interference that are in line with online process weighing requirement.

PWC installation for Application field
The PWC can be installed centrally or various site distribution, which makes it convenient for secondary development by users. It is the preferred product for industrial weighing automation.

PWC installation as a platform for weight data acquisition system
The MC700 carries out CAN data communication with each instrument module, reading and registering various weight data thus the host computer only needs to communicate with MC700.

The serial port or Ethernet connection has high communication efficiency making it easy to write software and is capable to read the weight data of all the instruments simultaneously thus occupying less serial port resources.

It can complete weight and related data collection in manual weighing, semi-automatic weighing, logistic and storage weighing, and various other industry fields where PLC and PC is required to complete weight and batching control.

PWC installation for rapid packaging, filling and weighing system
In rapid packaging, filling and weighing system, quantitative control is completed by TR700. The execution of MC700 program and the reading of the weight data of each instrument is very fast, allowing to meet the requirement of high speed packaging and filling/dosing weighing. Using the various IO interfaces, the PLC program can be written to complete a single scale or a control of multiple scale system.

PWC installation in various weighing and batching systems
MC700 possess the same logic control function as PLC. It automatically reads the weight and other date of each weight control instrument into the PLC through the CAN bus in the form of PDO. The user only needs to write the corresponding PLC program according to the control process in order to complete the batching control. The new TR700C is directly equipped with batching function. When forming a control system with TR700C, the user only requires to write a simple PLC program to complete the logic.