DDC feeder
Publish: 2021-05-07 11:29:03
1.
There are two meanings
Dewey Decimal Classification (DDC) is widely used by libraries all over the world In direct digital control system (DDC), the computer collects real-time data through analog input channel (AI) and switching input channel (DI), then calculates according to certain rules, finally sends out control signals, and directly controls the proction process through analog output channel (AO) and switching output channel (do)2. DDC (direct digital control) is a direct digital control, which is usually called DDC controller. DDC system usually consists of central control equipment (centralized control computer, color monitor, keyboard, printer, uninterruptible power supply, communication interface, etc.), field DDC controller, communication network, corresponding sensors, actuators, regulating valves, etc.
it replaces traditional control components, such as temperature switch, receiving controller or other electronic mechanical components, The performance is better than single chip microcomputer, PLC and so on. It is a general mode of building environment control. DDC system uses micro signal processor to perform various logic control functions. It mainly uses electronic drive, but it can also connect pneumatic mechanism with sensors. The biggest characteristic of DDC system is that digital control function is used in every link from parameter acquisition, transmission to control. At the same time, a digital controller can realize the functions of multiple conventional instrument controllers, and can have multiple control loops of different objects
working principle
all the control logic is completed by the micro signal processor and based on each controller. These controllers receive input signals from sensors, common contacts or other instruments, process these signals according to software programs, and then output the signals to external devices. These signals can be used to start or shut down the machine, open or close the valve or damper, or perform complex actions according to the program. These controllers can operate the central machine system or terminal system by hand
DDC controller is the core of the whole control system and the key component to realize the control function of the system. Its working process is that the controller collects real-time data through analog input channel (AI) and digital input channel (DI), transforms analog signal into digital signal acceptable to computer (A / D conversion), then carries out operation according to certain control law, finally sends out control signal, and transforms digital signal into analog signal
it replaces traditional control components, such as temperature switch, receiving controller or other electronic mechanical components, The performance is better than single chip microcomputer, PLC and so on. It is a general mode of building environment control. DDC system uses micro signal processor to perform various logic control functions. It mainly uses electronic drive, but it can also connect pneumatic mechanism with sensors. The biggest characteristic of DDC system is that digital control function is used in every link from parameter acquisition, transmission to control. At the same time, a digital controller can realize the functions of multiple conventional instrument controllers, and can have multiple control loops of different objects
working principle
all the control logic is completed by the micro signal processor and based on each controller. These controllers receive input signals from sensors, common contacts or other instruments, process these signals according to software programs, and then output the signals to external devices. These signals can be used to start or shut down the machine, open or close the valve or damper, or perform complex actions according to the program. These controllers can operate the central machine system or terminal system by hand
DDC controller is the core of the whole control system and the key component to realize the control function of the system. Its working process is that the controller collects real-time data through analog input channel (AI) and digital input channel (DI), transforms analog signal into digital signal acceptable to computer (A / D conversion), then carries out operation according to certain control law, finally sends out control signal, and transforms digital signal into analog signal
3. Direct digital controller is the local control equipment, which is generally used in intelligent buildings. It is the status information of the object controlled by the field control equipment and mobile phone, and then it is sent to the upper computer for comprehensive management
4. Unknown_Error
5. DDC is actually a trade name. It is the delivery fee that the receiving party should pay when receiving the goods, not the name of the logistics company. If you want to find the whereabouts of the goods, you can inquire according to the order number and call your local Shentong express company!
6. Intelligent building BAS system detection method
intelligent building uses advanced computer technology, control technology and communication technology to provide users and managers with a complete control function, convenient data processing, centralized display and operation, safe and reliable building automation system (BA system for short). BA system adopts the distributed control technology to monitor the building equipment comprehensively and in real time, which improves the operation quality of the building equipment, reces the workload of management, and reces the energy consumption of buildings. It plays an important role in the building intelligent system. However, for a long time, the quality of BA system engineering in China has been poor, and there are not many Ba systems in normal operation. The main reason is that the detection and acceptance of BA system engineering has not been established on a scientific basis
in the past three years, in order to cooperate with the government and owners in the completion and acceptance of the intelligent system project, we have successively tested the BA system of Jiushi Fuxing building, post and Telecommunications Training Building, Shanghai Tongmao building, Volkswagen building, Shanghai Pudong Development Bank Bund 12 building, Zhaofeng Global building, Zhaofeng World Trade Building and Securities Building in Shanghai. The power supply system, cold and heat source system, air conditioning system, lighting system, water supply and drainage system, garage management system, etc. under the monitoring of BA system are tested, and the real-time performance, reliability, safety, easy operation, easy maintenance and control accuracy of BA system are evaluated as important indicators of the system. This work has promoted the BA system engineering contractor to make efforts to rectify and improve the quality of the project, which has not only achieved good social benefits, but also included the results of the work in the draft of Shanghai intelligent building series standards
1. Discussion on the detection method of BA system
the detection work of BA system should first fully understand the function and performance index of the whole system according to the engineering design documents and contract technical documents. The main documents to be provided by the owner and contractor of the tested system include system type selection demonstration, system scale and capacity, control process description, system function description and performance index, BA system structure diagram, control schematic diagram of each subsystem, BA system equipment layout and wiring diagram, power distribution box electrical schematic diagram related to BA system monitoring, field equipment installation diagram, and so on DDC station and central management workstation operator station monitoring process flow chart, central monitoring room equipment layout, BA system supply contract and engineering contract, BA system construction quality inspection record, relevant engineering design change order, BA system operation record. On this basis, according to the acceptance standard of BA system, a set of reasonable BA system detection scheme is worked out
detection is generally divided into three levels: central monitoring station, subsystem (DDC station) and field equipment (sensors, transmitters, actuators, etc.) for function detection
1.1 detection of the central monitoring station
the central monitoring station is a central processing device that collects, refreshes, controls and alarms the DDC station data of each subsystem in the building. The detection items are as follows:
observe the changes of the site status on the central monitoring station, whether the status data on the screen of the central monitoring station is constantly refreshed and its response time
through the central monitoring station to control the analog output or digital output of the subordinate system, observe whether the action of the on-site actuator or object is correct and effective, and the time when the action response returns to the central monitoring station
when a fault is created on the input side of the DDC station, observe whether there is alarm fault data logging in on the screen of the central monitoring station, and send out an audible prompt and its response time
if the central monitoring station loses power artificially, after the power transmission is restored, can the central monitoring station automatically restore all monitoring and management functions
check whether the central monitoring station gives operation authority to the operators to ensure the security of BA system. It should be confirmed by the refusal of illegal operation and ultra vires operation
whether the man-machine interface is Chinese or not, the central monitoring station screen can query, control the equipment status, observe whether the equipment operation process is intuitive and convenient, so as to verify the friendly interface
check whether the central monitoring station has the function of status self diagnosis of equipment group
check whether the display and printer of the central monitoring station can provide information about the operation time, area, number and status of all or important equipment in the form of report graph and trend graph
check whether the system provides software tools for system design, application and graphics creation
check whether the parameters of the control object set by the central monitoring station are consistent with the design accuracy
check whether the operation status data of each equipment displayed by the central monitoring station is complete and accurate
1.2 detection of subsystem
the subsystem (DDC station) is a computer monitoring system that can run independently. It continuously collects, calculates, controls and alarms the process signals of various sensors and transmitters on site, and transmits them to the database of the central monitoring station (upper computer) through the communication network for real-time display, control and alarm of the central monitoring station Alarm, printing, etc
the items of the detection subsystem are as follows:
the central monitoring station is shut down artificially to observe whether each subsystem (DDC station) can work normally
after the artificial manufacturing subsystem (DDC station) loses power, whether the subsystem can automatically restore the operation state set before power loss after power transmission is restored
the communication network between the man-made subsystem (DDC station) and the central monitoring station is interrupted, whether the field equipment maintains normal automatic operation state, and whether the central monitoring station has the fault alarm signal of DDC station logging in
to detect whether the clock of the subsystem (DDC station) is synchronized with that of the central monitoring station, so as to realize the monitoring of various subsystems (DDC station) by the central monitoring station
1.3 detection of field equipment
according to the system design monitoring requirements, the electrical signal is divided into analog quantity and switching quantity. Sensors and transmitters are devices that convert various physical quantities (temperature, humidity, pressure difference, flow, electric valve opening, liquid level, voltage and current, power, power factor, operation state, etc.) into corresponding electrical signals. The actuator is a device that works according to the control signal output by DDC. The inspection items of field equipment are as follows:
check whether the installation of sensors, transmitters, actuators and DDC boxes is standard, reasonable and easy to maintain
check whether the data and status displayed by the central monitoring station are consistent with the on-site reading and status
check whether the action or sequence of the actuator is consistent with the designed process
whether to generate alarm signal when the parameter exceeds the allowable range
whether the action of the actuator under the control of the central monitoring station is normal
1.4 function detection
BA system usually monitors building equipment by function and area. Therefore, the detection function is also performed by region. Take air conditioning and public lighting areas for example. The air conditioning area is the place where people work and rest. Under the control of BA system, the air conditioning system should provide comfortable indoor temperature and good air quality. The items for testing air conditioning and public lighting areas are as follows:
testing whether the central monitoring station can control the air conditioning system according to the schele
check whether the temperature and humidity in the air conditioning area are consistent with the data displayed in the central monitoring station
to detect whether the indoor carbon dioxide content meets the health standard
check whether the lights in public lighting area can be switched on and off and night lighting can be set according to the time program, so as to achieve the purpose of energy saving
through the detection of the above three levels and functions, we can make a comprehensive evaluation on the real-time performance, reliability, safety, easy operation, easy maintenance, installation quality and control accuracy of BA system, and put forward rectification suggestions for the existing problems. Through rectification, the tested BA system can run normally
many problems are always found in BA system engineering inspection. After a certain period of rectification, most Ba systems basically meet the functions and technical indicators listed in engineering design documents and contract technology, and the system runs well, which can achieve certain energy-saving effect. The qualified BA system is effective in monitoring the construction equipment, and the real-time response of detection, control and alarm is fast; The operation interface has the advantages of high Sinicization rate, convenient operation and maintenance, and comprehensive equipment management; The system has strict control over operators' authority and clear hierarchy; The system works reliably; The control precision of air conditioning area can meet the air conditioning design requirements
first, a small number of architectural, HVAC and electrical designers did not cooperate well in the preliminary design, so that the space of the air-conditioning box room was too small and the equipment maintenance channel was difficult to walk. Or the position of fresh air outlet is unreasonable, and the quality of fresh air is not ideal
secondly, some Ba designers are not familiar with the construction equipment and the integrity of the system, resulting in the error of sensor location equipment, and even the lack of sensors and software tools
thirdly, a few Ba designers do not have a comprehensive understanding of the operating conditions and process of the air conditioning system. As a result, the operation control mode of BA system for the air conditioning system is unreasonable, and the effective energy-saving goal is not achieved
fourthly, some construction workers did not operate according to the specifications ring the equipment installation, such as wrong wiring, wrong sensor installation position, weak connection between actuator and equipment, disordered wiring in DDC box, no protective rubber washer at the inlet and outlet of the box, and disorderly pulling of metal hose, which brought hidden dangers to the normal operation of the system
fifthly, a few property management companies failed to carry out necessary maintenance in the operation of BA system, resulting in the continuous failure of the original normal system
3. Conclusion
the purpose of BA system engineering in intelligent building is to provide comfortable, healthy, safe and fast quality services, save energy and labor costs, and establish a scientific management mode. To achieve the goal of architecture, it needs the joint efforts and hard work of engineering designers, construction personnel and management personnel. With the development of science and technology, as the pillar of intelligent building technology, building equipment automation system technology will continue to progress. At the same time, through the detection of BA system, the quality of BA system engineering in China will be generally improved.
intelligent building uses advanced computer technology, control technology and communication technology to provide users and managers with a complete control function, convenient data processing, centralized display and operation, safe and reliable building automation system (BA system for short). BA system adopts the distributed control technology to monitor the building equipment comprehensively and in real time, which improves the operation quality of the building equipment, reces the workload of management, and reces the energy consumption of buildings. It plays an important role in the building intelligent system. However, for a long time, the quality of BA system engineering in China has been poor, and there are not many Ba systems in normal operation. The main reason is that the detection and acceptance of BA system engineering has not been established on a scientific basis
in the past three years, in order to cooperate with the government and owners in the completion and acceptance of the intelligent system project, we have successively tested the BA system of Jiushi Fuxing building, post and Telecommunications Training Building, Shanghai Tongmao building, Volkswagen building, Shanghai Pudong Development Bank Bund 12 building, Zhaofeng Global building, Zhaofeng World Trade Building and Securities Building in Shanghai. The power supply system, cold and heat source system, air conditioning system, lighting system, water supply and drainage system, garage management system, etc. under the monitoring of BA system are tested, and the real-time performance, reliability, safety, easy operation, easy maintenance and control accuracy of BA system are evaluated as important indicators of the system. This work has promoted the BA system engineering contractor to make efforts to rectify and improve the quality of the project, which has not only achieved good social benefits, but also included the results of the work in the draft of Shanghai intelligent building series standards
1. Discussion on the detection method of BA system
the detection work of BA system should first fully understand the function and performance index of the whole system according to the engineering design documents and contract technical documents. The main documents to be provided by the owner and contractor of the tested system include system type selection demonstration, system scale and capacity, control process description, system function description and performance index, BA system structure diagram, control schematic diagram of each subsystem, BA system equipment layout and wiring diagram, power distribution box electrical schematic diagram related to BA system monitoring, field equipment installation diagram, and so on DDC station and central management workstation operator station monitoring process flow chart, central monitoring room equipment layout, BA system supply contract and engineering contract, BA system construction quality inspection record, relevant engineering design change order, BA system operation record. On this basis, according to the acceptance standard of BA system, a set of reasonable BA system detection scheme is worked out
detection is generally divided into three levels: central monitoring station, subsystem (DDC station) and field equipment (sensors, transmitters, actuators, etc.) for function detection
1.1 detection of the central monitoring station
the central monitoring station is a central processing device that collects, refreshes, controls and alarms the DDC station data of each subsystem in the building. The detection items are as follows:
observe the changes of the site status on the central monitoring station, whether the status data on the screen of the central monitoring station is constantly refreshed and its response time
through the central monitoring station to control the analog output or digital output of the subordinate system, observe whether the action of the on-site actuator or object is correct and effective, and the time when the action response returns to the central monitoring station
when a fault is created on the input side of the DDC station, observe whether there is alarm fault data logging in on the screen of the central monitoring station, and send out an audible prompt and its response time
if the central monitoring station loses power artificially, after the power transmission is restored, can the central monitoring station automatically restore all monitoring and management functions
check whether the central monitoring station gives operation authority to the operators to ensure the security of BA system. It should be confirmed by the refusal of illegal operation and ultra vires operation
whether the man-machine interface is Chinese or not, the central monitoring station screen can query, control the equipment status, observe whether the equipment operation process is intuitive and convenient, so as to verify the friendly interface
check whether the central monitoring station has the function of status self diagnosis of equipment group
check whether the display and printer of the central monitoring station can provide information about the operation time, area, number and status of all or important equipment in the form of report graph and trend graph
check whether the system provides software tools for system design, application and graphics creation
check whether the parameters of the control object set by the central monitoring station are consistent with the design accuracy
check whether the operation status data of each equipment displayed by the central monitoring station is complete and accurate
1.2 detection of subsystem
the subsystem (DDC station) is a computer monitoring system that can run independently. It continuously collects, calculates, controls and alarms the process signals of various sensors and transmitters on site, and transmits them to the database of the central monitoring station (upper computer) through the communication network for real-time display, control and alarm of the central monitoring station Alarm, printing, etc
the items of the detection subsystem are as follows:
the central monitoring station is shut down artificially to observe whether each subsystem (DDC station) can work normally
after the artificial manufacturing subsystem (DDC station) loses power, whether the subsystem can automatically restore the operation state set before power loss after power transmission is restored
the communication network between the man-made subsystem (DDC station) and the central monitoring station is interrupted, whether the field equipment maintains normal automatic operation state, and whether the central monitoring station has the fault alarm signal of DDC station logging in
to detect whether the clock of the subsystem (DDC station) is synchronized with that of the central monitoring station, so as to realize the monitoring of various subsystems (DDC station) by the central monitoring station
1.3 detection of field equipment
according to the system design monitoring requirements, the electrical signal is divided into analog quantity and switching quantity. Sensors and transmitters are devices that convert various physical quantities (temperature, humidity, pressure difference, flow, electric valve opening, liquid level, voltage and current, power, power factor, operation state, etc.) into corresponding electrical signals. The actuator is a device that works according to the control signal output by DDC. The inspection items of field equipment are as follows:
check whether the installation of sensors, transmitters, actuators and DDC boxes is standard, reasonable and easy to maintain
check whether the data and status displayed by the central monitoring station are consistent with the on-site reading and status
check whether the action or sequence of the actuator is consistent with the designed process
whether to generate alarm signal when the parameter exceeds the allowable range
whether the action of the actuator under the control of the central monitoring station is normal
1.4 function detection
BA system usually monitors building equipment by function and area. Therefore, the detection function is also performed by region. Take air conditioning and public lighting areas for example. The air conditioning area is the place where people work and rest. Under the control of BA system, the air conditioning system should provide comfortable indoor temperature and good air quality. The items for testing air conditioning and public lighting areas are as follows:
testing whether the central monitoring station can control the air conditioning system according to the schele
check whether the temperature and humidity in the air conditioning area are consistent with the data displayed in the central monitoring station
to detect whether the indoor carbon dioxide content meets the health standard
check whether the lights in public lighting area can be switched on and off and night lighting can be set according to the time program, so as to achieve the purpose of energy saving
through the detection of the above three levels and functions, we can make a comprehensive evaluation on the real-time performance, reliability, safety, easy operation, easy maintenance, installation quality and control accuracy of BA system, and put forward rectification suggestions for the existing problems. Through rectification, the tested BA system can run normally
many problems are always found in BA system engineering inspection. After a certain period of rectification, most Ba systems basically meet the functions and technical indicators listed in engineering design documents and contract technology, and the system runs well, which can achieve certain energy-saving effect. The qualified BA system is effective in monitoring the construction equipment, and the real-time response of detection, control and alarm is fast; The operation interface has the advantages of high Sinicization rate, convenient operation and maintenance, and comprehensive equipment management; The system has strict control over operators' authority and clear hierarchy; The system works reliably; The control precision of air conditioning area can meet the air conditioning design requirements
first, a small number of architectural, HVAC and electrical designers did not cooperate well in the preliminary design, so that the space of the air-conditioning box room was too small and the equipment maintenance channel was difficult to walk. Or the position of fresh air outlet is unreasonable, and the quality of fresh air is not ideal
secondly, some Ba designers are not familiar with the construction equipment and the integrity of the system, resulting in the error of sensor location equipment, and even the lack of sensors and software tools
thirdly, a few Ba designers do not have a comprehensive understanding of the operating conditions and process of the air conditioning system. As a result, the operation control mode of BA system for the air conditioning system is unreasonable, and the effective energy-saving goal is not achieved
fourthly, some construction workers did not operate according to the specifications ring the equipment installation, such as wrong wiring, wrong sensor installation position, weak connection between actuator and equipment, disordered wiring in DDC box, no protective rubber washer at the inlet and outlet of the box, and disorderly pulling of metal hose, which brought hidden dangers to the normal operation of the system
fifthly, a few property management companies failed to carry out necessary maintenance in the operation of BA system, resulting in the continuous failure of the original normal system
3. Conclusion
the purpose of BA system engineering in intelligent building is to provide comfortable, healthy, safe and fast quality services, save energy and labor costs, and establish a scientific management mode. To achieve the goal of architecture, it needs the joint efforts and hard work of engineering designers, construction personnel and management personnel. With the development of science and technology, as the pillar of intelligent building technology, building equipment automation system technology will continue to progress. At the same time, through the detection of BA system, the quality of BA system engineering in China will be generally improved.
7.
DDC / CI is a display data channel command interface (DDC / CI) for remote diagnosis and control. Look at the display button! Maybe the button on the monitor doesn't pop out, or it's stuck with the computer desk
DDC means digital display channel. It is an information channel between the host and the display, through which the physical data of the display can be directly transmitted to the host
in the system supporting DDC protocol (such as Win95 / 98 / XP system), without user intervention, the operating system can obtain information from the display and display card, and automatically match the best settings or call the set display mode. Make the display achieve the best display effect
in short, when it is turned on, the system can automatically recognize the display and automatically match the best display settings. On the contrary, when it is turned off, it can only set the display itself
extended data:
DDC controller:
all control logic is completed by micro signal processor and based on each controller. These controllers receive input signals from sensors, common contacts or other instruments, process these signals according to software programs, and then output the signals to external devices
these signals can be used to start or close the machine, open or close the valve or damper, or perform complex actions according to the program. These controllers can operate the central machine system or terminal system by hand
TheDDC controller is the core of the whole control system and the key component to realize the control function of the system. Its working process is that the controller collects real-time data through analog input channel (AI) and digital input channel (DI)
The analog signal is converted into digital signal (A / D conversion) which can be accepted by the computer, and then the operation is carried out according to a certain control law. Finally, the control signal is sent out, and the digital signal is converted into analog signal (D / a conversion), and the operation of the equipment is directly controlled through the analog output channel (AO) and digital output channel (do)reference source: network DDC / CI
reference source: network DDC controller
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