CH662144A5 - CONTROL CIRCUIT FOR A SANITARY FITTING. - Google Patents

Description

The invention relates to a control circuit for a sanitary fitting, with which the flow of at least one water flow through a sanitary fitting can be controlled; with a power supply part; with a sensor circuit which outputs an output signal during the duration of the presence of a user in the sensitivity range of a sensor; with a logic and driver circuit that receives the output signal of the sensor circuit, contains a driver stage for the solenoid of a solenoid valve or relay for each water flow to be controlled and determines the logic according to which the water flows are controlled.

In the case of sanitary fittings, which were equipped with the known control circuits of this type, it was sometimes observed that the water began to flow surprisingly and without a recognizable external reason, without a user being in the sensitivity range of the sensor. Such false triggers are very annoying for several reasons: on the one hand, they may mean a not to be neglected water loss, especially since the minimum duration of the water flow is determined by a waste delay circuit and can be several seconds. On the other hand, the confidence of the user in the reliability of such fittings is generally shaken.

The object of the present invention is to design a control circuit of the type mentioned at the outset in such a way that undesired false trips are avoided.

This object is achieved according to the invention in that the voltage supply part contains a monitoring circuit which monitors the amplitude of the operating voltage and in the event of an increase in this amplitude by a certain amount within a certain time, inactivates the logic and driver circuit such that even when an output signal of the No magnetic coil (s) is (are) energized.

The invention is based on the knowledge that the incorrect triggering of known sanitary fittings is based on changes in the operating voltage, which can be caused, for example, by switching on a large consumer in the home. In such a case, if the supply voltage of the control circuit breaks down to such an extent that the sensor circuit becomes inoperable, then when the voltage rises again to its original, normal value, the various internal voltages of the sensor circuit have to be readjusted. In the case of highly sensitive sensor circuits in particular, this then leads to output signals being emitted, even if there is no real signal from the sensor itself. Similar processes can also occur when the control circuit is switched on.

For this reason, the monitoring circuit is provided according to the invention within the voltage supply part. Since the undesired false trips only occur during the (re) rise in the operating voltage, this additional circuit only responds to an increase in the operating voltage; it is insensitive to small changes in the operating voltages or those that occur over very long periods of time, and to a drop in the operating voltage. It is crucial that the monitoring circuit does not deactivate the sensor circuit itself, which is basically influenced by the voltage variations, but rather the logic and driver circuit, which is connected downstream of the sensor circuit. Otherwise it would not be possible to bring about the steady state of the different voltages within the sensor circuit without false impulses.

There are various options for the operating mechanism of the monitoring circuit: For example, when the monitoring circuit is activated, the voltage supply to the solenoid coil (s) or the voltage supply to the logic and driver circuit can be interrupted.

However, it is particularly advantageous if, when the monitoring circuit responds, a control voltage required to operate the logic and driver circuit

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is suppressed. In this case, the currents that can be controlled by the monitoring circuit are particularly small.

The monitoring circuit can respond to an increase in the rectified operating voltage, so it does not need to monitor the mains voltage itself.

In a particularly advantageous embodiment, the monitoring circuit comprises:

a first capacitor, the first electrode of which the rectified operating voltage is supplied;

a first diode whose cathode is connected to the second electrode of the first capacitor and whose anode is connected to ground;

a second diode whose anode is connected to the connection point between the first capacitor and the first diode;

a second capacitor having one electrode connected to the cathode of the second diode and the other electrode connected to ground;

a first resistor in parallel with the second capacitor;

a controllable switch, one contact of which is connected to a point in the logic and driver circuit which carries the control voltage required for operation, and the second contact of which is connected to ground and which is driven by the voltage on the second capacitor.

Embodiments of the invention are explained in more detail below with reference to the drawing; show it

Figure 1 schematically shows a control circuit for sanitary fittings, partly as a block diagram;

FIG. 2 shows a more specific embodiment of the circuit arrangement from FIG. 1.

The control circuit shown in FIG. 1 for a sanitary fitting comprises in a known manner a sensor circuit 1, which is supplied by the operating voltage Vo. This is provided by the voltage supply part 10 described in more detail below. Within the sensor circuit 1 are all those circuits and components which are required to generate a signal indicating the presence of the user of the sanitary fitting. All circuit arrangements working with radiation of any kind (electromagnetic radiation of the most varied wavelengths or sound) are a transmitter, a receiver which detects the radiation emitted and possibly reflected radiation, and, under certain circumstances, suitable preamplifiers and the like. Purely capacitive sensor circuits, which in addition to the capacitive sensor essentially only comprise a suitable amplifier, can also be used in the circuit arrangement shown. The only decisive factor is that a characteristic change in the output signal takes place at the output A of the sensor circuit 1 while a user is in the sensitivity range of the sensor.

In the example shown it is assumed that the potential at the output A of the sensor circuit 1 is at a high value H as long as the control circuit is at rest and drops to a lower value L for the duration of the presence of a user.

In the sensor circuit 1, a drop delay circuit can also be included, which extends the output signal A by a certain period of time beyond the duration of the presence of the user, so that the fitting continues to run during this period when the user is already moving out of the sensitivity range of the sensor Has.

The output signal A of the sensor circuit 1 is fed to the input E of a logic and driver circuit 2. As the name suggests, this contains the driver stage (s) for the

Operation of the solenoid coil (s), which actuate the solenoid valves controlling the water flow (possibly via relays). In the case shown, two magnetic coils 3 and 4 are provided, with which a cold water flow and a hot water flow are controlled. In the exemplary embodiment, this is done according to a certain logic, which is explained below, but which is not important in detail. The solenoids 3 and 4 are connected to a supply voltage Vi which generally does not match the supply voltage V0 of the sensor circuit. A safety diode D1 or D2 is connected in parallel to each of them.

The voltages V0 and Vh, which are used to operate the sensor circuit 1 and the logic and driver circuit 2, including the magnet coils 3 and 4, come from a power supply part, which is provided with the reference number 10, as already mentioned.

The alternating voltage, which may already be reduced from the mains voltage to a lower value, is fed to an autotransformer 11, from which the voltage value required for operating the downstream components is tapped. This voltage is rectified by diode D6 and smoothed by capacitor C2. The unstabilized DC voltage obtained in this way is supplied as the supply voltage V] to the solenoids 3 and 4 and to the input of a voltage stabilizer 12. The latter can be an integrated circuit of a known type. The voltage V0 required for the operation of the sensor circuit 1 and the logic and driver circuit 2 appears at the output of the voltage stabilizer 12 which is short-circuited in terms of alternating current by the capacitor C3.

A monitoring circuit 13 (with a dashed outline) for the amplitude of the operating voltage is also integrated in the voltage supply part 10. This includes the capacitors C4 and C5, the diodes D7 and D8, the resistors R8 and R9 and the transistor T6.

The capacitor C4 is connected with one electrode to the voltage Vb with the other electrode to the cathode of the diode D7 and the anode of the diode D8. The anode of diode D7 is grounded.

The cathode of the diode D8 is connected to an electrode of the capacitor C5, the other electrode of which is also grounded. The resistor R8 is connected in parallel with the capacitor CS as a discharge resistor. The voltage across the capacitor C5 is supplied through the resistor R9 to the base of the transistor T6. Its emitter is connected to ground, while the collector is connected to an input I of the logic and driver circuit 2.

The function of the circuit arrangement described in the stationary state, that is to say a long time after the last major change in the amplitude of the operating voltage V, is as follows:

If a user (or the hand of a user) moves into the sensitivity range of the sensor and consequently an output signal A occurs at the output of the sensor circuit 1, the logic and driver circuit 2 first energizes the magnetic coil 3, which causes the cold water to flow. This happens regardless of whether the previous user last tapped cold or hot water. With the logic adopted here, hot water only begins to flow after a conscious decision and a deliberate action by the user.

If there is a major change in the amplitude of the operating voltage V, be it when switching on or in the event of a brief breakdown of the mains voltage, there is a risk that the sensitive sensor circuit 1 will emit an output signal even though there is no user in the sensitivity range of the sensor. As a result, the sanitary fitting is surprising and undesirable

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Water leaks.

Since the false triggers are caused by the rise in the operating voltage to the normal value (the sensor circuit 1 becomes inoperative when the value falls below the normal value), the monitoring circuit 13 responds when the amplitude of the operating voltage V changes within a certain time by a certain amount enlarged. Short-term, small changes and a drop in the operating voltage V are not taken into account.

When the monitoring circuit 13 responds, the logic and driver circuit 2 is deactivated, while the sensor circuit 1 remains fully functional. It is therefore still accepted that the sensor circuit emits 1 false pulses; however, the processing of these false impulses in the logic and driver circuit 2 is prevented. This can be done by interrupting the operating voltage Vi (or the connection to ground). In the example shown, however, a control voltage required to trigger the logic and driver circuit 2 is short-circuited. This is the more economical way because the currents to be controlled by the monitoring circuit 13 are smaller.

The interruption of the supply voltage V0 for the sensor circuit 1, on the other hand, is not a feasible route, since the voltage instabilities within the sensor circuit 1 that lead to false tripping are only delayed, but not avoided.

To understand the function of the monitoring circuit 13, first consider the steady state in which the operating voltages V, V0 and Vi have had their normal value for a long time. In this state, the capacitor C4 has charged to the voltage Vi. The capacitor C5, however, is completely discharged. The base of transistor T6 is at ground potential; the transistor T6 therefore does not conduct.

The input I of the logic and driver circuit 2 is connected to an internal circuit point which carries a control voltage required for the operation of the logic and driver circuit 2. As long as the transistor T6 blocks, this control voltage remains unaffected; logic and driver stage 2 works normally.

The turn-on phase of the control circuit will be described next.

First of all, the operating voltage V is 0; capacitors C4 and C5 are discharged. If the operating voltage V is now applied, not only the capacitor C4 charges. Since the capacitor C5 cannot discharge as quickly as desired via the resistor R8, it is also temporarily charged. This means that the voltage at the base of transistor T6 temporarily becomes positive so that transistor T6 becomes conductive. Due to the connection to input I of logic and driver circuit 2, this results in

that the control voltage required for operation is short-circuited: the logic and driver circuit 2 is deactivated for the time during which the transistor T6 is conducting. Pulses A arriving from sensor circuit 1 are not processed any further.

The time in which the transistor T6 conducts is determined by the values of the capacitors C4 and C5 and of the resistor R8. It is set in such a way that the internal voltages of the sensor circuit 1 are stabilized after the expiry and no false impulses are to be feared.

The mode of operation in the event of a brief breakdown of the operating voltage, for example when switching on a larger consumer (elevator, etc.) is as follows:

The capacitor C4, which is initially charged to the full voltage Vi, discharges via the diode D7 to the now smaller value. The capacitor C5 remains discharged during this process. The transistor T6 turns off. Only when the voltage Vi rises again to the full value does the capacitor C5 charge briefly in the manner described above. As a result, the transistor T6 conducts for a certain period of time and inactivates the logic and driver circuit 2 by short-circuiting the corresponding control voltage.

FIG. 2 shows a detailed embodiment of the logic and driver circuit 2 from FIG. 1, on which the mode of operation of the monitoring circuit 13 becomes clear by way of example. The circuit elements 1, 3, 4, 10 and D1 and D2 are unchanged from FIG. 1.

The input E of the logic and driver circuit 2 is connected to the base of the transistor T1. Its collector is connected to the positive supply voltage V0 via the resistor R1; the emitter is directly at ground. The collector of T1 is also connected to the base of a second transistor T2 via a Zener diode Z2 and to ground via a capacitor C1 which determines the pickup behavior of the circuit. The collector of T2 is located directly at the output F, which leads to the cold water solenoid 3. The emitter of T2 is connected to ground via the emitter-collector path of a third transistor T3 and a resistor R2 lying parallel to it.

The base of the transistor T3 is connected via a resistor R3 to the collector of a fourth transistor T4, which is also located directly at the output G for the hot water magnet coil 4. The emitter of T4 is connected directly to ground, the base via a resistor R4 to the collector of a fifth transistor T5 and from there via a resistor R5 to ground. The emitter of transistor T5, which, in contrast to transistors TI to T4, is a pnp transistor, is connected directly to the collector of transistor T1. The base of transistor T5 is connected via diode D5 and resistor R6 to the collector of transistor T4 and via resistor R7 to a button 5, the second contact of which is connected to ground.

The function of the circuit arrangement from FIG. 2 in the stationary state is as follows:

First, consider the idle state in which the sensor circuit 1 delivers an output signal A with the high value H. Since the transistor T1 then conducts, its collector is practically at ground potential. Furthermore, since all the control voltages for the driver transistors T2 to T4 are derived from the collector of the transistor T1, as will become clear later, they block. The solenoids 3 and 4 remain de-energized; no water flows out of the sanitary fitting.

The collector of the transistor T1 is also connected to the collector of the transistor T6 of the monitoring circuit 13, thus corresponds to the input I of the logic and driver circuit 2 from FIG. 1.

Now when a user steps on the sanitary fitting and puts his hands in the sensitivity range of the sensor, the output signal of the sensor circuit changes from the value H to the lower value L. This has the consequence that the transistor Tl blocks and its collector voltage has a relatively high positive value assumes. The capacitor C1 begins to charge. As soon as the voltage across capacitor C1 minus the voltage drop across Zener diode Z2 exceeds the switching voltage of transistor T2, it becomes conductive. The current flow to the cold water magnet coil 3 now depends exclusively on the switching state of the transistor T3 and thus on its base voltage.

The base of the transistor T3 is connected via the resistor R3 to a voltage divider, which is separated from the hot water magnet coil 4 and the emitter-collector path

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Transistor T4 is formed. For reasons that will be explained below, transistor T4 is not conductive at this time. This means that the base of the transistor T3 gets enough voltage to turn on the transistor T3. The current path from the positive supply voltage Vi via the cold water magnet coil 3 and the emitter-collector paths of the two transistors T2 and T3 is thus free. The solenoid valve picks up: cold water flows.

The control voltage of the driver transistor T4 is determined by a voltage divider, which is formed by the emitter-collector path of the transistor T5 and the resistor R5. Because the base of transistor T5 (which, as mentioned, is a pnp transistor) is at substantially the same potential as the collector of transistor T4, transistor T5 turns off. The base of the transistor T4 is practically at ground potential, which explains its blocking state in the operating phase currently described. The hot water solenoid 4 thus remains de-energized.

The situation is obviously such that the control voltages of the transistors T3 and T5 are dependent on the collector voltage of the transistor T4. However, since the base voltage of transistor T4 in turn depends on the switching state of transistor T5, it is a function of its own collector voltage. In this way, a self-holding circuit results, which - depending on the initial condition - can assume two different circuit states.

The state described above, in which the transistor 3 conducts, but the transistor 4 does not, arises automatically after the previous idle state of the control circuit, because in the idle state the transistor T4 was not conductive. In this way, the cold water flow always has “priority” over the hot water flow: cold water always flows without any special action on the part of the user.

If the user now wants to switch to warm water, he briefly presses button 5 and thereby sets a new initial condition for the self-holding circuit: the voltage at 5 of the base of transistor T5 is drawn closer to ground potential; transistor T5 begins to conduct. This makes the base voltage of transistor T4 more positive; The transistor T4 begins to conduct: a current also flows through the hot water magnet coil 4, which causes hot water to escape from the sanitary fitting.

When the transistor T4 is conductive, a collector voltage is much lower than before in the off state. This has two consequences: firstly, the voltage at the base of transistor T3 is no longer sufficient to turn it on. i5 The current flow through the transistors T2 and T3 and the magnetic coil 3 stops. Cold water no longer flows out. On the other hand, the transistor T5 keeps itself conductive because of the connection of its base to the collector of the transistor T4, even if the user has released the key 5. To understand the function of the monitoring circuit 13 in the switch-on phase and in the event of fluctuations in the operating voltage V, it should first be pointed out that the emitter-collector path of the transistor T6 is parallel to the emitter-collector path of the transistor T6 and is parallel to the 25 emitter-collector path of the transistor Tl. As long as the transistor T6 conducts (and this is precisely the case, as explained above, in the "critical" period), no control voltage can develop at the collector of the transistor Tl, even if the sensor circuit is a "real" 30 or Outputs the "wrong" output signal A and thereby blocks the transistor T1.

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2 sheets of drawings

Claims (6)

662144 1. Control circuit for a sanitary fitting, with which the flow of at least one water flow through the sanitary fitting can be controlled, with a voltage supply part; with a sensor circuit which outputs an output signal during the duration of the presence of a user in the sensitivity range of a sensor; with a logic and driver circuit that receives the output signal of the sensor circuit, contains a driver stage for the solenoid coil of a solenoid valve or relay for each water flow to be controlled and determines the logic according to which the water flows are controlled, characterized in that the voltage supply part (10) contains a monitoring circuit (13) which monitors the amplitude of the operating voltage (V) and inactivates the logic and driver circuit (2) in such a way that this amplitude increases within a certain time in such a way that even when an output signal (A) is present of the sensor circuit (1) no solenoid coil (s) (3,4) is (are) energized. 2. Control circuit according to claim 1, characterized in that when the monitoring circuit (13) responds, the voltage supply to the solenoid (s) (3, 4) is interrupted. 2nd PATENT CLAIMS 3. Control circuit according to claim 1, characterized in that when the monitoring circuit (13) responds, the voltage supply to the logic and driver circuit (2) is interrupted. 4. Control circuit according to claim 1, characterized in that when the monitoring circuit (13) responds, a control voltage required for operating the logic and driver circuit (2) is suppressed. 5. Control circuit according to one of the preceding claims, characterized in that the monitoring circuit (13) responds to an increase in the rectified operating voltage (Vi). 6. Control circuit according to claim 5, characterized in that the monitoring circuit (13) comprises: a first capacitor (C4), the first electrode of which is supplied with the rectified operating voltage (V,); a first diode (D7) whose cathode is connected to the second electrode of the first capacitor (C4) and whose anode is connected to ground; a second diode (D8) whose anode is connected to the connection point between the first capacitor (C4) and the first diode (D7); a second capacitor (C5) having one electrode connected to the cathode of the second diode (D8) and the other electrode connected to ground; a first resistor (R8) connected in parallel with the second capacitor (C5); a controllable switch (6), one contact of which is connected to a point (I) in the logic and driver circuit (2) which carries the control voltage required for operation, the second contact of which is connected to ground and which is dependent on the voltage on the second capacitor ( C5) is controlled.