CN113028615A - Distributed central air-conditioning system based on CAN bus and control method thereof - Google Patents
Distributed central air-conditioning system based on CAN bus and control method thereof Download PDFInfo
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- CN113028615A CN113028615A CN201911255185.XA CN201911255185A CN113028615A CN 113028615 A CN113028615 A CN 113028615A CN 201911255185 A CN201911255185 A CN 201911255185A CN 113028615 A CN113028615 A CN 113028615A
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- 238000004378 air conditioning Methods 0.000 title claims abstract description 33
- 238000000034 method Methods 0.000 title claims abstract description 23
- 238000004891 communication Methods 0.000 claims abstract description 11
- 238000001514 detection method Methods 0.000 claims description 16
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 230000005540 biological transmission Effects 0.000 abstract description 3
- 238000013461 design Methods 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/89—Arrangement or mounting of control or safety devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F11/00—Control or safety arrangements
- F24F11/30—Control or safety arrangements for purposes related to the operation of the system, e.g. for safety or monitoring
- F24F11/32—Responding to malfunctions or emergencies
- F24F11/38—Failure diagnosis
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/418—Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM]
- G05B19/4183—Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM] characterised by data acquisition, e.g. workpiece identification
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/418—Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM]
- G05B19/4185—Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS] or computer integrated manufacturing [CIM] characterised by the network communication
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Quality & Reliability (AREA)
- Mechanical Engineering (AREA)
- Combustion & Propulsion (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Air Conditioning Control Device (AREA)
Abstract
The invention provides a distributed central air-conditioning system based on a CAN bus and a control method thereof. The upper computer is connected with a CAN bus through an intelligent CAN bus communication adapter card inserted in the PC bus expansion slot and is connected with the unit controllers of the lower computers through the CAN bus. And the unit controller of the lower computer can be separated from the upper computer to directly carry out field manual control. The invention adopts a distributed control mode based on the CAN bus to increase the transmission distance and achieve the aims of improving the real-time performance, the reliability and the control efficiency of remote control.
Description
Technical Field
The invention belongs to the technical field of energy conservation, and particularly relates to a distributed central air-conditioning system based on a CAN bus and a control method thereof.
Background
The central air conditioning system consists of air heating, cooling, humidifying, dehumidifying, air purifying and air volume regulating equipment, cold and heat source for air conditioner and other equipment. The capacity of these devices is generally the design capacity, but the actual load in daily operation is part of the load for most of the time and does not reach the design capacity. Therefore, for comfort and energy saving, the above devices must be controlled so that their actual output is compatible with the actual load. In a central air conditioning system, the controlled parameters mainly include the temperature, humidity, pressure, air freshness, airflow direction, etc. of air. The central air-conditioning automatic control system automatically controls the temperature, the relative humidity, the freshness and the like of indoor air, keeps the optimal quality of the air, enables people to live and work in the environment and is comfortable, and therefore the working efficiency can be greatly improved, and the central air-conditioning control system is an indispensable component in an intelligent building. The traditional control method of the central air conditioner is to adopt a DDC (direct digital controller) mode to connect each temperature and control point to one or more DDCs (direct digital controllers) and realize multi-point real-time monitoring. Because modern intelligent building floor is more, and a plurality of air conditioner fans are located different floors, and the temperature monitoring point distributes in each room, adopts the DDC mode to control and has the lead wire overlength, and the construction is inconvenient, the real-time and the reliability of system communication are not high etc. shortcoming.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a distributed central air-conditioning system based on a CAN bus and a control method thereof, which adopt a distributed control mode based on the CAN bus to increase the transmission distance and achieve the purposes of improving the real-time performance, the reliability and the control efficiency of remote control.
The invention provides a distributed central air-conditioning system based on a CAN bus, which comprises an upper computer and a plurality of lower computers, wherein the upper computer and each lower computer are communicated through the CAN bus.
Preferably, the upper computer is connected with a CAN bus through an intelligent CAN bus communication adapter card inserted in the PC bus expansion slot and is connected with the unit controller of each lower computer through the CAN bus.
Preferably, the unit controller of the lower computer can be separated from the upper computer to directly perform field manual control.
Preferably, the lower computers all adopt AT89C51 single-chip microcomputers as microprocessors; the upper computer adopts an IBM-PC compatible machine.
Preferably, the specific control of the lower computer comprises air inlet temperature detection, air return temperature detection, average current detection, motor rotating speed detection, fault information receiving, distance control judgment, local setting and temperature display.
The invention also provides a control method of the distributed central air-conditioning system based on the CAN bus, which comprises the following steps:
the method comprises the following steps: control information is input through an upper computer, and the upper computer sends the control information to each lower computer through a CAN bus;
step two; and the corresponding lower computer detects the temperature information and combines the rotation speed of the given control fan.
Further, the method also comprises the third step of: when each lower computer is separated from the upper computer, a worker directly sets given control information by the lower computer manually and independently and automatically controls the air conditioner fan.
Preferably, the second step specifically includes the following steps:
step 1: initializing a lower computer;
step 2: after initialization is completed or interrupted, receiving a control information instruction given by an upper computer through a CAN bus;
and step 3: carrying out A/D conversion on the acquired control information;
and 4, step 4: judging a far/near selection switch according to the converted control information;
and 5: and (3) determining a far-near end given mode and a control command, executing the operation of the lower computer, receiving a fault signal, feeding the fault signal back to the upper computer, returning to the step 2, and receiving and executing the control information of the next round.
Preferably, the control information in step 3 includes control information given by the CAN bus mode, and also includes control information directly operated on the lower computer in a manual mode.
Preferably, in the step 5, the control quantity of the PI regulation unit is U and the control quantity is adjusted to U + Δ U according to the control command, where Δ U is the control quantity adjustment quantity, a/D conversion is performed to output the execution control command, then the fault signal is received in a serial communication manner, and finally the execution result of the control command and the content of the fault signal are returned to the upper computer through the CAN bus, and the control command CAN be displayed by the LED.
The invention has the advantages that:
the invention provides a distributed central air-conditioning system based on a CAN bus and a control method thereof, which increase the transmission distance by adopting a distributed control mode based on the CAN bus and achieve the purposes of improving the real-time performance, the reliability and the control efficiency of remote control. The optimization method also has the characteristic of easy node increase, and the CAN bus is used as a field bus with international standard, and has the characteristics of reliable data communication, good real-time performance and flexibility.
Drawings
FIG. 1 is a schematic diagram of a distributed central air conditioning system based on a CAN bus;
fig. 2 is a flow chart of the control of the lower computer nodes in the control method of the distributed central air conditioning system according to the present invention.
Detailed Description
In the following, only certain exemplary embodiments are briefly described. As those skilled in the art can appreciate, the described embodiments can be modified in various different ways, without departing from the spirit or scope of the present disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.
In the description of the present disclosure, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "straight", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore should not be considered as limiting the present disclosure. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present disclosure, "a plurality" means two or more unless specifically limited otherwise.
Throughout the description of the present disclosure, it is to be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection, either mechanically, electrically, or otherwise in communication with one another; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present disclosure can be understood by those of ordinary skill in the art as appropriate.
In the present disclosure, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise the first and second features being in direct contact, or may comprise the first and second features being in contact, not directly, but via another feature in between. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly above and obliquely above the second feature, or simply meaning that the first feature is at a lesser level than the second feature.
The preferred embodiments of the present disclosure will be described below with reference to the accompanying drawings, and it should be understood that the preferred embodiments described herein are merely for purposes of illustrating and explaining the present disclosure and are not intended to limit the present disclosure.
The invention is realized by the following technical scheme:
the invention provides a CAN bus-based distributed central air-conditioning system optimization method, wherein the overall frame diagram of the distributed central air-conditioning system is shown in figure 1, and an upper computer of the distributed central air-conditioning control system adopts an IBM-PC compatible machine and is responsible for receiving and managing system data, sending control commands, displaying the working process of the system in real time and the like. The distributed central air-conditioning control system comprises a plurality of lower computers, wherein each lower computer adopts an AT89C51 single chip microcomputer of ATMEL company as a microprocessor and is responsible for signal acquisition in the unit, control of an air-conditioning fan, display of working state and temperature and the like. And a CAN bus controller SJA1000 in the unit controller of the lower computer is responsible for receiving data from a CAN bus and sending the data to the upper computer through a CANz bus. The lower computer can receive a control command of the upper computer to perform operations such as air inlet temperature detection, air return temperature detection, average current detection, motor rotating speed detection, fault information reception, distance control, local setting, temperature display and the like. The upper computer is connected with a CAN bus through an intelligent CAN bus communication adapter card inserted in the PC bus expansion slot and is connected with the unit controllers of the lower computers through the CAN bus. The unit controller of each lower computer can also be separated from the upper computer to directly carry out on-site manual control.
The control method of the distributed central air-conditioning system specifically comprises the following steps: the staff inputs control information through the PC, and the host computer sends the control instructions to each lower computer through the CAN bus. And the lower computer detects the temperature information and combines the rotation speed of the given control fan. If the air conditioner fan is separated from the upper computer, a worker can directly and manually set given control information by the lower computer and independently automatically control the air conditioner fan. The specific control of the lower computer comprises air inlet temperature detection, air return temperature detection, average current detection, motor rotating speed detection, fault information receiving, distance control judgment, local setting and temperature display.
The distributed central air conditioning system CAN be remotely controlled by an upper computer through a CAN bus and CAN also be directly controlled on site. The distributed central air-conditioning system also has better expansion margin, and can expand the nodes of the lower computers according to the application requirements. The debugging experiment of the prototype of the distributed central air-conditioning system proves that the distributed central air-conditioning system has reasonable design, reliable work, high cost performance, low development cost, strong practical application value and wide prospect.
The node control flow chart of the lower computer in the distributed central air-conditioning system is shown in fig. 2, wherein the lower computer node mainly completes the functions of data acquisition, data communication, I/O interface control, digital display control and the like. The control parameters are set in real time according to the setting of an upper computer, so that the speed of the motor is regulated. And the lower computer can also be separated from the upper computer to carry out on-site given operation through a small keyboard on a node of the lower computer. And a far/near selection switch is arranged on the lower computer node. The state of the selection switch is judged in each control period in the whole process, so that the setting is determined. The setting of the selection switch enables a user to set the temperature of the whole lower computer in the master control room through the upper computer, and can also directly set the lower computer in the room according to the specific requirements of the user. And the lower computer node control board is also provided with an LED display lamp which can display parameters such as set temperature in real time.
The node control flow of the lower computer mainly comprises the following steps:
step 1: initializing a lower computer;
step 2: after initialization is completed or interrupted, receiving a control information instruction given by an upper computer through a CAN bus;
and step 3: carrying out A/D conversion on control information acquired in various modes, wherein the control information covers control information given by a CAN bus mode and also comprises control information directly operated on a lower computer in a manual mode;
and 4, step 4: judging a far/near selection switch according to the converted control information;
and 5: determining a far-end given mode and a near-end given mode and a control command, displaying an LED (such as set temperature), adjusting the control quantity of a PI (proportional integral) regulating unit to be U according to the control command, adjusting the control quantity to be U plus delta U (delta U is the control quantity adjustment quantity), performing A/D (analog to digital) conversion, outputting and executing the control command, receiving a fault signal in a serial communication mode, returning a control command execution result and the content of the fault signal to an upper computer through a CAN (controller area network) bus, and returning to the step 2 again to receive the control information of the next round.
The above description is only exemplary of the present disclosure and should not be taken as limiting the disclosure, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present disclosure should be included in the scope of protection of the present disclosure.
Finally, it should be noted that: although the present disclosure has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the disclosure. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.
Claims (10)
1. The distributed central air-conditioning system based on the CAN bus is characterized by comprising an upper computer and a plurality of lower computers, wherein the upper computer and the lower computers are communicated through the CAN bus.
2. The CAN-bus based distributed central air conditioning system of claim 1, wherein the upper computer is connected with the CAN bus through an intelligent CAN bus communication adapter card inserted in the PC bus expansion slot and is connected with the unit controller of each lower computer through the CAN bus.
3. The CAN bus-based distributed central air conditioning system of claim 1, wherein the unit controller of the lower computer CAN be directly controlled manually on site without being separated from the upper computer.
4. The CAN bus-based distributed central air conditioning system according to claim 1, wherein the lower computers all use an AT89C51 single chip microcomputer as a microprocessor; the upper computer adopts an IBM-PC compatible machine.
5. The distributed central air-conditioning system based on CAN bus of claim 1, wherein the specific control of the lower computer includes air inlet temperature detection, air return temperature detection, average current detection, motor speed detection, fault information reception, distance control judgment, local setting and temperature display.
6. A control method of a distributed central air-conditioning system based on a CAN bus is characterized by comprising the following steps:
the method comprises the following steps: control information is input through an upper computer, and the upper computer sends the control information to each lower computer through a CAN bus;
step two; and the corresponding lower computer detects the temperature information and combines the rotation speed of the given control fan.
7. The control method of the distributed central air conditioning system based on CAN bus according to claim 6, further comprising the third step of: when each lower computer is separated from the upper computer, a worker directly sets given control information by the lower computer manually and independently and automatically controls the air conditioner fan.
8. The method as claimed in claim 6, wherein the step two includes the following steps:
step 1: initializing a lower computer;
step 2: after initialization is completed or interrupted, receiving a control information instruction given by an upper computer through a CAN bus;
and step 3: carrying out A/D conversion on the acquired control information;
and 4, step 4: judging a far/near selection switch according to the converted control information;
and 5: and (3) determining a far-near end given mode and a control command, executing the operation of the lower computer, receiving a fault signal, feeding the fault signal back to the upper computer, returning to the step 2, and receiving and executing the control information of the next round.
9. The CAN-bus based distributed central air-conditioning system control method of claim 8, wherein said control message in step 3 includes the control message given by CAN-bus mode and also includes the control message directly operated on the lower computer by manual mode.
10. The method as claimed in claim 8, wherein the step 5 is performed by setting the control amount of the PI controller to U and adjusting the control amount to U + Δ U according to the control command, wherein Δ U is the control amount adjustment amount, performing a/D conversion to output the execution control command, receiving the fault signal through a serial communication method, and finally returning the execution result of the control command and the content of the fault signal to the upper computer through the CAN bus, wherein the control command CAN be displayed by an LED.
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CN201911255185.XA CN113028615A (en) | 2019-12-09 | 2019-12-09 | Distributed central air-conditioning system based on CAN bus and control method thereof |
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN202835671U (en) * | 2012-08-27 | 2013-03-27 | 宁波奥克斯空调有限公司 | Household air conditioner control system based on controller area network (CAN) bus |
CN104728988A (en) * | 2013-12-18 | 2015-06-24 | 珠海格力电器股份有限公司 | Air conditioner and communication method, device and equipment for indoor unit and outdoor unit of air conditioner |
CN108332394A (en) * | 2018-01-08 | 2018-07-27 | 江苏万全智能环境设备有限公司 | Indoor electric appliance coordinated control system based on Internet of Things and its control method |
US20190203967A1 (en) * | 2016-04-15 | 2019-07-04 | Belimo Holding Ag | Control adapter for fastening on a device of an hvac system |
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2019
- 2019-12-09 CN CN201911255185.XA patent/CN113028615A/en active Pending
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN202835671U (en) * | 2012-08-27 | 2013-03-27 | 宁波奥克斯空调有限公司 | Household air conditioner control system based on controller area network (CAN) bus |
CN104728988A (en) * | 2013-12-18 | 2015-06-24 | 珠海格力电器股份有限公司 | Air conditioner and communication method, device and equipment for indoor unit and outdoor unit of air conditioner |
US20190203967A1 (en) * | 2016-04-15 | 2019-07-04 | Belimo Holding Ag | Control adapter for fastening on a device of an hvac system |
CN108332394A (en) * | 2018-01-08 | 2018-07-27 | 江苏万全智能环境设备有限公司 | Indoor electric appliance coordinated control system based on Internet of Things and its control method |
Non-Patent Citations (1)
Title |
---|
黄勤陆等: "《智能楼宇与网络工程》", 31 January 2017 * |
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Application publication date: 20210625 |