WO1994009388A1

WO1994009388A1 - A program unit of the prom-type and a marker with such a unit

Info

Publication number: WO1994009388A1
Application number: PCT/DK1993/000336
Authority: WO
Inventors: Willy Palle Pedersen
Original assignee: Willy Palle Pedersen
Priority date: 1992-10-14
Filing date: 1993-10-14
Publication date: 1994-04-28
Also published as: DK125692D0; AU5175493A

Abstract

A program unit (PPD) of the PROM-type, particularly a unit with low program capacity, consists of a plate with pre-prepared conductor paths (16) between a common terminal (12, 14) and a row of program terminals (18), the conductor paths being made non-conductive by selective destruction. An associated programming apparatus has a socket (24) for receiving the PPD unit and a display (26) for displaying a code read into the apparatus, and it includes means for sequentially burning off the conductor paths relevant for that code. The program units are totally passive units, which are suitable for mounting e.g. in electromagnetical markers (2).

Description

A program unit of the PROM-type and a marker with such a unit.

The present invention relates to a method of producing a program unit of the PROM type. The invention, although having a broader scope, is related to electromagnetical markers, which, e.g. from a subterranean position, may transmit a signal that is usable for a refinding of the marker position by means of a search detector, the signal being modulated by a binary pulse signal that can be detected for identification of the marker. By way of example, it may be desirable that the marker can reveal itself by a two digit figure between 00 and 99, when there is an established codex for the meaning of these figures.Thus, markers used for marking of telecom cables may be programmed with figures between 30 and 39, all according to the kind of the marked point, while for installations pertaining to electrical mains, district heating, water supply and sewage systems other respective figure groups can be used, e.g. 00-09, 10-29, 40-49 and so forth.

When such a programming is used, all the markers may be adapted to work on the same frequency, while it has otherwise been an established practice that for the different areas the markers have been used with respective different frequences, which is unsuitable for various reasons. With the use of the programmed or self- identifying markers working on the same frequency, an operator belonging to one of the said areas will also be able to detect the presence of markers belonging to other of the areas, and this may be very helpful in the practical work.

According to this example the single markers should be programmed in a fixed manner for transmitting the respective signal codes, which should by all means be constant. If, by way of example, all telecom cable splicings are marked with the marker ciffer 34, it will be imperative that this marking be maintained and not changing to any other ciffer, which might refer e.g. to a branch pipe on a water supply pipe. It is well known that for such stable program ings in electronical devices the so-called PROM units are used, which are mostly, themselves, electronic units prepared so as to be programmable as desired. What should be achieved is a serial row of contact points, through which there is access and non-access, respectively, in an ordered manner, to a conductor, this being used in the manner that by scanning along the row of contact points it is possible to detect a certain serial combination of points, in which there is connection and non- connection , respectively, which as well known is the basis for the determination of figures and characters in the binary system of notation.

PROM s with extremely high capacity have been developed for use in the data technology, but for the example here considered it is sufficient with a very modest capacity, as already the use of seven contact points will be sufficient to cover the entire two-digit range. Thus, a very small PROM could be used, but the associated programming equipment is very expensive, and beside, for the said example there is the special circumstance that in a passive marker, which is energy supplied by means of a field transmitted from the search detector, there will only be a very small amount of energy at disposal, and the usual PROMs require a certain supply of energy to be operative. Normally, this is no problem when a usual current supply can be used, but in the present connection the problem is decisive, because the search detectors should be unrealistically powerful in order to supply energy also for actuatig the PROM. Even in battery driven, active markers this problem will be noticeable, because the current consumption of the PROM will reduce the lifetime of the active marker to one fourth or less.

Usual electronic PROM units comprise a large number of pairs of transistors, which, by the programming, can be affected to be permanently conducting or non¬ conducting. When it is sufficient to make use of relatively few contact points it is practically possible to to use a more simple, passive system, based on the establishing of a physical conductor connection between the common lead and the terminals representing connection , while the terminals representing non- connection are left without such connections. In practice this is easy to arrange in such a manner that it is sufficient to effect a selective soldering of short wires between the relevant terminals and the common lead; this can be done in a relatively inexpensive manner, and it is achieved that this PROM will be totally passive, i.e. be operative without any energy consumption at all. Thus, this solution will be fully usable in or for the specified example.

However, there will be an associated problem in that the manufacturing or stock keeping enterprise may have difficulties in administering the storage of the many numbers of goods constituted by the uniform markers with different identification numbers. Ideally, the stock keeping marker supplier should have at disposal unprogrammed markers, which in a simple manner could be programmed according to actual orders, without interception in the very manufacturing of the markers, but it has been found difficult to accomplish this in practice.

The invention provides for an acceptable compromise, whereby the markers can be produced as standard units missing only a single component, viz. the PROM unit, which may be available as a standard unit that is programmable in a simple and rapid manner in the stock keeping enterprise and - still in that enterprise - be finally mounted in each single marker unit, without this unit having to be returned to the manufacturing enterprise for the final completion thereof.

In practice the manufactured markers are left with an outer cavity, in which there is provided a socket part for receiving an individually programmed PROM unit, after the insertion of which the cavity may then be cast out with a hardening casting mass rendering the marker sealed towards the surroundings. Suitably this may be done by moulding out the cavity with a thermoplastic material supplied e.g. from a glue pistol delivering a hot thermoplastic material.

As mentioned, the associated PROM unit can be made by selective soldering of connections between the common lead and the selected terminals, but the invention provides for an almost opposite solution, namely by prearranging connections between the common lead and all of the terminals, whereafter, based on these standard units, it is possible to prepare the single units for their intended use by destroying the connections which should not be active. Such a selective destruction can be much easier than a corresponding selective mounting of the connections, i.e. the adaptation of the units can be effected under non-factory conditions. The factory production of the units will also be easy, preferably by a production of simple print plates on which all the connections are present.

Thin print leads are easy to remove or destroy in a simple manner, viz. based on a selective physical burning off by means of a strong current impulse, whereby the conductor metal melts or evaporizes at the thinnest stretch of the lead. In order to make this extra easy to carry out under non-laboratory conditions the invention also provides for an apparatus unit that can do the job just by a reading-in of the desired figure. This will be further discussed below.

At the stock holding place a sufficient number of fully uniform markers can be at disposal, and the markers may be programmed according to received orders. Optionally, the program unit, named PPD (passive program device) , may be placed cast into the marker already in the marker manufacturing enterprise, but with a flat cable connection to a likewise cast-in, yet externally accessible connector socket, which may then be connected with the programming apparatus unit mentioned above, inasfar as this unit may well serve its purpose even if the PPD is moulded-in in the marker. However, in markers to be placed in the ground the existence of exposed socket parts may be undesirable, so preferably the stock holding enterprise will execute both the programming and a final casting-out of the markers. Given this option, the final casting-out may be effected with differently coloured, user related materials, e.g. such that a red casting out will refer to the district heating area.

An alternative possibility will be to keep on stock preprogrammed PPD s, such that for the delivery of the markers it is sufficient to find the correct PPD and mount it in the socket of the marker and then effect the final casting-out.

It is furthermore possible to cast-in the PPD totally, i.e. so as to exclude any galvanic connection with the surroundings, but with an associated control unit for a sequential or stepwise coupling in of the leads in order to achieve a selective burning of these by means of energy pulses transferred in a wireless manner, primarily by an inductive coupling. Only care should be taken, then, for a good screening-off of the remaining electronics, to avoid damaging thereof. Optionally, however, the required energy can be delivered from a built-in battery for just this purpose, such that it is sufficient to supply low energy control pulses from the outside.

In the following the invention is described in more detail with reference to the drawing, in which:-

Fig. 1 is a perspective exploded view of a marker according to the invention,

Fig. 2 is a plan view of a PPD used therein,

Fig. 3 is a perspective view of an apparatus for programming the PPD, and

Fig. 4 is a perspective view of a socket portion in the marker.

In Fig. 1 is shown a stabmarker member comprising a housing 2, in which there is mounted a ferrite rod having wound upon it a coil 4 which, in a manner not shown, is connected with a condenser for forming an oscillating circuit having a standardized resonance frequency. In the interior of the marker there is also mounted an electronic unit for scanning a program unit 8 in order to modulate the ringing signal from the marker when the oscillating circuit is actuated by means of a search detector. The program unit 8 is mounted in a socket 10, whereafter the remaining opening in the marker housing is closed by casting it out with a suitable moulding mass, e.g. a thermoplastics from a glue gun.

The program unit 8 in the form of the said PPD is made as a print, Fig. 2, having two broad outer leads 12 and 14 and narrow leads 16 extending inwardly therefrom to respective individual terminals 18. It will be understood that in selectively breaking the leads 16 it is possible to program the unit corresponding to one of the binary figures located within the capacity of the unit, given by the number of these leads.

For the burning of the required leads 16 the apparatus shown in Fig. 3 can be used, this apparatus having a socket 24 for receiving the terminal legs of the unit, i.e. terminal legs 18 of the leads 16 and terminal legs 20 and 22 of the common leads 12 and 14. The terminals 18 occur in pairs, but for each pair there should be only one active terminal, such that there is a total of seven terminals with connections to both of the common leads 12 and 14. A terminal then being "0" or "1" will depend of whether its connection to the operative common lead, e.g. lead 12, is non-intact or intact, respectively, and in order to increase the operational safety it is preferred to make use of the opposite condition of the connection to the other common lead, 14. Thus, for each pair of terminals 18, one of the narrow leads 16 should be broken.

The said programming apparatus has a display 26 which, by means of a suitable read-in device, can be brought to show the figure to be coded into the PPD, and a built-in translator is thereby prepared for controlling the apparatus in accordance with the code of the particular binary figure. A built-in heavy current generator, e.g. just a battery charged condenser, is then started for enabling the selected leads 16 to be burnt off by a stepwise switching between the respective terminals 20 and 22 and the associated terminals 18, the heavy current being supplied only to the relevant connections. Thereafter the PPD 8 is ready for insertion into the socket 10 in the marker 2.

As mentioned, the single pairs of terminals should be mutually connected, but this is achievable in a simple manner in that the corresponding socket terminals 28, Fig. 4, are connected mutually before the mounting and casting-in of the socket 10 in the marker; in Fig. 1, the top side of the factory made casting-out is shown at 30.

It could be possible to use a PPD with only a single row of terminal legs 18, but this would cause problems by the selective burning off of the leads 16, as so-called back-paths in the form of parallel current paths would then cause troubles. By the temporary separation of the terminals in two separate rows, each with connection solely to one or the other of the common lead 12 or 14, the burning-offs can be effected without any kind of back path problems. It„ should be mentioned, however, that the lead breakings can be effected by scraping or by laser irradiation, whereby a single terminal row could be sufficient.

In the present context the invention is described in connection with the discussed markers, but it will be clear to every expert that the invention shows towards further perspectives also in connection with units of microscopic pithes, which, however, should not be discussed further at this place.

In the macroscopical area it will be an alternative possibility to make use of a row of small switch-over units, called DIP-switches, which are operable to connect a central contact point with either one or the other of two opposed contact points, whereby the operator, for implementing a certain programming, should only be confident with the binary codes or have at disposal an easily understandable table of these relative the associated decimal figures.

In practice it will be preferred to work out the PPD as a print card, which may be produced in large numbers on a base plate, from which the single units are cut out. Instead of the legs on the unit shown it is possible to provide edge terminals to be contacted by an insertion of the card into a counterpart socket.

Claims

C L A I M S :

1. A program unit of the PROM type, particularly a unit of low program capacity, consisting of a plate with pre-manufactured conductor leads between a common terminal and a row of program terminals, said conductor leads being adapted to be made non-conductive by selective destruction.

2. A unit according to claim 1, adapted for selective lead destruction by application of current between the common leads and the program terminals, in which the common lead is divided into two mutually insulated leads, each connected with respective pairs of program terminals.

3. An apparatus for programming a unit according to claim 1, having means for electrical connection with the terminals of the unit and selection means for selectively showing the code to be programmed into the unit, and having a control unit for sequential, automatic current supply to the terminals, between which the leads are to be broken for achieving the displayed programming.

4. A marker having a programming unit (PPD) according to claim l, in which the PPD-unit is insertable into a socket provided in a cavity of the marker, or in which a rigidly built-in PPD-unit is connected with such a socket in such a cavity, which cavity, upon the programming and the optional insertion of the PPD-unit therein, is mouldable-out with a filling mass, preferably a thermoplasic material.

5. A marker having a built-in program unit (PPD) according to claim 1 and comprising a control unit for a sequential, controlled coupling-in, respectively coupling-out, of leads in the PPD-unit to be either destructed or maintained for a desired programming , the destruction being effected by a current supply or by an external energy suplly, e.g by induction, or internally from a built-in battery, controlled by externally applied control signals.