Commodity dispensing apparatus.

The invention relates to commodity dispensing apparatus particularly for dispensing electricity, gas, water or the like.

Conventional commodity dispensing apparatus presently in widespread use for dispensing predetermined; quantities of, for example, public utilities such as electricity, gas, water, and district heating are essentially electro-mechanical machines. The coin-in- the slot meter is typical of these.

Recent new designs of commodity dispensing apparatus have utilised electronics, and particularly microprocessors. Inone such arrangement the operating parameters of the dispensing apparatus, that is, the rate at which the commodity is to be dispensed and the amount of credit allowed are set-up by feeding coded tokens into appropriate reading means in the apparatus. The preferred form token is a magnetically encoded card and separate cards are employed for the rate of dispensing and the credit allowance.

The present invention seeks to provide the facility whereby these parameters, at least, may be checked or periodically monitored in order to establish amongst other things that the apparatus is functioning correctly and has not been tampered with.

According to the present invention there is provided a commodity dispensing apparatus of the type having token reading means and commodity dispensing means which is operative to dispense the commodity according to the parameters determined by tokens given to the token reading means, including means for checking the operative status of the apparatus, means for storing and carrying out instructions for at least one status check step, and means responsive to a further token being given to the token reading means to cause said instructions to be carried out.

In the preferred form of the invention operation of the commodity dispensing apparatus is controlled by a microprocessor according to a stored digital program and the status check is also carried out by the microprocessor according to a further stored digital program. The result of the status check is displayed for a short period by alpha numeric display means which normally shows the cumulative total of commodity dispensed.

The invention and how it may be carried into practice will now be described, by way of example only, with reference to the accompanying drawings, in. which: <ul id="ul0001" list-style="none"><li>Fig. 1 shows a circuit diagram of the commodity dispensing control circuit of such an apparatus,</li><li>Fig. 2 shows a flow chart of a complete status check program, and</li><li>Fig. 3 shows a flow chart of commodity control during a display step.</li></ul>

In a commodity dispensing apparatus of the type being referred to, the rate at which the commodity is dispensed is set up by feeding a "master" token to the apparatus and this may determine both the dispensing tariff rate and any debt recovery deduction to be made. The commodity is then purchased by feeding a "value" token to the apparatus which sets up the credit allowance of the consumer less any deductions to be made. The apparatus then continues to dispense the commodity until the credit is used up, whereupon either the supply may be disconnected or, the apparatus can continue to operate in an emergency credit mode.

In the electricity dispensing apparatus of Fig. 1 the control circuit basically comprises means (not shown) which measures the number of units of electricity consumed, a circuit breaker means (not shown) which connects the consumers circuits to the mains supply, and which is controlled by the circuit of Fig. 1. At the heart of this control circuit is a microprocessor 1, the token reading means is illustrated schematically at reference 2 (the mechanical and electrical details of the arrangement are omitted for clarity) and is connected to an input 3 of the microprocessor 1 through an amplifier network 4. A memory device 5 is connected with the microprocessor 1 by the read and write connections 6 and 7 respectively. The output of the electricity measuring means is connected to a control circuit input 8 and provides a digital input pulse per one tenth Kwh and is connected via input processing circuits 9 and 10 to the microprocessor 1. An alpha numeric display assembly generally indicated at 11, powered by display driver circuits 12 and 13, is connected by a branched data output highway l4 to microprocessor 1, memory device 5, and address latch 15.

The display assembly 11 may also include a plurality of indicator lights, in the present example there are four which indicate respectively a fault, card error, wrong scheme, and emergency. These are: provided by light emitting diodes l6, 17, l8 and 19, energisation of which is controlled by transistor switches generally indicated at 20 controlled by an amplifier block 21 by further outputs from microprocessor 1. Also provided on the front face of the meter (not shown) is an "emergency credit" push button which when depressed breaks a light path between a further light emitting doide 22 coupled to a light sensor further controlling energisation of input to the microprocessor 1.

Further outputs from the microprocessor 1 control motor drive circuits 23, 24 which provide power to a motor 25 which propels the token reading means (not shown). In the presently described example the token comprises a magnetically encoded card and optically coupled sensors 26, 27 are positioned in the entrance and exit slots of the token reading means such that their respective light beams are broken by the card in its passage through the token reading means. Outputs from the sensors 26 and 27 are connected back to the microprocessor 1 which provides control signals to motor drive circuits 23, 24 as required.

A memory device incorporated in microprocessor 1 provides permanent storage for the operating programs for microprocessor 1 for all facets of its operation and memory device 5 provides a temporary storage capacity for such quantities as value of commodity dispensed, credit allowance, credit remaining, commodity dispensation rate, and numbers of token cards presented. The memory device 5 is powered by a battery 28 in the event of mains power failure in order to retain system parameters

The initial stage in operation of the apparatus is a presentation of a "master" card to the token reading means which breaks the beam of sensor 26, the microprocessor 1 energises drive circuits 23, 24 to drive motor 25 which propels the card through the token reading means, and which on its exit breaks the beam of sensor 27 which results in microprocessor 1 de-energising circuits 23, 24 and motor 25. During its passage past the read head in the token reading means 2 the magnetically encoded stripe on the card generates corresponding electrical signals in the amplifying network 4 which is fed to input 3 of the microprocessor l. These signals first identify the card and then represent the parameters concerned and quantities relating thereto. In the next stage the "value" card is presented to the token reading means 2 and in the same manner this generates signals representing the value of the quantity of commodity to be dispensed. The "value" card is erased in the token reading means 2 in response to a signal from microprocessor 1 in order to prevent subsequent reuse of the card. The apparatus thus set up now commences operation by closing the supply circuit breaker (not shown) until credit is exhausted. A conventional electro-mechanical electricity meter displays a running total of electricity consumed by means of the positions of rotating dials or pointers, in a similar way the present apparatus maintains a visual display of the credit value by means of the digits of display assembly ll.

According to the present invention a check may be made on the operative status of the apparatus by presenting a third, generally referred to as an "engineers", card which brings into operating a special sequence of checks, instructions for which are stored in a check or test program held in the memory device of microprocessor 1. Upon being presented to the token reading means 2 the signals -encoded on the card identify it to the microprocessor 1 as an engineers card, which immediately results in the microprocessor calling up the appropriate engineers card program.

The flow chart of Fig. 2 shows the functions of this program, which are normally executed, in parallel with continuing normal operation, i._e. commodity dispensing, of the apparatus. Referring now to the flow chart of Fig. 2 the first step 30 represents program call-up, in the next step 31 the motor 25 is again energised to return the "engineers" card to the engineer. Normally, value token cards are retained by the machine in an internal bin, preferably also the magnetic encoding is erased by passage through a second stage of the token reading means 2.

The check program proper begins at the next step 32 in which all elements of the display assembly 11 are simultaneously energised. At this and each subsequent check stage a five second display sub-routine 33 (see also Fig. 3) is called into operation in order to maintain the display for a predetermined period of five seconds sufficient for, say, a hand written record to be made.

At the end of the five second period the program automatically steps onto the next stage for example, by adding a one to a sub-routine counter which, when it reaches a total corresponding to the number of sub-routines in the engineers test program returns the apparatus to normal display mode. Any number and type of check or test sub-routines may be incorporated in the program as required and those shown in Fig. 2 are given only by way of example.

The following sub-routines are shown in Fig. 2, at 34 a check of the state of emergency credit switch 22, at 35 a display of the number of value cards presented to the apparatus, which number is retained in an internal register of memory device 5, at 36 a similar display of the total quantity of cards presented followed by an optional sub-routine 37 in response to depression of a reset switch by which the quantity of cards and value of cards registers may be cleared. The next stage 38 is a display of the total number of cards accepted which is normally not , re-settable and is a cumulative total of the number of cards presented to the machine during its lifetime. The next following five display steps 39, 40, 41, 42 and 43 display the various tariff rates according to which the machine is operating, and enable the engineer to check the machine is operating as intended, is not faulty, and has not been tampered with. The final display of this example is of the amount of emergency credit, if any, which the machine has been authorised to allow.

As previously mentioned, the engineers check program is carried out in parallel with normal operation of the commodity dispensing apparatus and only the display functions are interrupted temporarily. In order to permit this a program represented by the flow chart of Fig. 3 is brought into operation which the microprocessor 1 continually cycles and monitors first if any commodity is being used, which is presented by the decision block 45. If the result is positive then the microprocessor 1 updates the commodity register in memory device 5 by the appropriate amount in step 46. Subsequently, if commodity is used at step 47 a further decision is made concerning whether or not all commodity is used, i.e. whether the is remaining credit. If credit is exhausted an output is provided to the circuit breaker means to disconnect the consumers circuits from the commodity supply. This sub-routine continues cycling until the check program is completed whereupon the microprocessor 1 returns to operating according to its normal operating program.