FR2655155A1 - Electrical device for the remote measurement of energy consumption, particularly a consumption of gas - Google Patents

Abstract

A device for the remote measurement of the index on an energy consumption meter. A gate (window) comparator (17) activates an alarm (23) when the transmission line (3) is de-energised or short-circuited, or when a reed switch (ILS2) provided for this purpose is actuated by an external perturbing magnetic field. The sensor (1), installed at the site, is bidirectional so that it is insensitive to errors in connection (6, 7 to 8, 9) at the meter.

Description

 The present invention relates to an electrical device for remote measurement of a power consumption, in particular a consumption of gas.

 It is known that, in order to avoid the displacement of operators who periodically record the indexes of consumption of gas or electricity, whether industrial or domestic, with a view to their subsequent invoicing, we are now moving towards electrical or electronic sensing systems for telereporting said indexes. The capture of the consumption index is then carried out on the site and transmitted remotely, by cable or other means of transmitting information, to a central measurement unit generally comprising counter-totalisers which are activated by the signals, in general impulse, issued by the or the capture devices.The drawback of these metreport index meter devices lies in their very purpose: because there is no longer a regular passage of operators responsible for meeting these meters on the site, the temptation is great, for some unscrupulous users, to act either on the capture device or on the transmission line, in order to distort the indications transmitted by the capture device.

Such fraud can be achieved for example
or by placing a strong permanent magnet on the insulating housing of the meter placed on the site, in order to disturb the operation of the electromagnetic pickup device that it contains;
- by short-circuiting the transmission line;
- or by making a cut of this same line.

 Note that the short circuit or the opening of the transmission line can also be accidental.

 Anyway, and especially if these incidents are not permanent, it is perfectly possible that the datalogger does not see that an anomaly has been introduced at the level of the capture device installed at one of its subscribers.

 The invention aims in particular to remedy this type of disadvantage. It also has the object on the one hand to allow easy installation, that is to say without risk of error of connecting electrical wires, an electrical pickup device in a "meter" placed on the site this installation can then be performed by a non-electrician operator, for example by a specialist in gas installations, and on the other hand to allow the measuring installation to continue to operate in the event of an anomaly (cutoff for example) of the electric power supply device of this measuring installation.

 It relates for this purpose to a device for remotely measuring a power consumption, in particular a consumption of gas, this device comprising a consumption index capture device which is integrated in the "counter" located at the consumer's site, a device for accumulating the measurement information provided by this sensing device, this accumulation device being located at a distance, and a transmission line of this measurement information from this sensing device to this accumulation device.

According to the invention, on the one hand, this sensing device comprises:
a first ILS1 electromagnetic control switch, of the "Flexible-wave switch" type, called "ILS", whose opening or closing is controlled by a magnet fixed on a drive wheel or a display wheel of counter located on the site, this first switch being placed in series with a first resistive impedance
R1 to form a series circuit whose two end terminals are able to be connected to two terminals for supplying electrical energy, constituting the two input terminals of the aforementioned transmission line;
a second electromagnetically controlled switch ILS2 connected to the terminals of this series circuit and able to be actuated by a disturbing external magnetic field; and
a second resistive impedance R2 also connected to the terminals of this series circuit and able to ensure the passage of a permanent current in the transmission line; and on the other hand, this measurement information accumulation device comprises:
two terminating terminals of the transmission line, the first of which is connected to a first output terminal of an electrical energy supply device, and the second of which is connected, through a third resistive impedance R3, to the second output terminal of this power supply device;
a counting device which is connected to this second arrival terminal and which thereby receives the pulses generated by the opening or closing of the first electromagnetic control switch ILS1; and
a window comparator circuit whose upper and lower thresholds define a correct operating window of the accumulation device, outside of which an alarm circuit or the like, connected to the output of this comparator, is triggered in the event of anomaly of the sensing device or the transmission line generated by a closure of the second ILS2 electromagnetic control switch or a cut or short circuit of this transmission line.

 Most advantageously, the first two resistive impedances mentioned above are bidirectional, so that the way in which the two extreme terminals of the aforementioned series circuit are respectively connected to the two aforementioned input terminals of the transmission line, has no effect on the operation of the device.

Preferably, in addition, this device comprises means for saving the operation of the measurement in the event of failure of the aforementioned electrical energy supply device, these means comprising:
a backup power supply capable of being switched in place of the failing power supply, having a terminal correspondingly replacing said first terminal of this faulty power supply, and another terminal corresponding to said second terminal of this faulty power supply and which is as for itself connected to said first terminal of the transmission line through a fourth resistive impedance R4 of a value much greater than that of the third resistive impedance R3 mentioned above;
means for not only switching these two power supplies, but also turning off said window comparator circuit and thus said alarm circuit; and
a non-linear resistive element, very preferably bidirectional itself, placed in series with the second resistive impedance between said terminals of said series circuit, said non-linear element being such that, under normal power supply, it has an impedance Z1 weak in front of said second resistive impedance R2 or such that the current passing through it results from the combination of its characteristics and the value of this second resistive impedance
R2, and such that, under backup power, it has another impedance Z2 large before this second resistive impedance R2 and large before the fourth resistive impedance R4 above, so that said counting device can then continue to operate without substantial consumption of current on the transmission line.

The accompanying drawing, given by way of example, will provide a better understanding of the invention, the characteristics it presents and the advantages that it is likely to provide.
Fig. 1 is a block diagram of an elementary embodiment of this remote power consumption measuring device;
Fig. 2 is a timing diagram facilitating understanding of the operation of the device of FIG. 1;
Fig. 3 is a schematic block diagram of a more advanced embodiment of this remote meter of energy consumption; and
Fig. 4 is a more detailed embodiment of the circuit according to FIG.

Referring first to fig. 1, this is an electrical device for remote measurement of a gas consumption, this device essentially comprising:
a consumption index capture device 1, which is integrated in the "gas meter" (not shown) located on the consumer's site;
a device 2 for accumulating the measurement information supplied for the sensing device 1, this accumulation device being located remotely in a site accessible to the agent responsible for reading the index, or in a central site grouping together for example all measurement index information relating to the subscribers of a given sector;
a two-wire line 3 for transmitting, to the totalizing system 2, measurement information provided by the sensing device 1; this line is for example a sealed underground line and carefully shielded.

 The capture proper is essentially to fix a magnetized plate (not shown) on the input wheel (corresponding in fact to the liters in most cases) of the totalizer mechanism of the gas meter, and arrange vis-à-vis , inside a compartment which is separated by a bulkhead from the possibly gas-filled atmosphere and enclosing the aforesaid totalizing mechanism, an electromagnetic switch with ILS1 flexible blades forming a sensor and able to be actuated, closed or at the opening according to the type of reed switch used, and through said watertight partition, during each passage of the magnetized wafer near this ILS1 reed switch. In the example shown here, it s' is a switch that operates at the opening, that is to say that is normally closed in the absence of magnetic stress and which opens under the action of such a request itation.

 The device 1, which is placed inside the aforesaid outboard compartment, constitutes an electrical box intended to be positioned as such in this compartment, and provided with two connection wires 4, 5 whose respective connection terminals 6, 7 are to be connected by the installer (for which no electricity specialist qualification is required) respectively to the two starting terminals 8, 9 of the transmission line 3, these two terminals being themselves permanently installed in this compartment outside -gas. As will be justified hereinafter, the terminals 6 and 7 can be indifferently connected respectively to the terminal 8 and the terminal 9, or to the opposite to the terminal 9 and to the terminal 8, so that a branching error n is not to be feared.

The electrical circuit 1 between the terminals 6 and 7 consists of the paralleling between these terminals of three branches.
a first branch constituted by placing in series the aforementioned switch ILS1 and a resistor R1 of for example a few kilohms;
a second branch comprising another flexible reed switch ILS2 which is placed at a sufficient distance from the switch ILS1 so as not to be actuated by the magnetized plate and which functions (in contrast to this particular example of the switch
ILS1) closing, that is to say that closes under the action of an external magnetic field, applied for example by a fraudster who would like to block the operation of the switch ILS1 and therefore that of the device of capture 1; and
a third branch comprising a resistor R2 which is preferably large in front of R1, and whose value is, for example, a few tens of kilohms, this resistor R2 ensuring the passage of a permanent current in line 3.

 The totalizing device 2 comprises a DC power supply having two sources of opposite polarities 10, providing on its two output terminals 11, 12 voltages that can be equal and opposite + V, -V equal for example to plus and minus 5 volts.

 Terminal 12 (voltage -V) is connected directly to the arrival terminal 40 of the two-wire line 3, while terminal 11 (voltage + V) is connected to the other end terminal 41 of this line across a protection resis tance R3 of for example ten kilohms.

 The upper terminal 40 is also connected firstly to the counting input 13 of a threshold electronic pulse counter 14, for example equal to 0 volts, and secondly to the two inputs 15 and 16 of a window comparator circuit 17 conventionally composed of a first analog comparator 18 defining the "low" threshold (su) of the window and a second analog comparator 19 defining the "high" threshold (S1) of the window, as well as of an "OR" circuit receiving the respective outputs 21, 22 of the threshold comparators 18, 19 and whose output 32 is applied to an alarm device 23.

Referring now also to FIG. 2, where the time is plotted on the abscissa and the voltages are plotted on the ordinate, the operation of the measuring installation of FIG. 1 is the following
In the absence of a disturbing magnetic field, the switch
ILS2 remains normally open. In line 3 circulates, in the absence of incident on it, a permanent current equal to

To this permanent current is added a pulse current due to the successive openings and closures of the switch ILS1 consecutive successive passages of the aforementioned magnetized plate in the immediate vicinity of this switch.

comptée par rapport au niveau -V où :

When the switch ILS1 is closed, the voltage (see curve 24 in FIG. 2) at the input 13 of the counter 14 is equal to

counted against the -V level where:

 The resistances are chosen so that this voltage VO is lower than the threshold of the counting input 13 (O volt), but remains, in absolute value, lower than the absolute value of the low threshold (S of the window comparator 17.

comptée par rapport au niveau -V > puis elle retombe à la valeur VO après passage de cette plaquette.When, following the passage of the magnetized plate, ILS1 comes to open (the switch ILS2 remaining open fact, mentioned above, it is located too far from this plate so that it has an influence on him), the voltage at the input 13 of the counter 14 passes abruptly to the positive value

counted in relation to the -V> level and then falls back to the VO value after passing this plate.

 This results in the input of this counter 14 a positive counting pulse 25 which increments it by one unit, and so on (pulses 26, 27, ...) for the following passages of the wafer in the vicinity of the switch ILS1.

 Note that the resistors are of course chosen so that the voltage + V1 is greater than the threshold of the counting input 13 and remains below the high threshold S1 of the window comparator 17.

 During a cut, accidental or malintentionnal, of the line 3, the input 16 of the comparator 19 is, through R3, brought to the voltage + V, which is greater than its triggering threshold S1, which leads to the appearance of a signal at 22, and, through the OR circuit 20, at 32. The alarm 23 is then activated (see the hatched portion 28 in the diagram of Figure 2).

 When closing the contact ILS2 under the influence of an external disturbing magnetic field, or during a short-circuiting (malintentionnal or not) of the line 3, the terminal 8 is directly connected to the voltage -V (the resistor R3 then fortunately limiting the current), which triggers the low threshold comparator 18, and therefore again the alarm 23 (see the hatched portion 29 in the diagram of Fig. 2).

 It should be noted that, since the three parallel branches of the sensing circuit 1 contain only bi-directional elements (resistors and / or switches), this circuit 1 is totally symmetrical and therefore operates in the same way, that terminal 6 is connected. at terminal 8 and terminal 7 at terminal 9 or vice versa.

 Referring to FIG. 3, it is a device similar to that of FIG. 1, but which is able to function, thanks to a backup power supply + Vs, -Vs relaying the normal power supply (+ V, -V) in case of failure of the latter, in a degraded mode in which the ancillary functions anomaly detection are abandoned while the consumption index reading function is maintained: If this operation in degraded mode can be maintained a sufficient number of hours (about ten hours for example), we can hope be able to ensure the restoration of the main supply without loss of consumption record, which is the essential.

 As this backup power supply generally consists of a set of backup storage batteries, it is essential, in order not to discharge these batteries too quickly, that the backup power supply does not provide, in contrast to the main power supply. , permanent current on line 3.

For this purpose, the circuit of FIG. 3 differs from that of FIG. 1 by the triple fact
a switching device is provided (here constituted by two simple but inverse contactors 30, 31 and by a two-way contactor 33, all three controlled by an output 34 of the electronic power supply and control unit 10) capable of to switch, in case of failure of the main power supply, this supply + V, -V on a backup supply (or backup) + V5, -V (terminal them and 12s);
s
- a protection resistance R4 much higher than R3
(For example of the order of a hundred times greater) is connected between the positive terminal 11 (+ Vs) of the backup power supply and the terminal 40; and
- A non-linear resistive element 35, very preferably bidirectional too to maintain the above property of interconnection independence of terminal pairs 6, 7 and 8, 9, is placed in the same branch as R2, in series with it.

The voltages V and V are such that, under normal power supply
s + V, -V, the non-linear element 35 has an impedance Z1 which is very small in front of R2 (for example a few ohms), while under backup power supply + V5, -Vs, it has an impedance Z2 which is at both large before R2 and R4 (for example ten megohms).

 Moreover, in case of failure of the main power supply + V, -V, the threshold comparators 18, 19 which are normally powered by this main power supply and are then not switched to + Vs, -Vs, are obviously set then out of order.

When switching to backup power, the operation of the device of FIG. 3 is the following
the anomaly detection device (ILS2, 15 to 23) no longer functions;
the permanent current in line 3 has a negligible value;
when ILS1 is closed, the input voltage of the counter 14 at this low level is close to -Vs, and remains (by a consequent choice of the value of -Vs) lower than its counting threshold;
when ILS1 is open, the voltage at 13 is close to + V
it is greater than its threshold so that, again, the opening of ILS1 remotely increments the counter 14 by one unit.

 A practical example, particularly simple and advantageous embodiment of the circuit of Figure 3 is shown in FIG. 4, which will be referred to now.

 In this embodiment, the normal power supply is always constituted by a symmetrical power supply with respect to the ground: -V applied between the terminals 11 and 12. On the other hand, the backup power supply consists of a power supply taken between on the one hand a positive terminal they brought to + Vs and the other mass, that is to say in fact between the terminals 11s and 12, considering that, if the normal power supply is out of circuit this terminal 12 is necessarily connected to ground by the resistor Req of the normally polarized circuits between the terminal 12 and the ground when the circuits of the normal power supply are no longer fed between -V and the ground.Optionally, this mass return is anyway guaranteed by a resistance R5 of a few kilohms (of the same order of magnitude as R2 and in any case weak in front of R4) connected between the terminal 12 and the mass as shown in the drawing: this resistance R5 comes in parallel on the resistance this Req above.

Furthermore, the resistors R3 and R4 are respectively fed respectively through a diode D1, D2, D1 being connected directly between the terminal 11 and R3 and D2 being connected live between 11s and R3. In addition, the value of the voltage + V relative to the
s mass is equal to that of the voltage + V with respect to the mass. Under these conditions, no active switching device (such as the device 30, 31, 33 of Fig. 3) is necessary since, in case of failure of + V, -V, switching to + Vs, O volts is automatically performed thanks to the presence of diodes D2 and D1: when everything is normal, the installation is theoretically powered, on the positive side, both + V and -Vs, but + V practically plays
ss no role given the very high value of R4 compared to
R3, on the contrary, when + V, -V no longer works, + Vs automatically takes over through D2, while D1 is then blocked as reverse biased. In the foregoing, the waste voltage of diodes D1, D2 has been neglected to simplify the disclosure.

In this embodiment, the nonlinear element 35 is constituted by a Zener diode voltage limiting component, and preferably as shown, by a set of two similar Zener diodes DZ1, DZ2 connected in series and head to tail as shown. , which makes it possible to ensure the aforementioned advantageous symmetry of the nonlinear element 35. For example, the diodes DZ1 and DZ2 are diodes
Zener "BZ X 85C" of RTC, having a leakage current of the order of microampere. These Zener diodes are not arbitrary because they are chosen such that their Zener voltage V is greater than or equal to the value Vs of the backup power supply, while remaining less than the value 2V of the main power supply. For example, the main power supply is a balanced power supply
+ V, -V = +5 volts, -5 volts while backup power is a power supply
+ Vs, O = +5 volts, 0 volts and the Zener diodes DZ1, DZ2, have a Zener voltage V of
z the order of 7 volts.

Finally, in this embodiment, the resistors R2 and R3 are chosen equal, which allows to enter, as will be seen below, in all cases on a counter 14 powered at +5 volts / 0 volt (ie + V / 0 volts in normal operation, ie + V / 0 volts in operation under backup power). The
s counting threshold of this counter 14 is then obviously chosen greater than 0 volts.

The operation of the circuit of FIG. 4 is the following
In the case of normal operation, the steady current I in line 3 is equal to the difference between the supply voltage and the Zener voltage Vz, divided by the sum of the resistors R2 and R3 (the waste voltage of the other Zener diode being neglected)

The high voltage level at the input of the counter 14, counted relative to the -V level, is then equal to V + RI
z 2
The low level, also counted relative to the -V level, is equal to:

 (2V: symmetrical power supply + V, -V).

 In this particular case, R1 is chosen equal to R3, so that this low level is zero vott, which makes compatible the use of a counter 14 supplied with + V / 0 volts, ie under +5 volts / 0 volt.

When the + V, -V source is switched off or when it is restored, switching of the + V, -V and + V5, 0 supplies is performed automatically and without any active hardware switching, thanks to diodes D1 and
D2 in series on these two sources. The back-up of the backup power supply (between 12 and ground) is performed by the resistors R5 and Req in parallel.

The Zener voltage V being chosen greater than or equal to Vs,
z the equivalent resistance, under + V / 0 volts, of the element 35 is
s determined by the leakage current Io of these Zener diodes: it is in any case large in front of R4. The input voltage of the counter 14 (high level) which is obtained when ILS1 is open, and then equal to V - R4.Io.

s
It is understood that the input impedances 13 of the counter, 15 and 16 of the window comparator are large in front of R4.

This input voltage is close to ground (low level) when
ILS1 is closed, given that R4 is much higher than
R1, Req, and R5: under backup power supply, the counter 14, whose counting threshold is for example chosen at a substantially median value between 0 volts and + Vs volts, therefore works in the same way as normal power supply.

 It must also be understood that the foregoing description has been given by way of example only and that it in no way limits the scope of the invention which could not be overcome by replacing the execution details described. by all other equivalents.

Claims (9)

R E V E N D I C A T I O N S CLAIMS  1. Device for remotely measuring a power consumption comprising a device (1) for capturing a consumption index which is integrated in the "counter" located at the consumer site, a device (2) for accumulating measurement information provided by this sensing device (1), this accumulation device (2) being located at a distance, and a line (3) for transmitting this measurement information from this sensing device (1) to this accumulation device (2) characterized in that on the one hand this sensing device (1) comprises ::  a first electromagnetically controlled switch (ILS1), of the "Flexible Blade Switch" or "ILS" type, the opening or closing of which is controlled by a magnet fixed to a display wheel or a wheel; counter drive located on the site, this first switch (ILS1) being placed in series with a first resistive impedance (R1) to constitute a series circuit whose two end terminals (6, 7) are able to be connected to two terminals electric power supply (8, 9) constituting the two input terminals of the transmission line (3);  a second electromagnetically controlled switch (ILS2) connected to the terminals (6, 7) of this series circuit (R1, ILS1) and only able to be actuated by a disturbing external magnetic field; and  a second resistive impedance (R2) also connected to the terminals (6, 7) of this series circuit (R1, ILS1), and capable of ensuring the passage of a permanent current in the transmission line (3) and in that whereas, on the other hand, this information accumulation device (2) comprises  two terminals (40, 41) for the arrival of the transmission line (3), one of which (41) is connected to a first output terminal (12) of an electrical power supply device (10), and the other (40) is connected, through a third resistive impedance (R3), to the other output terminal (11) of this power supply device (10)  - a counting device (14) which is connected to this other arrival terminal (40) and which thereby receives the pulses in gendrée by the opening or closing of the first electromagnetically controlled switch (ILS1); and  - a window comparator circuit (17) whose high and low thresholds tSo, S1) define a correct operating window of the accumulation device (2), outside of which an alarm circuit (23), or the like, connected to the output (32) of this window comparator (17), is triggered in case of anomaly of the sensing device (1) or the transmission line (3), which anomaly would be generated by a closure, due to a disturbing external magnetic field, the second electromagnetically controlled switch (ILS2), or a cut or short circuit of the transmission line (3).  2. Device according to claim 1, characterized in that the first two resistive impedances (R1, R2) are bidirectional elements, so that the direction of connection of the terminals (6, 7) of the sensing device (1) to those (8, 9) of the line (3), is indifferent.  3. Device according to claim 1 or claim 2, characterized in that it comprises means for saving the operation of the power consumption measurement in case of failure of the power supply (+ V, -V) in electrical energy. of the device, these means comprising  a backup power supply (+ seen, -Vs), able to be switched in place of the faulty power supply (+ V, -V), with a first terminal (12s) correspondingly replacing said first terminal (12) of the faulty power supply, and another terminal (ls) which corresponds to the other terminal (11) of this faulty power supply and which is connected to said other terminal (40) of arrival of the transmission line (3) through a fourth resistive impedance (R4) of much higher value than that of the third im  4 aforementioned resistive pacing (R3);  means (+ V, -V, 34) for not only switching these two power supplies (+ V, -V on + V5, -V5), but also switching off the window comparator (17) and the device alarm (23); and  - a non-linear resistive element (35) placed in series with the second resistive impedance (R2) between the terminals (6, 7) of the aforesaid circuits, this non-linear element (35) being such that, under normal power supply (+ V, -V), it has a low impedance (Z1) in front of said second resistive impedance (ru), or such that the current flowing through it results from the combination of its characteristics and the value of this second resistive impedance (R2), and such that, under backup power supply (+ Vs, -Vs), it has a large impedance (Z2) in front of this second resistive impedance (R2) and large in front of the aforementioned fourth resistive impedance (R4), so that said counting (14) can then continue to operate under backup power (+ seen, -V) and without consumption  s substantial current on the transmission line (3).  4. Device according to claim 3, characterized in that this non-linear element (35), active or passive is a bidirectional element.  5. Device according to claim 3 or claim 4, characterized in that said non-linear element (35) comprises at least one Zener diode whose Zener voltage is of amplitude less than that of the normal supply voltage ( + V, -V), but greater than or equal to that of the backup voltage (+ Vs, -V).  s  6. Device according to claim 5, characterized in that the non-linear element (35) comprises two similar zener diodes (DZ1, DZ2) connected in series and head to tail.  7. Device according to one of claims 3 to 6, characterized in that said first terminals (12s and 12) of the backup power supply (+ seen, -Vs) and the normal power supply (+ V, -V ) are combined into one (12), and in that the third (R3) and fourth (R4) resistive impedances mentioned above are each fed through a respective diode (D1, D2) connected directly, so that the failure of the normal power supply (+ V, -V) ipso-facto causes the power supply of the device through the backup power supply (+ V5, O volt) alone.  s normal diet are equal.  8. Device according to claim 7, characterized in that the positive values (+ V, + V) of the backup power supply and  9. Device according to claim 8, characterized in that, the normal power being a symmetrical power supply (+ V, -V) with respect to the ground, said first (R1) and third (R3) resistive impedances are chosen substantially equal. , which allows the use of a counting device (14) supplied in all cases under said positive value (+ V or + Vs) and the mass.