"Controlling and/or monitoring marine ancillary components"
This invention relates to marine ancillary component control and monitoring systems and methods of controlling and monitoring ancillary components provided on marine vessels.
Marine vessels, especially large ships, have a large number of ancillary components . In particular there can be a large number of windscreen wipers provided on the ship's bridge. Typically there may be up to the order of twenty wiper units each of which may have an associated heater, washer and purge system. Yet for ease of use it is desirable for the controls for all of these ancillary components to be provided at one location, for example a control panel on the ship's bridge. It will be appreciated that a large amount of wiring is required to connect all of these components to power supplies and to the control panel. In a system where the power supply is fed to the control panel and then separate power supply lines and control lines and control lines are radiated out to each of the components , the accumulation of wiring at the control panel can be extremely large and the high power/voltages required to power the ancillary components makes such a system potentially dangerous. Systems have been proposed where the power supply to each ancillary component is directly supplied thereto and separate control wires are run from a central control panel to each of the components. However, such systems still involve the use of a large amount of control cabling and each component is essentially controlled separately.
It is an object of the present invention to provide a marine ancillary component control system and methods for controlling ancillary components which alleviate at least some of the problems associated with the prior art.
According to one aspect of the present invention there is provided a marine ancillary component control system for controlling ancillary components provided on a marine vessel comprising a central control unit and a plurality of local units, the central unit and local units being interconnected by a bus and each local unit being disposed at and arranged to control a respective ancillary component in accordance with signals received from the central unit via the bus. According to another aspect of the present invention there is provided a method of controlling ancillary components provided on a marine vessel comprising the steps of interconnecting a central unit and a plurality of local units with a bus, each local unit being disposed at a respective ancillary component, and transmitting signals from the central unit via the bus to the local units to control the respective ancillary components .
According to a further aspect of the present invention there is provided a marine ancillary component monitoring system for monitoring ancillary components provided on a marine vessel comprising a central unit and a plurality of local units, the central unit and local units being interconnected by a bus and each local unit being disposed at and arranged to monitor conditions associated with a respective ancillary component and transmit signals in dependence on the monitored conditions to the central unit via
the bus.
According to yet another aspect of the present invention there is provided a method of monitoring ancillary components provided on a marine vessel comprising the steps of interconnecting a central unit and a plurality of local units with a bus, each local unit being disposed at a respective ancillary component, and transmitting signals from the local units via the bus to the central unit in dependence on conditions monitored by the local units.
Amongst other possibilities the ancillary components may comprise any one of or any combination of wipers, heaters particularly screen heaters, screen washers, actuators, pumps, and other simply controlled devices and ancillary components .
Preferably the marine ancillary component control system is a marine wiper control system for controlling wipers provided on marine vessels wherein each local unit is disposed at and arranged to control a respective wiper in accordance with signals received from the central unit via the bus .
Because each local unit has the capability to control the respective component the system makes it possible to connect the high power/high voltage supplies necessary to drive the components directly to the components themselves rather than via a remote control unit. This saves on heavy duty wiring and leads to a safer system. Further the use of a bus means that the amount of control wiring needed to install wipers and other ancillary components can be minimised since it is not necessary to route separate control wiring to each ancillary component/wiper. Preferably the bus is arranged as a ring. The
central and local units may be daisy-chained together. Where data is to be transmitted in only one direction the bus may comprise two lines. One line may be connected to an energy source and the other connected via switch means to ground. Where data is to be transmitted in two directions the bus may comprise three lines, one line being connected to an energy source, and a respective one of the other two lines being used for transmission in each direction. Opto-isolation may be provided at each point in the signal path where a signal is receivable from the bus. Preferably each local unit is connected to the bus via an opto-isolator.
The system can be arranged so that an operator may control a large number of ancillary components from one location, for example from a control panel.
The central control unit may be implemented by a computer system. Typically this will be a general purpose computer. In such a case an operator can control the ancillary components via the computer's input devices . An interface unit may be provided for connecting the central control unit to the bus.
The control system may be arranged so that the ancillary components can be grouped. This allows a selected group of components to respond to one control signal, for example a single control switch may be operated by a user to turn on a selected number or all of the wipers on a bridge ' s screens . The groupings may be permanently set during manufacture/installation or may be user configurable.
The control system may be arranged so that operation of one or more of the ancillary devices occurs automatically where predetermined conditions
are satisfied. Sensor means may be provided for outputting a signal when predetermined conditions are met. For example the sensor means may be arranged to detect rain or spray and the system arranged to automatically operate one or more wiper when rain or spray is detected. The sensor means may be connected to the bus.
One or more of the local units may comprise monitoring means for monitoring the state and/or operation of the respective component. Typically in such a case the respective local unit will comprise transmitting means for transmitting data to the central unit. This can allow service information to be collected and/or alarm conditions to be monitored. In this way, for example, the total time of operation of a wiperblade, wipermotor etc can be recorded so that a replacement/service can be made at a suitable time.
The system maybe arranged so that signals transmitted by each unit with a transmitting capability are applied directly to the bus and signals received by each unit with receiving capability are received from the bus via an opto-isolator.
The central unit may be arranged so that where a plurality of the components are to be operated simultaneously, start up of the components is automatically staggered. This serves to spread the current/power surges which occur as each component is started up. The start up of components can be arranged to be staggered individually, as groups or within groups . The time delay between the start up of each component/group can be chosen to give the desired limit in power surge. Typically the time delay will be of the order of a few milliseconds and consequently
will be imperceptible. Preferably the central unit is arranged so that it is impossible for a user to cause more than a selected number of components to start up at the same instant. In some cases a single switch may be operated by a user to start up a number of components and the start up of these components may be staggered, in other cases the user may operate a number of switches at the same time and the respective components may have their start up staggered. In some embodiments more than one central control unit may be provided. This allows the operation of some or all of the ancillary devices to be controlled from more than one location. In particular it is envisaged that local control panels could be provided in locations physically close to certain sets of components. For example a control panel could be provided for wipers in a bridge wing.
Where more than one control unit is provided, means for selecting which control unit is able to issue control signals may be provided. Such means for selecting may operate independently of the lines of the bus used for control signals.
An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which:-
Figure 1 schematically shows a marine ancillary component control system;
Figure 2 shows detail of a portion of a bus which forms part of the control system shown in Figure 1 ; and
Figure 3 schematically shows the connection of a central control unit and a local unit of the control system shown in Figure 1.
Figure 1 schematically shows a marine ancillary component control system which generally comprises a central control unit 1, a plurality of local units 2 and a plurality of sensing stations 3, all of which are interconnected via a bus 4. The bus 4 is arranged in the same manner as a ring main so that each of the local units and sensing stations 3 are daisy-chained together. This means that a connection failure or any other failure within one of the local units 2 or sensing stations 3 will not affect the functioning of the remainder of the ring.
Each of the local units 2 is disposed at, and arranged to control a respective ancillary component such as a windscreen wiper, in accordance with signals received from the central unit 1 via the bus 4. As schematically shown for some of the local units 2 in figure 1 , the high energy power supply required to drive the respective ancillary components Vpower is supplied directly to the components themselves and not via bus 4 or the central control unit 1.
In addition to the sensing stations 3, some of the local units 2 have associated sensing means 5 and/or monitoring means 6 for sensing conditions associated with the respective component and monitoring its operation respectively.
The central control unit 1 comprises a control panel (not shown) which may be used by an operator to control the operation of one or more of the ancillary components . As an alternative, as shown by the dotted lines in Figure 1, the central control unit may be implemented by a general purpose computer, which for example is disposed on the ship's bridge, and is
connected to the bus 4 via an interface 7. In such a case the operator may control the ancillary components from the computer and a separate control panel is not required. Figure 2 shows part of the control system in more detail. In particular it shows the connections between the central control unit 1 , a local unit 2 with receive only capabilities and a sensing unit 3 with transmit only capabilities . In this embodiment because the bus 4 is used to transmit signals in two directions it comprises three lines 41, 42 and 43. A first line 41 is connected to a power supply at the central control unit 1 and to supply terminals at each of the local units 2 and sensing stations 3. A second line 42 is connected to a transmit terminal at the control unit 1 and receive terminals at each of the local units 2 and sensing stations 3 having receive capabilities. A third line 43 is connected to a receive terminal at the control unit 1 and to transmit terminals at each of the local units 2 and sensing stations 3 having transmit capabilities.
In general terms the bus operates as a digital current bus so that signals are transmitted and received by respectively inducing and sensing a current flowing on respective lines 41, 42, 43 of the bus 4.
Figure 3 shows the connection between the central unit 1 and a local unit 2 having receive only capabilities in more detail. The supply terminal of the central control unit 1 is connected via the first line 41 to the supply terminal of the local unit 2 which in turn is connected through a current limiter 8 to an LED 9 and on to the receive terminal of the
local unit 2. The receive terminal of the local unit 2 is connected via the second line 42 of the bus 4 to the transmit terminal of the central control unit 1 which in turn is connected by switch means 10 to ground. The switch means 10 is controlled by a microprocessor 11.
The local unit 2 further comprises a photo- transistor 12 which is connected in series with a resistor 13 as a voltage divider, the output of the voltage divider being fed to a microprocessor 14 which in turn issues control signals to control the respective ancillary component, for example the motor of a windscreen wiper. The LED 9 and photo-transistor 12 act as an opto-isolator. This has advantages as it serves to reduce noise on the bus 4 by isolating the bus 4 from the heavy power supplies used to drive the motor etc. It also facilitates the use of different voltage power supplies for different ancillary components. Respective opto-isolators are provided at the other local units 2. The local units are disposed in close proximity with the bus 4, there being a direct connection between the bus 4 and local units 2 via the respective opto-isolators .
When it is desired to send a signal from the central control unit 1 to the local unit 2 the switch means 10 is switched under the control of the associated microprocessor 11 so that the LED 9 is connected to ground via the bus 4. Consequently a current flows through the bus 4 and the LED 9. The system is designed so that sufficient current is generated to turn on the LED 9 when the switch means is switched to ground and the current limiter 8 prevents the LED 9 from being overloaded. In practice
the LED 9 is in saturation when transmitting. As the LED 9 emits radiation this turns on the photo- transistor 12 so that the voltage level input to the microprocessor 13 is changed. In this way as the switch means 10 is switched on and off digital signals can be transmitted from the central control unit 1 to the local unit 2. The microprocessor 14 then decodes the signals to control the respective ancillary component in the desired manner. Because the system is implemented as a current bus with opto-isolation at each point where a signal is received the system is intrinsically resistant to noise. Any noise which may be picked up in the lines 41 to 43 of the bus or elsewhere will tend to cause voltage spikes which might be problematic in other implementations but which are unlikely to develop enough current to turn on the LED 9 when it is in an off state. Equally when the LED 9 is on a relatively large current is passing through the LED 9 and any noise is unlikely to be sufficient to turn the LED off. This insensitively to noise means that the bus 4 can be implemented using unshielded cable which represents a significant cost saving.
Once the system is in place it will be appreciated that it can be operated in a large number of different ways and used to provide a variety of different functions. It is envisaged that the central control unit 1 and each of the local units 2 and sensing stations 3 will have an address which may be unique to each unit or station 1 , 2 , 3 or may serve to identify a group to which that unit or station 2, 3 belongs. In this way signals may be sent from the central control unit 1 to a specific local unit 2 for
example or to a specific group of local units 2 such that the respective ancillary component or components operates in a certain manner. Thus the system could be arranged so that when an operator presses a single button on the control panel, a signal is sent to all or a selected number of wipers to commence wiping. Similarly the origin of any signal received can be determined.
Another useful feature of the control system is that it is possible to stagger the start-up of a number of different ancillary components which it is desired to operate together. For example it may be desired to switch on all of a ship's wipers at the same time, either using separate controls or a group control. However, it will be appreciated that starting a large number of motors at the same instant will cause a large "current thump" or power drain. With the present system it is possible to arrange the control signals such that when a user gives an instruction for all the wipers to start at the same moment, the actual start up times are staggered either individually or in groups by the order of a few milliseconds to smooth a. the current thump and yet cause no perceptible delay.
A further feature of the system is that adding to or reducing the number of components controlled and control units 1 included is straightforward and may be done without significant rewiring. If a local unit 2 or sensing station 3 is added or removed the bus ring
4 will still be intact and signals will still be received by the remaining units and stations 2 , 3.
Although it is not shown in detail it will be appreciated that transmission of signals in the other direction, that is to say from a local unit 2 or
sensing station 3 back to the central control unit 1, can be accomplished in substantially the same way as that explained with reference to Figure 3. For such a mode of operation a microprocessor controlled switch means is provided in the respective local unit 2 or sensing station 3 so that the third line 43 can be switched to ground. The resulting current operates an LED provided as part of an opto-isolator located at the central control unit 1 so that the signal can be detected.
The system may be arranged so that signals transmitted by each unit 1,2,3 with a transmitting capability are applied directly to the bus 4 and signals received by each unit with receiving capability 1,2,3 are received from the bus 4 via an opto-isolator.
One or more of the sensing stations 3 may be located at strategic locations to detect the presence of rain or spray and arranged to then output an appropriate signal onto the bus 4. This signal may be received and processed by. the central control unit 1 so that a signal to start operation of the desired windscreen wipers can be generated or may be acted on directly by the respective local units 2. In an alternative mode of operation, sensing means 5 specific to individual ancillary components can be connected directly to the respective local unit 2 so that, for example, when a predetermined condition is sensed, operation of the associated ancillary component occurs automatically without the signal having to pass back to the bus 4.
Where an ancillary component has an associated monitoring means 6 this can be used to monitor the
operation of the ancillary component and cause the local unit 2 to send back information to the central control unit 1 concerning the condition and/or usage of the ancillary component. This, for example, can enable decisions to be made about whether parts need to be serviced and/or replaced.
It will be appreciated that a wide range of different ancillary components can be controlled via a local unit 2 interconnected with the bus 4. Thus although this description has mainly concerned the use of the system to control windscreen wipers the system is not limited to such use. In particular screen heaters, screen washers and purge systems for purging pipes of water after washing may be controlled in addition to or instead of wipers.
The system can have various safety characteristics built into it. For example, once a wiper is operating its associated local unit 2 can be arranged to look for a refresh signal from the central control unit 1 at predetermined intervals and be arranged to revert to a fail-safe condition if say one or two of these refresh signals is missed. This, for example, would stop a wiper motor being continuously operated in the event of a malfunction or severing of the bus wires 41, 42, 43.
It will be noted that this system essentially functions as a local area network wherein processing occurs both at the central unit 1 and at the local units 2 and sensing stations 3 and therefore the system makes use of distributed processing. It is envisaged that the system would be used in circumstances where the total length of the bus 4 ring would be up to the order of 100 metres.
It is possible to implement the system with a bus 4 carrying relatively low data rates since only simple codes need be transmitted from the central control unit 1. Much of the processing necessary to control the associated ancillary components is carried out in that location.
Although in the embodiment described above the bus is implemented by physically separate wires/lines this is not essential. The bus may be configured in any way which allows signals to and/or from a number of locations to be transmitted along a common path. In particular the units may be interconnected by optical fibre cable which acts as a bus.