WO 2005/052607 PCT/NZ2004/000301 MONITORING METHOD AND SYSTEM TECHNICAL FIELD This invention relates to an improved monitoring method and system for equipment or tools. Preferably the present invention may be used to monitor 5 the performance or operation of an electric fence energiser and preferably to store data or information regarding the performance of such an energiser. However, those skilled in the art should appreciate that other applications for the monitoring method and system provided are also considered and reference to use with electric fence energisers only throughout this specification should in no 10 way be seen as limiting. BACKGROUND ART In many different situations or applications, it is preferable to monitor the performance of equipment or tools. For example, in the case of electric fence energisers, it is possible to investigate a number of operational parameters of 15 an energiser to determine if the energiser has been correctly configured and is operating correctly. However, such investigations generally allow only for the real time or concurrent investigation of the energiser's performance through housing based display components linked to sensors internal to the energiser. Consequently, it is currently difficult to determine what the performance of an 20 energiser has been historically. This can cause difficulties in determining the cause of an intermittent fault present in an energiser. A service person may not be able to reproduce such faults in a workshop, nor be present in the normal operational location of an WO 2005/052607 PCT/NZ2004/000301 energiser when such intermittent faults occur. Furthermore, in some instances it is also difficult to determine the cause of a failure in an energiser after the energiser has ceased to function. Historical performance information regarding how the energiser was used can be 5 employed to determine a manufacturer's liability under warranty provisions, or to detect design faults present in the construction of such an energiser. Furthermore, such historical information may indicate how an energiser was originally configured and used, potentially highlighting problems in instruction manuals, or in the training of service personnel. 10 In a number of applications the failure of an electric fence energiser and therefore an associated electric fence can cause significant problems. For example, in the case of security fence installations, the failure of an energiser can leave a sensitive site open to unauthorised personnel. In the case of agricultural applications, large capacity energisers may be used to power 15 comparatively long fence lines or a relatively large number of fence lines. The failure of such energisers can pose significant economic risks with respect to the loss of stock or productivity of the operation in question. It is therefore preferable to have an electric fence energiser which can have a reliable and consistent performance. Furthermore, an energiser where potential failures 20 may be forecasted early would also be of advantage. An improved monitoring or data recording system and method which addressed any or all of the above limitations would be of advantage. In particular, a monitoring method or system which allowed for the recording of energiser performance or operational parameters over extended time periods, and 25 preferably which also detected and maintained a record of specific events or 2 WO 2005/052607 PCT/NZ2004/000301 operational conditions which occur during the lifetime of an energiser would be of advantage. All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that 5 any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form 10 part of the common general knowledge in the art, in New Zealand or in any other country. It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term 'comprise' shall have an 15 inclusive meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process. 20 It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice. Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only. 3 DISCLOSURE OF INVENTION According to one aspect of the present invention there is provided a monitoring system adapted to monitor the operation of an electric fence energiser, said monitoring system including, 5 at least one input line configured to receive at least one performance data signal from an electric fence energiser, wherein at least one of the performance data signals or signals are obtained from sensors monitoring internal components of the electric fence energiser, and at least one buffer data store configured to store a number of performance data readings obtained from said received performance data signal or signals wherein the buffer is continually 10 updated with new performance data readings to provide an historical performance record of the ongoing operation of the electric fence energiser, and at least one output line linked to said at least one buffer data store, said at least one output line being adapted to provide access to said stored performance data readings. 15 According to a further aspect of the present invention there is provided a monitoring system substantially as described above which also includes, at least one cumulative data store adapted to store a plurality of event indicators, wherein an event indicator is stored when an operational event is detected using said at least one received performance data signal. 20 The present invention is adapted to provide a monitoring system and associated method of using or operating same. Preferably, the monitoring system and its associated method of use may be employed to monitor the performance or operation of any number of different types of tools, plant or equipment. The present invention may be employed preferably in a data recording or capture 4 WO 2005/052607 PCT/NZ2004/000301 role to provide a record of the performance of the equipment in question over a set or known period of time. Preferably the monitoring system provided may be used in conjunction with an electric fence energiser, or a plurality of electric fence energisers. Electric fence 5 energisers operate over long periods of time and in a number of instances, it is preferable to monitor and also record historical performance information in relation to an energiser. Preferably the present invention may provide a record or indication of energiser performance extending back a known period of time, where such historical information may be of use to diagnose intermittent faults in 10 the energiser for example, or alternatively to provide a record of how an energiser was used, configured or installed. Alternatively, or in combination with the above, the present invention may also provide a performance data recording mechanism. Reference throughout this specification will also be made to the present 15 invention being used to monitor the performance or operation of a single electric fence energiser only. However, those skilled in the art should appreciate that other applications are also envisioned where the present invention may monitor the performance of two or more energisers or alternatively may monitor alternative types of equipment, tools or plant. Reference to fence energisers 20 only throughout this specification should in no way be seen as limiting. In a preferred embodiment the present invention may include at least one input line which is adapted to receive or carry at least one performance data signal supplied from an energiser. An input line may extend from at least one sensor or transducer used to generate such performance data signals, or alternatively 25 may extend from a simple connection to a current carrying line of the energiser. 5 WO 2005/052607 PCT/NZ2004/000301 Those skilled in the art should appreciate that such input lines may run only in the interior of an energiser housing, or alternatively they may extend out from the housing to a remote external monitoring system if required. In a preferred embodiment a performance data signal may be generated for 5 each operational parameter or attribute of interest with respect to the performance of an electric fence energiser. In a further preferred embodiment a single performance data signal may be carried on a single input line. In such an embodiment a single data signal may provide information with respect to a single operational parameter or attribute of 10 an energiser where this information in turn is carried by a single input line. However, in alternative embodiments a plurality of performance data signals may be multiplexed onto and carried by a single input line if required. Furthermore, in other instances, a single performance data signal may provide information with respect to two or more operational characteristics or attributes 15 of an energiser if required. In a preferred embodiment components or electrical systems used to provide the physical components of the monitoring system may be located or assembled within the interior of an electric fence energiser housing. The input line provided can run within the interior of an energiser housing directly from sensors, or 20 connections to currents carrying conductors to components of the monitoring system. In this way the monitoring system may be located within the monitored electric fence energisers housing. However, those skilled in the art should appreciate that other implementations of the present invention are also envisioned. For example, in one alternative 6 WO 2005/052607 PCT/NZ2004/000301 embodiment the physical components used to provide such a monitoring system may be located remote from and external to the energiser but linked to the energiser through the plurality of input lines provided. Furthermore, in some instances, a limited number of input lines may also have the performance data 5 signals employed multiplex onto same for transmission to the monitoring system. Those skilled in the art should appreciate that reference to the provision of the monitoring system within the interior of electric fence energisers should in no way be seen as limiting. In a preferred embodiment the monitoring system may include at least one 10 buffer data store configured to store a number of performance data readings obtained from a performance data signal or signals. Preferably a buffer data store may maintain at least a temporary record of such performance data readings for a known or set period of time. In a preferred embodiment a performance data reading may be formed from a 15 digitised sample of a performance data signal. Digitised data readings may be readily stored or recorded using well known digital electronic components which are available at relatively low cost. Furthermore, a digitised sampling scheme reduces the amount of data which needs to be stored to provide a historical record of energiser performance. 20 Reference throughout this specification will also be made to a performance data reading being a digitised sample of an analogue performance data signal. However, those skilled in the art should appreciate that performance data signals may in turn be digitised, with signals being composed from a number of digital performance data readings originally obtained from a signal sampled 25 within an electric fence energiser. Those skilled in the art should appreciate that 7 WO 2005/052607 PCT/NZ2004/000301 reference to the above only throughout this specification should in no way be seen as limiting. In a preferred embodiment the operational parameters monitored or of interest to the monitoring system provided may include but need not be considered to be 5 limited to; * Energiser Pulse Fire Rate 0 Energiser Output Voltage * Energiser Output Current 0 Energiser Return Voltage 10 0 Energiser Return Current * Storage Capacity Charge Level * Earth Voltage * Energiser Mains Power Supply Voltage 0 Energiser Battery Voltage 15 o Energiser Internal / External Housing Temperature Readings In a preferred embodiment a single buffer data store may be provided for the monitoring system. A single buffer data store may store at a single end location one or more individual performance data records which can be sourced from one or more performance data signals. 20 Reference throughout this specification will also be made to the monitoring system including a single buffer data store only to store a plurality of individual performance data readings. However, those skilled in the art should appreciate that plurality of buffer data stores may also be provided, with a single address in each data store storing a single performance data record if required. Those 8 WO 2005/052607 PCT/NZ2004/000301 skilled in the art should appreciate that reference to the use of a single buffer data store throughout this specification should in no way be seen as limiting. Preferably a buffer data store may be adapted to store a relatively large number of data readings over an extended period of time, thereby providing a historical 5 record of energiser performance over the time period involved. In a further preferred embodiment the data readings involved may only be temporarily stored within the buffer data store. Comparatively old data readings may be overwritten by newer incoming data readings, thereby creating a monitoring record which extends back over a known or set period of time only. 10 In a further preferred embodiment a circular addressed data buffer may be employed as a buffer data store in conjunction with the present invention. A circular addressing scheme may be used for memory locations within the buffer data store into which data readings are stored. The circular addressing scheme employed may continuously loop over itself to overwrite old data with newer 15 incoming data as time progresses. Reference throughout this specification will also be made to a buffer data store being implemented through a circular data buffer. However, those skilled in the art should appreciate that many other different types of digital storage components, systems or techniques may also be employed in conjunction with 20 the present invention and reference to the above only throughout this specification should in no way be seen as limiting. In a preferred embodiment the monitoring system may also include at least one cumulative data store. A cumulative data store can be adapted to store a plurality of event indicators, where event indicators are in turn generated 9 WO 2005/052607 PCT/NZ2004/000301 through the detection of a particular operational event experienced by an energiser. Such operational events may be detected from the information present within a performance data signal or signals, and on detection of such events, the monitoring system can generate and subsequently store an event 5 indicator within a cumulative data store. In a preferred embodiment a cumulative data store may record or store event indicators generated over the working life of an energiser. In such embodiments, the cumulative data store may provide a permanent record of operational events which the energiser has experienced, where this information 10 is preferably stored permanently in conjunction with the monitoring system provided. Reference throughout this specification will also be made to event indicators being stored permanently within a cumulative data store where these event indicators are generated and stored over the normal operational lifespan of an 15 energiser. However, those skilled in the art should appreciate that the time period over which event indicators are stored may be reduced in other instances or alternatively the cumulative data store may be reset or emptied if required. Preferably the operational events detected from performance data signals may include but should not be considered to be limited to; 20 e Energiser tick - Measure of the service life of the energiser - number of pulses missed - period of time pulses missed e Output over voltage - indicates critical overvoltage condition 25 * Output Voltage - monitoring 'standard' voltage produced 10 WO 2005/052607 PCT/NZ2004/000301 e Output under voltage - indicates fence overloads " Fence return under voltage - indicates fence integrity compromised " Output current flow - monitors output current produced * Earth over voltage - indicates poor fence/earth loop 5 resistance * Stored energy upper limit - indicates fence approaching overload condition e Mains power brownout - indicates power supply problems " Mains power fail - indicates power supply problems 10 0 Battery power fail - indicates power supply problems * Over temperature - indicates internal heat dissipation problems e External temperature - minimum and/or maximum threshold indicator 15 - record on detection of another event - provides thermal profile record over time " Fast fire - indicates a critical fault condition e Internal software errors - indicate memory errors, trap conditions, overflows, bounds errors etc. 20 In a preferred embodiment the present invention may include a cumulative data store for each event which is to be detected and/or monitored. A cumulative data store may record a numerical value indicative of the number of times which a particular operational event has been detected. The generation of an operational event indicator will in turn increment the count or counter provided 25 by such a cumulative data store. Reference throughout this specification will also be made to a cumulative data store being provided for each and every event to be monitored in conjunction 11 WO 2005/052607 PCT/NZ2004/000301 with the present invention. However, those skilled in the art should appreciate that various other types of memory or data store technology may also be employed to implement the present invention and reference to the use of such simple counters only throughout this specification as cumulative data stores 5 should in no way be seen as limiting. In a preferred embodiment the timing or rate at which data is recorded or stored in either or both a buffer and cumulative data store may be in turn controlled by the rate at which the electric fence energiser pulses or 'ticks'. Energiser ticks (indicative of the energiser placing an electrical pulse on a fence line) are 10 relatively regular and may be used to approximate a time measurement clock. Energiser ticks may in turn be used to control the speed or rate of operation of the monitoring system as energiser ticks in turn indicate the speed of operation of the energiser to be monitored. The energiser may in practice function as a real time clock facility for the monitoring system where each energiser tick 15 triggers the clocking of the next step or stage of operation of the monitoring system. Those skilled in the art should appreciate that reference to historical data records and records maintained over set or known periods of time may be measured or approximated through a specific number of energiser ticks or 20 pulses. Although energiser ticks cannot be relied on for high accuracy, they will provide an effective clock system for the monitoring system provided and can in turn be used to provide an approximate indication of actual elapsed times depending on the firing rate of the energiser involved. However, it should also be appreciated that a relatively accurate real time clock system may also be 25 employed to also allow the recording of actual real time values in conjunction 12 WO 2005/052607 PCT/NZ2004/000301 with the performance monitoring facilities of the present invention if required. In a preferred embodiment the monitoring system may include at least one output line linked to any or all of the data store or stores provided. An output line may provide access to stored performance data readings in conjunction with 5 a buffer data store, or alternatively access to a count of the number of event indicators stored with respect to a cumulative data store. In a further preferred embodiment an output line may be provided for each data store employed in conjunction with the present invention. However, in alternative embodiments, output signals or data from a number of data stores 10 may be multiplexed onto a single or relatively small number of output lines if required. Preferably an output line may be linked to an indicator or display system which can provide a visual display to a user of the data stored and recorded. Alternatively, an output line or lines may in turn be linked to further 15 programmable logic components, such as a computer system, for further processing or interpretation by such a computer system if required. The present invention may provide many potential advantages over the existing prior art. The present invention may be adapted to provide a historical record of a piece 20 of equipment, tool or preferably an electric fence energiser's performance over an extended period of time. Performance data readings indicative of particular operational parameters of the equipment or energiser involved may be provided extending back prior to the current time for more information regarding how the equipment has been operated or performing. 13 WO 2005/052607 PCT/NZ2004/000301 Furthermore, the present invention may also provide a cumulative data store to provide a cumulative record of specific types of events which have occurred over the lifespan of the equipment, or preferably energiser involved. Such cumulative data stores may provide an indication as to how equipment has 5 performed over its useful lifespan and also the conditions under which such equipment has been used. BRIEF DESCRIPTION OF DRAWINGS Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the 10 accompanying drawings in which: Figure 1 shows a block schematic diagram of components employed and signal data lines provided in conjunction with a monitoring system provided in accordance with a preferred embodiment, and Figure 2 shows a flow chart of a software process executed by the event 15 processor discussed with respect to figure 1. BEST MODES FOR CARRYING OUT THE INVENTION Figure 1 shows a block schematic diagram of components employed and signal data lines provided in conjunction with a monitoring system (1) formed in accordance with a preferred embodiment. 20 The monitoring system (1) includes a number of input lines (2), a buffer data store in the form of a circular data buffer (3) and a number of cumulative data stores in the form of event counters (4). A series of input lines (2) are linked to a number of input comparators (5) which in turn feed their outputs into a 14 WO 2005/052607 PCT/NZ2004/000301 microprocessor (6). The input lines (2) are linked via a series of interface stages (7) through to an electric fence energiser (8). Transducers or sensors within the energiser provide a source for performance data signals which in turn are transmitted 5 through to the input lines (2). A series of electrical comparators (5) are used to filter the signals on some of these lines (2) before the signals involved are supplied to a monitoring microprocessor (6). However, one single input line (2) is adapted to carry multiplexed, unfiltered performance data signals directly to the microprocessor 10 (6). The buffer data store formed by the circular buffer (3) is configured to receive performance data readings from the microprocessor (6). The circular buffer can receive unfiltered samples or readings made from performance data signals and store these readings in the circular re-addressed memory locations within the 15 buffer. As newer data readings are obtained, the older data stored in the addresses of the circular buffer will be overwritten. The comparators (5) are configured so as to provide either a high or low voltage signal only depending on the level of the performance data signal received. These comparators will in turn provide an interrupt or flag signal to the 20 microprocessor (6) when a performance data signal is above or below a specific threshold level. The received comparator outputs can in turn be used by the microprocessor (6) to detect specific event conditions associated with the energiser (8). On detection of an event, an event indicator subsequently generated by the 15 WO 2005/052607 PCT/NZ2004/000301 microprocessor and represented through an increment signal sent to one or more of the cumulative data store counters (4). Preferably a single event will generate a single event indicator which in turn is used to increment the count of a single cumulative event counter (4). 5 The monitoring system (1) also includes an output stage (9) which allows a user of the monitoring system to access the data or information stored within each type of data store (3,4). In the embodiment discussed this output stage may be formed from an internal or external device which may be connected to the energiser with a specific data link and subsequently connected, either directly or 10 indirectly, to a data processing unit such as a PC, or dedicated display unit. Such a unit may be a mobile or hand held unit, or maybe a full desk top appliance. These elements can provide a user interface which can allow the data stored by the monitoring system to be retrieved and displayed on demand to a user. 15 Figure 2 shows a flowchart of a software process executed by the processor (6) discussed with respect to figure 1. In the initial stage A of this process, the processor receives performance data signals via an input line. Next at stage B the processor samples these received signals to provide 20 performance data readings. At stage C the processor considers the input signals supplied by the comparators (5) to determine whether a specific energiser event has been detected. If a specific event has been detected, at stage D, the processor 16 WO 2005/052607 PCT/NZ2004/000301 generates an event indicator signal which is used to subsequently update or increment one or more cumulative event counter data stores. Lastly, at step E the event processor stores the performance data readings it obtains at stage B within the memory locations of the circular event buffer. The 5 processor then subsequently waits for a further energiser tick or pulse to trigger the same cycle of operations again. Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof. 17