Abstract:
An interface is disclosed that is locatable between a server and at least one operational system for a clean room. The interface has a memory configured to store a copy of control settings from a control signal sent from the server to the at least one operational system; and a processor configured to send a control signal to the at least one operational system based on the stored copy of the control settings, if a predetermined condition is met.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to a control system and an interface therefore and refers particularly, though not exclusively, to a control system and an interface therefor between a server and at least one operational system for a clean room or a clean zone. 
       BACKGROUND 
       [0002]    In certain manufacturing processes it is desirable to reduce the level of airborne containments. For example, in semiconductor manufacturing or laboratories it is common to use “clean rooms” where the level of airborne contaminants is below a strict standard. For example Federal Standard 209E developed by the U.S. General Services Administration and ISO 14644-1/2 developed by the International Organization for Standardization establish standard classes of air cleanliness for airborne particulate levels in clean rooms and clean zones. 
         [0003]    An example of a prior art clean room  100  is shown in  FIG. 1 . A substantially sealed interior  102  is provided with clean air from a series of fan filter units (“FFUs)  104  mounted on or in the ceiling  105 . Each FFU  104  receives air from the air supply system  106 . Each FFU  104  has at least one filter to remove contaminants from the air. The filter may be, for example a High Efficiency Particulate Air (HEPA) filter and/or Ultra Low Penetration Air (ULPA) filter. The flow through the filter into the interior  102  is controlled by a fan. The fan preferably generates a laminar flow through the filter. The fan may be driven by a variable speed AC or DC motor. 
         [0004]    The FFUs  104  are typically operated to create a pressure in the interior  102  which is higher than the pressure of the exterior  108  and the air supply system  106 . This overpressure prevents any “dirty” air or contamination from outside  108  or from the within the air supply system  106  from leaking into the interior  102 . The higher the pressure difference, the lower is the chance of contamination. 
         [0005]    There are many reasons why a given FFU  104  may produce a lower than expected airflow. The most common reason is that the filter is blocked. What ever the reason, if the required airflow is not generated the pressure in the clean room may drop. That means there is a higher chance of contamination. 
         [0006]    Also, in an installation where there are a large number of FFUs, the situation in one region of the installation may be different to that in another region. For example, one region may suffer from an output of a gas or other atmospheric contaminant. In that case the particular region may require the FFUs to be switched off very quickly to minimize distribution of the gas. 
         [0007]    An example of a prior art clean room control system  200  is shown in  FIG. 2(   a ). Each FFU  104  is connected via a network  206  and an associated protocol converter/gateway  208  to a server  210 . The server  210  in turn may be connected to one or more client terminals  212  via a network  214 . The FFUs  104  may be arranged in groups with there being two or more FFUs in each group. Each group has a gateway  208 . Protocol conversion in a gateway  208  may be required if the instructions for the FFUs in the relevant group are in a format or protocol not suitable for the FFUs. 
         [0008]    The overall pressure in the room may be set and/or monitored using the client terminals and software loaded on the server. The software may allow the speeds of individual FFUs to be set if desired, and the actual speed detected by the sensor may be able to be logged. The software accordingly controls each FFU through the network to deliver the desired performance. 
         [0009]    However in the event of a network or hardware failure, control of the FFUs will be lost. The only alternative it is to connect an individual manual controller to each FFU, which can be very time consuming, and may result in contamination. Also, urgent localized control of an individual FFU, or a group of FFUs, is not possible. This is also applicable to other operational systems of the clean room including, but not limited to: air showers, building management system, lighting system, alarm system, security system, temperature control system, and air flow control system. 
       SUMMARY 
       [0010]    In general terms in a first aspect the invention proposes that in a clean room control system each gateway is an interface that locally stores the control settings which are synchronised with the central server. This may have the advantage that the interface can operate each operational system according to the locally stored settings. 
         [0011]    In a second independent aspect in a clean room control system each interface may have a control panel that allows local control of the operational system. This may have the advantage that the interface can operate each operational system according to localized user settings. 
         [0012]    In a first exemplary aspect there is provided an interface between a server and at least one operational system for a clean room, the interface comprising: 
         [0013]    a memory configured to store a copy of control settings from a control signal sent from the server to the at least one operational system; and 
         [0014]    a processor configured to send a control signal to the at least one operational system based on the stored copy of the control settings, if a predetermined condition is met. 
         [0015]    The interface may further comprise a user interface configured to receive user settings; and the processor may be configured to send a control signal to the at least one operational system based on at least one of: the stored copy of the control settings, and the user settings. The at least one operational system may be at least one of: a plurality of fan filter units, an air shower system, building management system, lighting system, alarm system, security system, temperature control system, and air flow control system. The user settings may be for one of: a single fan filter unit, a lesser plurality of fan filter units, a group of fan filter units, and a plurality of groups of fan filter units. 
         [0016]    According to a second exemplary aspect there is provided an interface between a server and at least one operational system for a clean room or a clean zone, the interface comprising: 
         [0017]    a user interface configured to receive user settings; 
         [0018]    a memory configured to store control settings receivable from a server; and 
         [0019]    a processor configured to send a control signal to the at least one operational system based on at least one of: the stored control settings, and the user settings, if a predetermined condition is met. 
         [0020]    For both aspects, the at least one operational system may be at least one of: a plurality of fan filter units, an air shower system, building management system, lighting system, alarm system, security system, temperature control system, and air flow control system. The user settings may be for one of: a single fan filter unit, a lesser plurality of fan filter units, a group of fan filter units, and a plurality of groups of fan filter units. The plurality of fan filter units may be arranged in a manner selected from: as single fan filter units, a group of fan filter units, and a plurality of groups of fan filter units. 
         [0021]    The predetermined condition may relate to a communication failure between the server and the interface, or local control of the interface being enabled. 
         [0022]    The control signal may be configured to operate in a first protocol and the processor may be further configured to convert the control signal from the server to a control signal having a second protocol. The interface may further comprise a port configured to receive a protocol converter and wherein the protocol converter is for converting the first protocol to the second protocol. 
         [0023]    The user interface may comprise a touch screen. The memory may be connected to the processor. 
         [0024]    According to a third exemplary aspect there is provided a control system for at least one operational system comprising at least one interface as described above. 
         [0025]    There may be a plurality of interfaces. The plurality of interfaces may be located between the server and the at least one operational system. The at least one operational system may be operatively connectable to the plurality of interfaces by an operational system network. Each interface further may comprise a first network interface for receiving the control signal and the control settings, and a second network interface connectable to the operational system network. The stored copy of the control signals may be a copy of the last received control signals. The user settings may override the control settings. The at least one operational system may be at least one of: a plurality of fan filter units, an air shower system, building management system, lighting system, alarm system, security system, temperature control system, and air flow control system. 
         [0026]    For all aspects the user settings may be for at least one of: a plurality of fan filter units, an air shower system, building management system, lighting system, alarm system, security system, temperature control system, and air flow control system. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    In order that the invention may be fully understood and readily put into practical effect there shall now be described by way of non-limitative example only preferred embodiments of the present invention, the description being with reference to the accompanying illustrative drawings. 
           [0028]    In the drawings: 
           [0029]      FIG. 1  is a schematic diagram of a prior art clean room; 
           [0030]      FIG. 2(   a ) is a block diagram of a prior art control system; 
           [0031]      FIG. 2(   b ) is a block diagram of an exemplary embodiment of an FFU motor speed controller; 
           [0032]      FIG. 3  is a block diagram of a control system according to an exemplary embodiment; 
           [0033]      FIG. 4  is a block diagram of the interface in  FIG. 3 ; 
           [0034]      FIG. 5  is a flow diagram of the operation of the interface of  FIG. 4 ; and 
           [0035]      FIG. 6  is a block diagram of a control system according to another exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0036]      FIGS. 2(   b ) and  3  show a control system  300  for a clean room according to an exemplary embodiment. Each FFU or group of FFUs  204 ,  304  is connected via an FFU network  306  to an associated control interface  308 . Each interface  308  may be for a single FFU, a single group of FFUs, a plurality of FFUs, or a plurality of groups of FFUs. Each interface  308  is connected to a server  310 . The server  310  may be connected to one or more client terminals  312  via a network  314 . Each interface  308  may have an associated control panel  316 . 
         [0037]    A master motor controller  203  is provided for each FFU, group of FFUs or groups of FFUs, as shown in  FIG. 2(   b ). The motor controller for each FFU may have open loop or closed loop control via a sensor (not shown), may control based on a desired motor speed, desired air flow, or desired pressure, and may be as simple as a variable voltage applied to the motor windings (e.g.: for a DC motor), or more complicated variable frequency drives (for Induction or PMAC drives). 
         [0038]    Referring to  FIG. 4 , the control panel  316  is shown in more detail. A processor  400  is connected to a touch panel  402  that may be of any suitable form such as, for example, an LCD touch panel. The processor  400  is also connected to a memory  404 . A first network interface  406  receives data from the server network  314  and/or other interfaces. A second network interface  408  connects to the FFU network  306 . A port  410  is used to connect an interchangeable protocol converter  412  (a different converter is connected to the port depending on the protocol of the FFU network). Both network interfaces are connected to the processor  402  and to the protocol converter  412 . Protocol compliance card  412  performs all the necessary protocol conversion so the FFUs  304  can act on the received instructions. By having a protocol compliance card slot  410  and a range of protocol compliance cards, the one control panel can be used for a large range of FFUs and servers  310 , and separate control panels for different FFUs  304 /servers  310  will not be required. If the operating system of server  310  is changed, all that need be changed is the protocol compliance card  412  for each interface  308  to maintain the system operative. The external connections (not shown) include an Ethernet connection to the server, RS485 ports for connection to the FFU groups and a power supply connection. A power supply  414  such as, for example, an uninterrupted power supply, may be provided to supply power to the control panel  316 . 
         [0039]    The operation of the interface  308  is shown in more detail in  FIG. 5 . In normal server control mode the FFUs  304  are controlled by the server  310 . At the interface  308 , communication with the server  310  is checked to determine whether the server  310  is connected and functioning correctly (communication test step  502 ). If the server  310  is connected, a synchronised copy of the control settings from the server  310  is periodically stored in the interface memory  404  (synchronisation step  504 ). The interface memory  404  includes a register storing whether or not local control is enabled from the LCD touch panel  402  (local control test step  506 ). In normal server control mode (if the server  310  is connected and local control is not enabled) the protocol converter  412  converts the control signals from the server network protocol e.g.: TCP/IP, into the appropriate protocol for the FFU network  306  e.g.: RS485 or LONWORKS (conversion step  508 ). 
         [0040]    If communication with the server  310  is lost for any reason, or if local control is enabled, local control immediately commences. The processor  400  generates the control signals to operate the FFUs  304  from the settings stored in the interface memory  404  (local control step  510 ). Initially these settings are the last stored synchronised settings as received from the server  310  before local control commenced. However, complete control over the settings is provided using the LCD touch panel  402  so that a user can override the control settings. For example a user can vary the settings for a specific FFU, groups of FFUs or the entire clean room (local setting step  512 ). The signal provided to the FFU network  306  will include an address for the FFU or FFU group and the desired setting for that address. When the server  310  is again connected, or local control cancelled, a synchronised copy of the control settings from the interface memory  404  is periodically stored in the server  310  (backwards synchronisation step  514 ). Therefore, in case of an interface hardware failure or a server hardware failure, the settings (either from the server  310  or the interface  308 ) will be backed-up in the other location and will not be lost. 
         [0041]    The LCD touch panel  402  may be located at any location in the clean room, and may be connected to the interface  308  via a wired or wireless connection. It allows easy adjustment of the operating point within the clean room. This eliminates the need to change the operating point at the control room and then separately verify the changes in the clean room. This may be useful during construction of the clean room when part of the clean room may be undergoing testing and commission and the control room is not ready, in the event of a regionalized problem, or otherwise as required or desired. 
         [0042]      FIG. 6  shows another exemplary embodiment where the control panels  616  are used to control other functions within the clean room, or even throughout the building. The operating system is as described above for each of the other functions. The other functions include, but are not limited to: air showers  618 , building management system  620 , lighting system  622 , alarm system  624 , security system  626 , temperature control system  628 , air flow control system  630 , and any other desired or required system  632 . These may be arranged in groups, or individually. This may be in addition to or in place of the control of the FFUs  204 ,  304  described above. In this case the user settings are for one or more of: the fan filter units  204 / 304 , air shower system  618 , building management system  620 , lighting system  622 , alarm system  624 , security system  626 , temperature control system  628 , air flow control system  630 , and any other desired or required system  632 . 
         [0043]    For example, the control panel  616  may also be used to control an air shower system  618 . The air shower system  618  serves as a control gateway to the cleanliness to a clean room. It serves to remove particles from people and material entering the clean room. In a large clean room, where there may be a relatively large number of air showers  618  such as, for example, between  10  and  20  air showers  618 , the proper operation and control of air showers  618  is of importance in the overall clean room operation. For example, the duration of air blowing in an air shower  618  may need to be adjusted according to the clean room cleanliness conditions. The relevant setting may be adjusted by use of a computer server or the control panels  616 , with the adjustment made depending on the result of the particle count sensor. Different air showers  618  can be programmed to operate differently depending on the usage pattern of the air showers  618 . 
         [0044]    The control panels  616  may provide sufficient flexibility, and safety net, for the overall control and monitoring of the air shower system  618 , with the operation being as described above. 
         [0045]    The control panels  616  may also be used to also control building management systems  620  such as, for example, lighting  622 , alarms  624  (including particle count and climate control alarms), and security systems  626 . Building services such as lighting  622 , alarm  624  and security systems  626  are often controlled as part of the building management system  620 . This provides an efficient and effective way to manage such services. By using the control panels  616  it is possible to provide a flexible system for the overall control and monitoring of the various components under the building management system (“BMS”)  620 . 
         [0046]    By using the control panels  616 , it is possible to resolve the problem of each component  622 ,  624 ,  626  operating under a different communication protocol. This can be done by utilizing the protocol converter feature as described above. 
         [0047]    In the event of a failure of the BMS  620 , the operation of the various services can still be controlled in the manner described above. As such, and upon restoration of the BMS  620 , all changes can be automatically updated to the system. 
         [0048]    The control panels  616  may also be connected to and control the temperature  628  and air flow monitoring and/or control system  630 . Temperature and air flow are some of the most crucial factors in a clean room system as the products being manufacture in a clean room are generally sensitive to temperature change. Any products produced outside the allowable temperature range may be rendered useless, or may have to be scrapped. By using the control panels  616  to control the temperature control system  628  and air flow system  630 , in the event of a malfunction of the control server, the control panels  616  can assume the function of monitoring temperature and air flow in the clean room and allow manual or automatic adjustment to achieve the required parameters. Updates would happen as described above. 
         [0049]    Whilst there has been described in the foregoing description preferred embodiments of the present invention, it will be understood by those skilled in the technology concerned that many variations in details of design, construction and/or operation may be made without departing from the present invention.