GB2473916A - Method of Operating a Control System preferably for a Fan System - Google Patents

Method of Operating a Control System preferably for a Fan System Download PDF

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Publication number
GB2473916A
GB2473916A GB1014673A GB201014673A GB2473916A GB 2473916 A GB2473916 A GB 2473916A GB 1014673 A GB1014673 A GB 1014673A GB 201014673 A GB201014673 A GB 201014673A GB 2473916 A GB2473916 A GB 2473916A
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United Kingdom
Prior art keywords
control unit
master control
databus
slave device
slave
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Granted
Application number
GB1014673A
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GB2473916B (en
GB201014673D0 (en
Inventor
Paul Clarke
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Ebm Papst UK Ltd
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Ebm Papst UK Ltd
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Publication date
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Publication of GB201014673D0 publication Critical patent/GB201014673D0/en
Publication of GB2473916A publication Critical patent/GB2473916A/en
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Classifications

    • 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
    • G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
    • G05B19/042—Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
    • G05B19/0421—Multiprocessor system
    • 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
    • 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
    • G05B2219/00—Program-control systems
    • G05B2219/20—Pc systems
    • G05B2219/22—Pc multi processor system
    • G05B2219/2231—Master slave
    • 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
    • G05B2219/00—Program-control systems
    • G05B2219/20—Pc systems
    • G05B2219/25—Pc structure of the system
    • G05B2219/25223—Slave has registers to indicate master, acknowledge, transfer address, read write
    • 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
    • G05B2219/00—Program-control systems
    • G05B2219/20—Pc systems
    • G05B2219/26—Pc applications
    • G05B2219/2614—HVAC, heating, ventillation, climate control

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Quality & Reliability (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Programmable Controllers (AREA)

Abstract

A method of operating a control system, ideally for a fan installation, has a master control unit connected to a data bus or network and a plurality of slave devices also connected to that data-bus, each slave device having a databus extender permitting the connection thereto of a further slave device. Each slave device has an initial default address and the data bus extender is turned off. The master control unit requests a response from any slave device having the default address and on a slave device responding to that request, the master control unit assigns a new address within a predefined address space and the databus extender of that slave device is then turned on. These steps are repeated until the master control unit does not determine the presence of any further slave devices. Preferably the method steps are performed on power up.

Description

FAN CONTROL SYSTEMS
This invention relates to control systems having a master control unit connected to a plurality of slave devices. In particular, this invention concerns a method of operating such a control system having a databus to which the master control unit is connected and to which any one or more slave devices may be connected, and to such a control system, per Se. The invention is primarily, though not exclusively, concerned with such control systems for electric motor-driven fan installations.
There have been many proposals for fan control systems; increasingly these are computerised, using a microcontroller in order to allow the required operating and performance characteristics to be achieved, taking into account many different variables. Typically, a microcontroller will be designed to have a fixed number of 0-10 volt or pulse width modulation (PWM) output devices. A basic design may have only one such output device, though more advanced controllers may have several separate output devices.
It is possible to design a controller having many separate control outputs but this has the disadvantage of increasing the cost of the base system, which may be unacceptable if an installation does not require so many control outputs. Further, for a system manufacturer, it is impractical to provide a large number of microcontrollers differing only in the number of output devices, so that an end user may choose the most appropriate design with exactly the required number of control outputs, for again the cost of this would be unacceptable. There is thus a need for a basic system having the ability to accommodate as many control outputs as may be needed in a cost-effective manner.
With the above in mind, one aspect of this invention provides a method of operating a control system having a master control unit connected to a databus and a plurality of slave devices any one of which may be connected to the databus and each slave device having a databus extender permitting the connection thereto of a further slave device, in which method: (a) each slave device has an initial default address and its databus extender is turned off; (b) the master control unit requests a response from any slave device having the default address; (c) the first slave device responds to the request from the master control unit and is assigned a new address in a predefined address range and the databus extender of that slave device is then turned on; and (d) steps (a) to (c) are repeated until the master control unit does not determine the presence of any further slave devices.
It will be appreciated that the method of this invention allows additional hardware output devices to be added to a master control unit as and when they are required, to provide a controller having the required number of outputs.
The software running within the master control unit is able to adapt the system to the number of slave devices connected to the databus, such that the master control unit may properly address each slave device during normal operation of the system.
Each slave device to be connected to the databus is given the same initial default address, so that it may be located by the master control unit. This facilitates manufacture of the slave devices and also the information to be packaged with the slave devices, since no separate programming of an individual address for each slave device is required, once manufactured.
Preferably, the master control unit performs the method of steps (a) to (d) at initial power-up such the master control unit may determine the number of slave devices connected to the databus and assign a dynamic address to those slave devices, as long as they are connected to the databus. Further, following the completion of step (d) at power-up, the master control unit may periodically perform the method of steps (a) to (C) during normal operation, such that if the master unit receives a response from a new slave device connected to the databus, that new slave device will be assigned an appropriate dynamic address such that the new slave device will become properly incorporated within the system. This allows the hot-plugging of new slave devices into the databus, without having to program into a slave device a valid address within the dynamic address range, before plugging the device into a databus.
The method may be used equally with a databus which has a facility to force a particular slave device to be reset to its default address, or with a databus which does not have this facility but which may force a complete reset of the entire system. Either way, the master control unit will then perform steps (a) to (c) above and so properly incorporate into the system the or each slave device not already having an address within the address space of the databus.
In addition to the slave devices given the default address before incorporation in the system, it is possible for certain slave devices to have a fixed address within the pre-defined address range. In this case, the master control unit should be programmed with the fixed addresses of such slave devices as may be connected to the databus and for the master control unit then to request a response from the expected slave devices having those programmed fixed addresses. If no response is received from those devices, operation of the master control unit may then be modified as is appropriate having regard to the configuration of the overall system.
Advantageously, the master control unit periodically requests responses from all of the devices to which addresses within the pre-defined address range have been assigned, and also from those devices having fixed addresses, to check for the continued presence of each device on the databus. In the event that no response is received from any one or more of those devices which previously had been determined as being present, the master control unit may thereafter take the appropriate action having regard to the nature of the device no longer, or apparently no longer, present. Apart from allowing devices to be removed without an entire system reset, the master control unit may be arranged to raise alarms, fault warnings or other such action in the event that a device is noted as no longer present.
The slave devices are in effect daisy-chained together (though there may be a plurality of separate daisy chains each having a multiplicity of slave devices) and each device after the first requires the continued existence of the preceding device or devices to ensure its continued control by the master control unit. In the event that a device higher up the daisy chain fails, the master control unit may not be able to continue controlling the operation of devices below the failed device. It is therefore preferred that the slave devices are able to continue operating in their last set states or if configured to do so.
operate in a specific manner in response to the fault, in the event that the slave device becomes disconnected from the master control unit. This will also allow the slave devices to continue in operation should the master control unit itself fail or should a slave device higher up the chain be removed from the databus, until such time as the master control unit requests responses from the expected slave devices and then adjusts the installation operation to accommodate the removal of that slave device.
Though the method of operating the control system is primarily intended for use with a control system for an electric motor-driven fan installation, it will be appreciated that the method may be employed with other control systems where there are slave devices connected to a databus also having a master control unit connected thereto.
According to a second aspect of this invention there is provided a control system for an electric motor-driven fan installation, which control system comprises a master control unit, a plurality of slave devices and a databus linking the master control unit and slave devices, in which system at least one of the connected slave devices is able to continue operating in its last set state or if configured to do so operate in a specific manner in response to the fault, in the event that the slave device becomes disconnected from the master control unit.
By way of example only, one specific embodiment of control system for an electric motor-driven fan system arranged in accordance with this invention will now be described in detail, reference being made to the accompanying drawings in which:-Figure 1 diagrammatically shows the overall configuration for the embodiment of control system; and Figure 2 diagrammatically illustrates the sub-system configuration.
As shown in Figure 1, the fan control system of this invention is adapted for connection to the Internet or an intranet, such that the control system may be operated remotely from the actual installation itself. The system comprises a logging server and a display server both of which use TCP/IP to allow data to be transmitted over the Internet or intranet. The two servers use RS485 to communicate with individual master control units (each of which is referred to hereinafter as an MCU but each of which is identified in Figure 1 as a "Generic Controller") -and in this particular example, there are six MCU5. Daisy-chained from each MCU are four separate slave devices linked together by way of a databus and in this example, these four slave devices are identified as "General Slave", "Display LED", "Sensor Temp NTC" and "Valve driver".
Referring now to Figure 2, the sub-system of this embodiment is shown in more detail and it can be seen that the MCU (identified in Figure 2 as "Master Device") drives a databus to which are connected three slave devices, arranged in series. Following the third slave device there are twenty-six additional slave devices all arranged in series on the databus. These additional slave devices are arranged in groups and in this embodiment, these groups consist of displays, sensors, I/O devices, drivers, communication devices and other miscellaneous devices including power supplies, storage devices and a real-time clock.
Each of the slave devices shown in Figure 2 is similarly configured so far as the address bus is concerned, in that at manufacture, each slave device is given the same default address. Further, each slave device has a databus is extender which, as manufactured, is turned off. When the system is assembled, at power-up the MCU (the "Master Device" in Figure 2) requests a response from a device having the default address. That response is provided by the first slave device on the databus and the other slave devices will not respond since the databus extender of the first device is turned off.
On receiving a response from the first slave device, the MCU assigns to that first slave device a dynamic address in a pre-defined address range and also turns on the databus extender of that first slave device. The MCU then repeats the request for a response from a device having the default address and will receive a response from the second slave device on the databus. This is then assigned the next dynamic address in the pre-defined address range and the databus extender of that second slave device is turned on. This process is repeated until no response is received from any device having the default address, at which point the MCU will have assigned a different dynamic address to each slave device on the databus.
An exception to the above may be in the case of certain slave devices required to perform particular functions. For example, there may be an advantage in having the first slave device on the databus with a fixed address, or perhaps the first few slave devices with fixed but different addresses, rather than dynamically assigned addresses assigned by the MCU. In this case, each such device may be programmed to have a fixed address and the MCU should be programmed expressly to request a response from the fixed address as a part of the power-up sequence of operation.
Though not shown in the drawings, each slave device is connected into the overall installation in order to control a function for which that slave device was designed. Figure 2 gives examples of such functions by way of the labelling of the slave devices, though these are not exhaustive and there may be different functionality provided by other slave devices.
It will be appreciated that the system as described above and having a databus together with a MCU which assigns dynamic addresses to slave devices allows the overall system to be self-healing, hot-pluggable and, provided each slave device is suitably configured, allows continued operation (though perhaps in a more limited form) in the event that one or more slave devices, the databus or even the MCU itself fails.

Claims (12)

  1. CLAIMS1. A method of operating a control system having a master control unit connected to a databus and a plurality of slave devices any one of which may be connected to the databus and each slave device having a databus extender permitting the connection thereto of a further slave device, in which method: (a) each slave device has an initial default address and its databus extender is turned off; (b) the master control unit requests a response from any slave device having the default address; (c) the first slave device responds to the request from the master control unit and is assigned a new address in a predefined address range and the databus extender of that slave device is then turned on; and (d) steps (a) to (c) are repeated until the master control unit does not determine the presence of any further slave devices.
  2. 2. A method as claimed in claim 1, in which the master control unit performs the method of steps (a) to (d) at power-up.
  3. 3. A method as claimed in claim 1, in which the master control unit performs the method of steps (a) to (c) periodically following completion of step (d) at power-up, and if the master control unit receives a response from a new slave device connected to the databus, the master control unit repeats those steps (a) to (c) until no new slave device is found.
  4. 4. A method as claimed in any of claims 1 to 3, in which the master control unit is arranged to request a response from a further slave device having a fixed address within the predefined address range.
  5. 5. A method as claimed in claim 4, in which the master control unit is programmed with the fixed addresses of such further slave devices as may be connected to the databus and requests responses from each of the programmed fixed addresses.
  6. 6. A method as claimed in any of the preceding claims, in which the master control unit periodically requests responses from all of the devices to which addresses within the defined address range have been assigned, to check for the continued presence of each device on the databus.
  7. 7. A method as claimed in any of the preceding claims, wherein at least one of the connected slave devices is able to continue operating in its last set state in the event that the slave device becomes disconnected from the master control unit.
  8. 8. A method as claimed in any of the preceding claims, wherein the databus is arranged to permit a chosen slave device to be re-set to its default address whereafter the master control unit performs steps (a) to (c) to incorporate into the system the chosen slave device.
  9. 9. A method as claimed in any of the preceding claims, wherein the databus is arranged to permit an entire system re-set so that all of the slave devices are re-set to their default addresses whereafter the master control unit performs steps (a) to (c) to incorporate into the system all of the slave devices.
  10. 10. A method as claimed in any of the preceding claims, wherein the master control unit and the connected slave devices are configured as a control system for an electric motor-driven fan installation.
  11. 11. A control system for an electric motor-driven fan installation, which control system comprises a master control unit, a plurality of slave devices and a databus linking the master control unit and slave devices, in which system at least one of the connected slave devices is able to continue operating in its last set state or if configured to do so operate in a specific manner in response to -10-the fault, in the event that the slave device becomes disconnected from the master control unit.
  12. 12. A method of operating a control system as claimed in claim 1 and substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.
GB1014673.6A 2009-09-23 2010-09-03 Fan control systems Active GB2473916B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0916717A GB0916717D0 (en) 2009-09-23 2009-09-23 Fan control systems

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GB2473916A true GB2473916A (en) 2011-03-30
GB2473916B GB2473916B (en) 2015-04-08

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GB0916717A Ceased GB0916717D0 (en) 2009-09-23 2009-09-23 Fan control systems
GB1014673.6A Active GB2473916B (en) 2009-09-23 2010-09-03 Fan control systems

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3007387B1 (en) 2014-10-10 2017-08-09 ebm-papst Mulfingen GmbH & Co. KG Dynamically addressable master slave system and method for dynamic addressing of slave units
CN112161393A (en) * 2020-08-28 2021-01-01 珠海格力电器股份有限公司 Method and device for customizing functions of household appliance, electronic equipment and storage medium

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US5805926A (en) * 1994-05-31 1998-09-08 Sgs-Thomson Microelectronics, S.A. System for controller maintains table showing actuators and sensors and accordingly assigning addresses and adds to table if actuators and sensors were added during same time
EP0939922A1 (en) * 1997-09-13 1999-09-08 Lindauer Dornier Gesellschaft M.B.H Device and method for controlling machines especially a power loom
EP1503262A2 (en) * 2003-07-31 2005-02-02 E.G.O. ELEKTRO-GERÄTEBAU GmbH Method for dynamic assignment of addresses as well as associated use for heating apparatuses
WO2005062140A2 (en) * 2003-12-22 2005-07-07 Vega Grieshaber Kg Method and system for automated configuring of a hart multi-drop system
US20090193166A1 (en) * 2006-06-01 2009-07-30 Wolfgang Kropp Device and method for addressing, and converter
US20090271001A1 (en) * 2008-04-28 2009-10-29 Kmc Controls, Inc. BACnet Protocol MS/TP Automatic MAC Addressing

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CA2177941A1 (en) * 1996-05-31 1997-12-01 Francois Routhier Fail-safe networked control system for ventilation units
US7013328B2 (en) * 2001-11-27 2006-03-14 Baumuller Anlagen-Systemtechnik Gmbh & Co. Electrical drive system with drive unit networks, intercommunication networks and multi-link-controller
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Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5805926A (en) * 1994-05-31 1998-09-08 Sgs-Thomson Microelectronics, S.A. System for controller maintains table showing actuators and sensors and accordingly assigning addresses and adds to table if actuators and sensors were added during same time
EP0939922A1 (en) * 1997-09-13 1999-09-08 Lindauer Dornier Gesellschaft M.B.H Device and method for controlling machines especially a power loom
EP1503262A2 (en) * 2003-07-31 2005-02-02 E.G.O. ELEKTRO-GERÄTEBAU GmbH Method for dynamic assignment of addresses as well as associated use for heating apparatuses
WO2005062140A2 (en) * 2003-12-22 2005-07-07 Vega Grieshaber Kg Method and system for automated configuring of a hart multi-drop system
US20090193166A1 (en) * 2006-06-01 2009-07-30 Wolfgang Kropp Device and method for addressing, and converter
US20090271001A1 (en) * 2008-04-28 2009-10-29 Kmc Controls, Inc. BACnet Protocol MS/TP Automatic MAC Addressing

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3007387B1 (en) 2014-10-10 2017-08-09 ebm-papst Mulfingen GmbH & Co. KG Dynamically addressable master slave system and method for dynamic addressing of slave units
CN112161393A (en) * 2020-08-28 2021-01-01 珠海格力电器股份有限公司 Method and device for customizing functions of household appliance, electronic equipment and storage medium

Also Published As

Publication number Publication date
GB0916717D0 (en) 2009-11-04
GB2473916B (en) 2015-04-08
GB201014673D0 (en) 2010-10-20

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