GB2300734A - Multiple input elapsed time recording device - Google Patents

Abstract

A run time recorder 10e monitors the operating time of an electrical appliance driven by an ac power supply. The recorder is coupled to the supply voltage and determines the operating time of the appliance from a number of repetitions of the periodic wave form of the ac supply. The recorder may contain memory which is used to store data relating to the total run time of an appliance. A reading device (fig 1) may be coupled to the recorder device either by the leads (48/60) or via a non-contact coupling for the transmission and reception of signals to and from the recorder device. The recorder device is capable of monitoring a plurality of devices (fig 4) and/or of operating independently of power supply to a monitored appliance. An LED D4e can be used to act as a service indicating light. A further variation incorporates multiple inputs to allow multiple loads to be monitored. Referral to GB 9425469.5 is necessary.

Description

TIMING DEVICE AND READER DEVICE THEREFOR The present invention relates to improvements in the devices described in earlier UK Patent Application No GB9425469.5 filed on 16 December 1994 (copy included in this Patent Office file). The invention relates to a device for monitoring the operating or running time of an electrical system and to components of such timing devices and/or a reader of such run time recorder.

One aspect of the present invention seeks to improve the response of the interface between a run time monitoring device and a device for reading such a run time recorder. A further aspect of the invention seeks to provide a run time recorder capable of monitoring a plurality of devices and/or to operating independently of power supply to a monitored appliance.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIGURE 1 is a schematic circuit diagram of an interface according to the present invention between a run time recorder and a reader device; FIGURE 2 is a schematic circuit diagram of an embodiment of a run time recorder having multiple inputs according to the invention; FIGURE 3 is a schematic circuit diagram of the device shown in Figure 2; and FIGURE 4 is a schematic drawing of a further embodiment of a run time recorder having multiple inputs.

An adaptive data slicer 58' is shown in Figure 1 which is substantially similar to that shown in Figure 5 of earlier UK Application No GB9425469.5. The adaptive data slicer forms part of the electrical circuit for a reader/programmer described in the earlier application which is adapted to read and/or programme a run time recorder.

The adaptive data slicer acts at the interface between the reader/programmer and run time recorder in order to facilitate the transfer of data between the two devices. It has been found that the adaptive data slicer described in the earlier application requires about 5 seconds to settle before a read operation can be undertaken. If insufficient time is allowed for the system to settle then either nothing will be read or the data will be incorrect. This problem arises with the circuit shown in Figure 5 of the earlier application because capacitor Cla is discharged via diode Dla and resistor R2a and R3a when there is no run time recorder present. However, when a run time recorder is connected capacitor Cla charges via resistor R5a with a typical time constant of 4.7 seconds for the value of components indicated in the earlier circuit diagram and specification.Naturally, it would be possible to vary the time constant by altering the value of the various components, however, the circuit shown in Figure 1 also reduces this start up delay problem.

In the circuit shown in Figure 1 the various components which are analogous to those shown in Figure 5 of the earlier application are given substantially the same references suffixed with an apostrophe. It can be seen that the circuit is fairly similar to the earlier circuit except that input 48 to the run time recorder is connected to two new transistors Q3a' and Q4a' amongst other components.

When there is no run time recorder present there is no current flow through resistor R8a' (typically a 5.6 kiloOhm resistor) and hence transistor Q3a' (for example a MPSA92 device) is non-conducting. Transistor Q4a' (for example a BC558 device) is turned on by a current through resistor R10 (for example a 100 kiloOhm resistor) and accordingly point A' is pulled up to about 3 volts by resistor Rlla' (1.6 kiloOhm for example). This voltage is higher than the nominal operating voltage at point A' which is 2.4 volts. When a run time recorder is connected at points 40 and 60 the current it draws develops sufficient voltage across resistor R8a' to cause transistor Q3a' to conduct. Resistor R9a' pulls the base voltage of the transistor Q4a' above 5 volts. Transistor Q4a' is thus tumed off, releasing point A' to fall back to its normal operating voltage.The voltage across capacitor Cla' falls quickly to its normal operating voltage with a time constant determined mainly by resistor R3a' which in this example can have a value of 2.4 kiloOhm. This provides that the normal operating voltage is achieved in about 11 milliseconds. Diode D4a' prevents the reverse base-emitter voltage of transistor Q4a' from being exceeded.

Referring to Figure 2 there is shown a schematic circuit diagram for a run time recorder 10e according to the invention. Figure 2 shows a device with two inputs, the main input L provides power and allows the total connection time and number of connections of the apparatus to be monitored. The auxiliary input L1 allows the number of operations and operating time of a second load to be monitored.

Additional auxiliary inputs may be provided to allow monitoring of several other desired additional loads. RTR 10e provides an improvement over the device as described in the earlier application which has only a single voltage input used to provide power means timing and/or appliance on/off data to the RTR. In some circumstances it would be desirable to have additional voltage input, independent of the use of a monitored appliance, to allow a different operating mode of a run time recorder.

In the RTR 10e shown in Figure 2 an LED 24e acts as a service indicating light.

However, whereas the equivalent light D4 described in the earlier application only indicates when the tool or appliance is actually running and as such the user may not notice the light because they are concentrating on the use of the apparatus. LED D4e can be constantly lit when appropriate (eg a certain run time has elapsed) by using a second power input. Thus, RTR 10e has two inputs, the main input L can provide power, mains timing and control reading and writing to non-volatile memory as before, and auxiliary input L' can enable and disable the time clock and increment the event counter.

Figure 2 shows the use of the "single" line input, output and power supply line described in relation to the device shown in Figure 12 of the earlier application for example. In Figure 2 a simplified power on circuit comprising resistors Rle, R2e, R3e and transistor Qle is shown together with a single auxiliary input connected to resistors R4e and RSe and an indicator LED D4e. The power on reset circuit is a simple level detector which combined with the internal Schmitt trigger of the /MCLR input of microcomputer 1 6e (such as a PIC16LC84 device for example) releases reset at about 2.75 volts and reapplies it at 2.5 volts.In order that there is sufficient energy in the reservoir capacitor C le to allow data storage when power is removed, microcomputer 1 6e can be programmed to inhibit storage until mains has been continuously present for two seconds, say. This can guarantee that the power supply has reached its full level.

The auxiliary input L' is connected via a potential divider resistor R4e (for example 1 megaOhm) and R5e (for example 100 kiloOhm) wherein the values are chosen here to give a 5 volt input signal at minimum input voltage and to restrict the peak input current at maximum input voltage whilst having the minimum practical resistance thereby to minimise the possibility of a stray pickup activating the input. The input will also be clamped to neutral except when actually being read, so that the effects of stray capacitor coupling will be further minimised.

In use, the principal mains input L will be connected to the mains supply before the power switch, for example of an appliance or load being monitored as shown in Figure 2 or 3. Thus, the service light can operate without the apparatus running.

A further variation of a run time recorder If according to the invention is shown in Figure 4 wherein multiple auxiliary inputs, for example 1 to a desired number "N" as shown in Figure 4, allows multiple loads to be monitored. Again, the main input L can operate as for the RTR 10e or lejust described.

Claims (32)

CLAMS

1. A device for monitoring the operating time of an electrical appliance operably driven by a periodically repeating variable supply voltage, wherein the device comprises means for coupling to the supply voltage and for communicating a signal representative of the periodically repeating wave form of the supply voltage to means for monitoring said supply signal which monitoring means operably determines the operating time of the appliance from the number of repetitions of said periodic wave form.

2. A device according to claim 1 comprising a controller which operably communicates with the monitoring means and regularly stores data representative of the operating period of the appliance in a volatile memory and wherein the monitoring means detennines from the supply signal when use ofthe appliance is terminated whereupon the controller causes said data to be stored in a nonvolatile memory.

3. A device according to claim 2 wherein after commencement of a supply voltage to the appliance the controller reads said data in said non-volatile memory and stores it in volatile memory for subsequent updating during the operating period of the appliance and preferably wherein said data contains an indication of the number of times the appliance has been used and wherein said controller increments said data prior to storing said data in said non-volatile memory after termination of said supply voltage to the appliance.

4. A device according to any preceding claim wherein the monitoring means operably determines if the coupling means is coupled to an AC or DC supply and which communicates a signal indicative of said input state to a controller which is thereby able to determine a pre-selected mode of operation ofthe device.

5. A device for monitoring the operating time of electrical appliance operably driven by an input voltage wherein the device comprises means for coupling to said input voltage and communicating a signal representative of the nature of said input voltage to monitoring means which operably determines the nature of said input voltage and communicates a signal indicative thereof to a controller which is thereby able to detennine a mode of operation of the device.

6. A device according to claim 5 adapted to monitor a periodically repeating variable supply voltage to an appliance and whereupon when said monitoring means determines that such a variable supply is present at the coupling means an appropriate signal is sent to the controller which thereby operates to record the duration of the operating time of the monitored appliance.

7. A device according to claims 5 or 6 wherein when the monitoring determines that the DC supply is coupled to said coupling means it sends an appropriate signal to the controller which thereby enters an operating mode to read or transfer signals from or to a remote device.

8. A device according to any preceding claim wherein when said monitoring means determines that the periodically repeating supply voltage is no longer present an appropriate signal is sent to a controller which thereby causes data to be stored in a non-volatile memory.

9. A device for monitoring the operating time of an electrical appliance operably driven by a periodically repeating variable supply voltage, wherein the device comprises means for coupling to the supply voltage and for communicating a signal representative of the periodically repeating wave form of the supply voltage to means for monitoring said signal which monitoring means operably determines when the supply voltage is tenninated due to the absence of a repeating wave form.

10. A device according to the preceding claim wherein the monitoring means comprises an AC to DC convertor.

11 A device according to any preceding claim comprising a controller which in a non-monitoring mode, communicates with a remote device via said coupling means.

12. A device according to the preceding claim wherein during said non-monitoring mode, the device also receives an input voltage to drive its components via said coupling means and wherein said input voltage is modulated in order to communicate with said controller.

13. A device according to any preceding claim wherein said coupling means comprises means for rectifying the variable supply voltage thereby to provide a DC voltage to drive device components requiring a DC input voltage.

14. A device for monitoring the operation nin time of an electrical system operably driven by an AC supply wherein the device comprises means for coupling to the AC supply thereby to communicate a signal representative of the periodically repeating wave fonn of the supply to means for monitoring the supply which enables detennination of the removal of said AC supply in the absence of a periodically repeating wave finn.

15. A device according to claim 14 comprising a controller which detennines the run time of the monitored electrical system based on the presence of said periodically repeating wave form and wherein said memory stores data representative of said run time in a non-volatile memory after said monitoring means indicates removal of said electrical supply.

16. A device according to any of the preceding claims wherein the controller selects different addresses within the non-volatile memory to store data thereby to avoid possible corruption of data through wear-out of specific memory addresses due to repeated use thereof

17. A device for communicating with a run time recorder which comprises means to transfer power to said recorder and wherein the voltage of said output power is modulated thereby to communicate with the recorder.

18. A device according to claim 17 comprising means of identifying between signals being transmitted from the reader to the recorder and signals transmitted from the recorder to the reader.

19. A device according to claim ]8 wherein said signal detennining means effects communication of a signal received from a recorder to a contl-oller when it identifies the signal as being received from said recorder.

20. A reader device according to any of preceding claims 17 to 19 wherein certain pulse protocols are used.

21. A device for monitoring the operating time of an electrical appliance having means to output the signal compatible to be read by a reader according to any of the preceding claims 17 to 20.

22. A device for monitoring the operating time of an electrical appliance according to any of claims 1 to 18 or 21 further comprising means to enable non-tactile coupling between said device and a remote device and wherein said monitoring device and remote device can communicate with one another via a set non-tactile coupling.

23. A device according to the preceding claim wherein said non-tactile coupling means comprises antenna capable of being charged to enable capacitive coupling with said remote device.

24. A device for communicating with a run time recorder according to the preceding claims comprising a non-tactile coupling means which is preferably chargeable antenna capable of capacitive coupling with said monitoring device

25. A device having combined half duplex transmission and reception parts

26. A half-wave rectifier for a microcomputer comprising an input port of the microcomputer to which operably a alternating current is applied, said rectifier comprising diodes within the microcomputer to enable said half-way rectification

27. An electrical device for controlling the voltage applied to a microcomputer which device comprises means for delaying application of a supply voltage to power the microcomputer being applied thereto until it has reached a predetennined magnitude.

28. A device according to any of the preceding claims for monitoring the operating and/or running time of an electrical system and to components of such time devices and/or a reader of such run time recorder.

29. A device according to any of the preceding claims wherein an improvement to the response of the interface between a run time monitoring device and a device for reading such run time recorder.

30. A device according to any of the preceding claims wherein said device is capable of monitoring a plurality of electrical system and/or to operating a monitored appliance independently of power supply.

31. A device substantially as hereinbefore described with reference to or as illustrated in the accompanying drawings.

32. The use of a device as substantially herein described to monitor the operation or running time of an electrical system.