The HZS and HLS series concrete mixing station (building) made by the Fujian South Highway Machinery Co., Ltdadopt double-computer synchronized control system, of which the main hardware consists of two operation-control computers, a high performance programming logic controller (PLC),smart human-machine interface, high-speed & high-precision weighing unit and worldwide famous low-voltage electrical appliances (such as Schneider, ABB, Omron, MITSUBISHI).

1. Brief introduction
The HZS and HLS series concrete mixing station (building) made by the Fujian South Highway Machinery Co., Ltdadopt double-computer synchronized control system, of which the main hardware consists of two operation-control computers, a high performance programming logic controller (PLC),smart human-machine interface, high-speed & high-precision weighing unit and worldwide famous low-voltage electrical appliances (such as Schneider, ABB, Omron, MITSUBISHI). This system is integrated with this Company's self-designed control software and can achieve automatic control of concrete production process.

2. Characteristics
1.Advanced Double-Computer SynchronizedControl:
Investigations into the malfunction rate of concrete mixing station computer-control system reveals that the NO1. is computer problem. Once a malfunction occurs, the computers will halt operation and production will cease. The double-computer synchronizing control system has two computers which can control and manage the entire production process both independently or simultaneously. If one of the two computers malfunctions, the other one can automatically take control. Thus the system can maintain its control over the production process without the need for manual intervention.Thisimprovement drastically reduces computer-caused production suspension possibility to minimum.

2. High Performance Hardware Configuration Ensures Stable and Reliable Control
1) ADLINK industrial computers
2) MITSUBISHI PLChas excellent performance and a long life-span: it has super-high operating speed, the basic command is 0.08μs,MTBF(Mean Time Between Failure)is as high as 300,000 hours.
3) MITSUBISHI human-machine interface: English language version with wide visual angle, quick response rate and high performance.
4) MITSUBISHI AD Module high- speed conversion rate of 500μs, resolution is as high as 1/20000
5) Key low-voltage electrical appliances are allof world famous brands such as Schneider, ABB, Omron, etc.

3.Perfect Controlling Functions
1) A password is required for logging in to this software and calibrating the electronic scale. This effectively guarantees the security of important production data
2) The 3D interface uses animations to simulate the production status. It can display production datasuch as raw material values, weights and errors in real time.
3) It's allowed to arrange production tasks in advance and reset their sequence.
4) It may allocate output per batch automatically according to the overall output of production task and the mixing drum's capacity.
5) It can conduct self-diagnostic and provide users with hints.On-line help is also available
6) Functions available include falling error auto-calibration, trend estimation and negative-value auto-calibration as well as zero position auto-tracing and push-button tare-deduction.
7) Auto weight compensation or deduction will be conducted if the weight is lower or higher than required. The limit for measuring or unloading materials can be adjusted individually.
8) There is a window to alter the water rate contained in the aggregate so as to facilitate addition of sand and (or) reduction of water.
9) Water weighing can be paused at any moment and water formula adjustment is also available.
10) An invoice-loading service is available so that users may set up the invoice's layout design with office software and download it(can be used directly) into the control system
11)The control system is fitted with a data managementsub-system, which allows operator to carry out enquiry, view and print of relevant data.

4. User-Friendly and Easy to Maintain:
1) Auto, semi-auto and manual operation modes are available to make it easy to control the production process
2) Intelligent parameter setting makes it possible to set up all of the operation experience parameters with a push of one button
3) Users may customize the production procedures, mixing time and unloading order according to their production needsand usage habits
4) The mixing drum's discharge gate may be controlled automatically by the system, switching its position between closed, half-open and fully-open. Manual operation for gate positioning is easy, flexible and convenient
5) The equipment's production status can be comprehensively detected in real time and safety interlock controlcan be conducted. If something abnormal occurs, the system can point out the location of malfunction and prompt the operators to perform checks and repairs, thusthe location of the malfunction can beidentified and it can be eliminated.
6) Traditionally it applies industrial computer to carry out process control, however due to software and hardware problems, once fault occurs it's hard for average computer maintenance technician to deal with, which causes a lot of head ache to customers. NFLG has made great progress in development ofelectronics, so that it's feasible to replace industrial computer with general one. This adaptation makes convenient for customers to maintain and update control system, eliminating lots of potential trouble.