IL103953A - System for measuring and monitoring the quantity and temperature of hot water in a boiler - Google Patents

Description

n^ M-i-i imma&Dm tpjonn o>on rn»:> mp.i i n*r>io imyo A SYSTEM FOR MEASURING AND MONITORING THE QUANTITY AND TEMPERATURE OF HOT WATER IN A BOILER A SYSTEM FOR MEASURING AND MONITORING THE QUANTITY AND TEMPERATURE OF HOT WATER IN A BOILER Field of the Invention The present invention relates to a system for measuring and monitoring the quantity of hot water in a boiler. Said system can provide information in real time about the state of the water in the boiler (temperature in relation to water quantity ) .

Background of the Invention There are many different types of domestic boilers, with and without an attached solar panel. Most of them have an attached electric switch and a thermostat inside.

When one turns on the electricity, a red light lights up. However, this doesn't yet indicate if the electric heating device is on or if the thermostat has turned it off after reaching the temperature for which it was set. When the thermostat turns the electricity (and heating) off the red light is still on.

Israel Patent number 45310 provides some response to this problem. This patent is a simple electric circuit that turns the red light off when the thermostat turns the boiler off. According to the above-mentioned patent the user only knows if there is a maximum quantity of hot water (according to the thermostat's setting) but the user cannot know any other important details about the hot water, such as if the solar system can still generate more hot water, or if before the red light goes off he already has enough hot water for his current need.

Another product that improves the use of the home boiler in some way is known as "MADOOD" . This is simply a "SHABBAT CLOCK" attached directly to the electric switch of the boiler, with which one can decide in advance when, and for how long should the additional electric heat work. But the decision is not derived from any analysis of the real situation inside the boiler.

The system according to the present invention overcomes the disadvantages of the above-mentioned known systems.

For. example, according to the present invention one can know if there is or isn't enough hot water for showering. Furthermore, one can know how many showers can be taken.

Further advantages of the present invention over the prior art are the saving of electricity and time by allowing one to program and order in advance the shower he wants to take later on (e.g. at a time one returns from work, or from the seashore with a known number of persons who will need a warm shower) . bursting the water pipes in the solar heaters.

Brief Description of the Invention The present invention relates to a system for monitoring and measuring the quantity and temperature of hot water in a boiler comprising a plurality of temperature sensors installed inside a boiler; a converter that converts said sensors output to pulses or to another binary code readable by a controller capable of counting or decoding said converter output; and •r having a relay that turns the boilers electric heating on and off; and a user interface unit connected to said controller.

Detailed Description of the Invention The present invention will be better understood, and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the drawings herein appended.

Figure 1 is a block diagram illustrating the main components of the system.

Figure 2 illustrates the probe in the boiler.

Figure 3 illustrates the fitting of the probe to the boiler.

Figure 4a illustrates the probe and sensors from the above.

Figure 6 details the controller unit.

Figure 7 shows the user interface circuit.

Figure 8 outlines the front panel of the instrument.

Figure 9 shows the user interface flow chart.

The system according to the present invention is designed to give its users information and control of their water heating boiler.

The system can display real time information about the condition in the boiler (temperature vs. water quantity).

It can accept and store a number of user programs and execute them while taking into account solar heating and minimizing electricity consumption. (A program is a request of a certain quantity of water, or time of water outflow, in a certain temperature at a certain time).

Programs stored in memory can be displayed and executed according to the user's choice.

The system can calculate and display information such as water and electricity consumption per water outflow (or shower) .

When the water in the boiler, or in pipes around it, reaches freezing temperature the system can set an alarm, or just start the electric heating in order to prevent the Figure T illustrates a block diagram of the system of the present invention comprising the following main components: (a) The probe (1) inserted in the boiler, (b) A converter/ transmitter (2), (c) A controller (3), and (d) User interface (4) . a . The probe The probe is a single unit inserted in the boiler either as a retrofit, or in boiler production. It incorporates a number of sensors in order to measure the temperature at a • r number of points in the boiler.

When the height of the boiler is longer than its horizontal dimension, the probe may be inserted vertically anywhere in the boiler without being affected by horizontal temperature gradients. This is because of the stratification which takes place in a boiler, causing the existence of layers of water whose temperature is dependent on their vertical location only (Figure 2 illustrates the probe in the boiler) .

When the horizontal dimension is larger than its vertical dimension, there may be more of a horizontal gradient due to the distance and accordingly it may be necessary to insert two probes .

The probe consists of a thin tube nearly as long as the inner length (height) of the boiler. For optimal accuracy the transmitter.

The whole assembly is both waterproof and protected from corrosion. It is made of materials which are insensitive to the working temperature range of the boiler.

Internally the probe may be said to consist of two sections, the one being the probe proper, the second being the fitting by means of which it is attached to the boiler.

The fitting provides a sealed point of entry for the information cables into the probe proper. It is designed to ■r enable quick and easy installment by disconnecting the extending water pipe and inserting the fitting by means of standard threaded joints. The probe is sufficiently thin in order not to hamper the water flow. The fitting is shown in Figure 3.

In the most common types of boilers the possible apertures for installment are either the hot water exit pipe or, where a solar panel is attached, the circulation exit pipe.

An additional sensor is installed measuring the cold water temperature for use in the calculation of the warm water outflow (shower time). This sensor may be attached at the cold water pipe (protected) in such a spot as will ascertain a correct measurement of the temperature. It is independent The calculation method is as follows: The temperature between the points of measurement is calculated by the method of linear interpolation. Since the natural stratification of a gradual heating of the water forms a smooth temperature profile according to height, this method does not cause a significant error.

The temperature at the boiler edges is approximated according to a given mathematic formula.

An additional sensor measures the temperature of the cold ■ r water added to the expected output of hot water (Tc) .

The desired water temperature is defined externally by the user (Tr) .

The calculation of the water volume in the desired temperature (Tr) is attained according to the formula: Where : x is in the direction of the boiler height T is the temperature at every x according to the interpolation formula.

A is the horizontal area of a cross section of the boiler.

The time of hot water outflow is calculated according to: t = Vtr s obtain the desired time of use of hot water, the calculation is : 1 ) Vr according to the desired time of hot water outflow 2) Va = Vr - V(Tr) 3) CP * (Tr - Tc)* Va*p W Where : th is the time of the use of electricity W is capacity of the electric heater Cp is the water specific temperature P is the water density. ,r In this design we use thermistors, but different types of sensors such as thermocouple etc. can be used with little changes in the electronics. b. The Converter The convertor converts the sensors output (resistance) to pulses which can be counted by the controller.

Figure 5 shows the electrical design of the converter - U1 is an oscillator generating a pulse every 2 seconds; these pulses are counted by 3 bit counter U2 and used to select a channel of the analog switch U3.

U4 is a monostable multivibrator which generates a pulse relative in duration to external resistor and capacitor, the external resistor is a thermistor selected by U3 and thus the U5 is an oscillator generating square wave of 50 kHz, the pulses of U5 are ANDed logically with the pulse from U4, the output of the AND gate U6 is a number of pulses relative to the temperature measured by the currently selected thermistor.

Transistor Q1 is used to drive a wire to transmit the pulses from the converter located near the boiler to the controller located in the users home.

J1 : : n Output of Ul Every 2 sec Output of U4 Relative to temp .

Output of U5 50 kHz J ULTLnJl 0utput o£ converter Time The full array of cables, both the power lead and the information cable connecting between the convertor/transmitter and the controller is pulled through the existing duct, in use for the power cable. c. The Controller The controller unit is a Single Board Computer (SBC) such as Intel's 80C31 microcontroller. The board includes an eeprom chip (27C64) that contains the software. There is a power regulator 7805 on the board for 5 volt power supply. Drawing 6 details the controller unit. K1 , K2 and K3 are flat cable connectors to the other units of the instrument.

The controller board has a relay that turns the boiler's electric heating on and off. d. The user interface The user interface board includes an alpha-numeric LCD module, indication LEDs and keypad.

Figure 7 shows the user interface circuit.

Figure 8 outlines the front panel of the instrument.

There are keys on the panel: MODE, SELECT, UP, DOWN, and RESET.

In the standard operation mode the instrument displays on the LCD the time, the amount of water at a chosen temperature, that temperature and a number representing the currently running program. The bar-graph LED display illustrates graphically what part of the boiler contains water above the chosen temperature. An indication light indicates whether the heating is on or off. 11 I LCD and can be scrolled by the UP and DOWN keys.

An option can be selected by the SELECT key.

Each option when selected leads to another set of options like branches of a tree.

Figure 9 describes a chart of this tree: Options of each branch are connected by arrows .

Option of a branch listed on each line are of the same menu level and can be selected by the UP and DOWN keys.

When an option is selected by the SELECT key the next menu level is opened.

The software detects a key stroke and operates as required; the operation mode is displayed on LCD module. Information about the heater condition, temperature and time are displayed on the LCD module. LEDs are used as bar-graph displays to illustrate the water condition in the boiler.

The system software is real time software in eeprom.

The main program is interrupted by a timer interrupt. The interrupt routine updates the time, reads the pulse count received from the converter and monitors key strokes.

The main program computes the data read by the interrupt routine and takes care of display and user commands.

Figure 1 illustrates a cross section side view of a boiler system containing the temperature sensors installed inside. (2) and an outside cover (3). At the center of the bottom there is a housing for a heater element (4), two water entries for cold water (5) and a solar feed pipe (6). At the top part of the boiler there is a hot water exit pipe (7).

The new parts according to the present invention that are added to said conventional boiler are a probe (8) with a number of temperature sensors (9) installed inside said boiler from the bottom through the solar panel feed pipe. The other new parts connected to the boiler according to the invention ate indicated in the circle at the bottom of the figure and are enlarged and will be described in Figure 3.

Figure 4a illustrates the probe and sensors from above. Figure 4b illustrates the probe and sensors in a side view .

Detailed description of Figure .4fc is as follows: The sensors are at identical distances from one another inside the boiler in the preferred embodiment. The sensors are thermistors, each connected to the converter by a communication wire (10). Said communication wires transmit the sensors' output to the convertor. Said communication wires are inside the probe, in a "dry" area (11) protected made from epoxy material and can be mounted to a hole in the probe wall or by a screwing motion. The communication wire (10) is connected to said seal and sensors from the "dry" area side.

Figure 3 illustrates a cross sectional side view of the probe's mounting (illustrated in a circle in figure 1).

The probe (8) is inserted to the boiler through the solar panel feed pipe (6). The probe walls (11) constitute the border between the "dry" area inside the probe and the "wet" area outside the probe. The solar panel feed pipe wall 1 is connected to a standard T-junction (15). Said T-junction is connected in its horizontal opening (16) to a home water pipe system, and in its bottom vertical opening to the probe housing (17) and the converter (18).

The probe wall (13) pass through the probe housing and are attached at their bottom end by a housing gasket (19) and a fastener gasket (20). A probe fastener (21) beneath said fastener gasket connects the converter housing body (22) to the probe and compresses the gasket.

Inside the converter, the converter circuit board (23) is connected to the sensors' communication wires. Said board is connected to the converter's housing body by screws (24). n n:ii rmmaaom o>onn o>on moD jnpai irPTo A SYSTEM FOR MEASURING AND MONITORING THE QUANTITY AND TEMPERATURE OF HOT WATER IN A BOILER A SYSTEM FOR MEASURING AND MONITORING THE QUANTITY AND TEMPERATURE OF HOT WATER IN A BOILER Field of the Invention The present invention relates to a system for measuring and monitoring the quantity of hot water in a boiler. Said system can provide information in real time about the state of the water in the boiler (temperature in relation to water quantity ) .

Background of the Invention There are many different types of domestic boilers, with and without an attached solar panel. Most of them have an attached electric switch and a thermostat inside.

When one turns on the electricity, a red light lights up. However, this doesn't yet indicate if the electric heating device is on or if the thermostat has turned it off after reaching the temperature for which it was set. When the thermostat turns the electricity (and heating) off the red light is still on.

Israel Patent number 45310 provides some response to this problem. This patent is a simple electric circuit that turns the red light off when the thermostat turns the boiler off. According to the above-mentioned patent the user only knows if there is a maximum quantity of not water (according to the ' ' ' 2 thermostat's setting) but the user cannot know any other important details about the hot water, such as if the solar system can still generate more hot water, or if before the red light goes off he already has enough hot water for his current need.

Another product that improves the use of the home boiler in some way is known as "MADOOD" . This is simply a "SHABBAT CLOCK" attached directly to the electric switch of the boiler, with which one can decide in advance when, and for how long should the additional electric heat work. But the decision is not derived from any analysis of the real situation inside the boiler .

The system according to the present invention overcomes the disadvantages of the above-mentioned known systems.

Fori example, according to the present invention one can know if there is or isn't enough hot water for showering. Furthermore, one can know how many showers can be taken.

Further advantages of the present invention over the prior art are the saving of electricity and time by allowing one to program and order in advance the shower he wants to take later on (e.g. at a time one returns from work, or from the seashore with a known number of persons who will need a warm shower) . 3 Another advantage of the present invention is the ability to prevent the water in cold winter nights from freezing and bursting the water pipes in the solar heaters.

Brief Description of the Invention The present invention relates to a system for monitoring and measuring the quantity and temperature of hot water in a boiler comprising a plurality of temperature sensors installed inside a boiler; a converter that converts said sensors output to pulses or to another binary code readable by a controller capable of counting or decoding said converter output; and having a relay that turns the boilers electric heating on and off; and a user interface unit connected to said controller.

Detailed Description of the Invention The present invention will be better understood, and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the drawings herein appended.

Figure 1 is a block diagram illustrating the main components of the system.

Figure 2 illustrates the probe in the boiler.

Figure 3 illustrates the fitting of the probe to the boiler. Figure 4a illustrates the probe a i sensors from the above. 4 Figure 4b illustrates the probe and sensors in a side view.

Figure 5 shows the electrical design of the converter.

Figure 6 details the controller unit.

Figure 7 shows the user interface circuit.

Figure 8 outlines the front panel1 of the instrument.

Figure 9 shows the user interface flow chart.

The system according to the present invention is designed to give its users information and control of their water heating boiler.

The system can display real time information about the condition in the boiler (temperature vs. water quantity).

It can accept and store a number of user programs and execute them while taking into account solar heating and minimizing electricity consumption. (A program is a request of a certain quantity of water, or time of water outflow, in a certain temperature at a certain time).

Programs stored in memory can be displayed and executed according to the user's choice.

The system can calculate and display information such as water and electricity consumption per water outflow (or shower ) .

When the water in the boiler, or in pipes around it, reaches freezing temperature the system can set an alarm, or just start the electric heating in order to prevent the 5 bursting of pipes in and around the boiler and attached solar panel .

FiQure 1 illustrates a block diagram of the system of the present invention comprising the following main components: (a) The probe (1) inserted in the boiler, (b) A converter/ transmitter (2), (c) A controller (3), and (d) User interface (4). a. The probe The probe is a single unit inserted in the boiler either as a retrofit, or in boiler production. It incorporates a number of sensors in order to measure the temperature at a number of points in the boiler.

When the height of the boiler is longer than its horizontal dimension, the probe may be inserted vertically anywhere in the boiler without being affected by horizontal temperature gradients. This is because of the stratification which takes place in a boiler, causing the existence of layers of water whose temperature is dependent on their vertical location only (Figure 2 illustrates the probe in the boiler) .

When the horizontal dimension is larger than its vertical dimension, there may be more of a horizontal gradient due to the distance and accordingly it may be necessary to insert two probes .

The probe consists of a thin tube nearly as long as the inner length (height) of the boiler. For optimal accuracy the 6 sensors protrude from it, and through its inside run the information cable, connecting the sensors to the converter/ transmitter .

The whole assembly is both waterproof and protected from corrosion. It is made of materials which are insensitive to the working temperature range of the boiler.

Internally the probe may be said to consist of two sections, the one being the probe proper, the second being the fitting by means of which it is attached to the boiler.

The fitting provides a sealed point of entry for the information cables into the probe proper. It is designed to enable quick and easy installment by disconnecting the extending water pipe and inserting the fitting by means of standard threaded joints. The probe is sufficiently thin in order not to hamper the water flow. The fitting is shown in Figure 3.

In the most common types of boilers the possible apertures for installment are either the hot water exit pipe or, where a solar panel is attached, the circulation exit pipe.

An additional sensor is installed measuring the cold water temperature for use in the calculation of the warm water outflow (shower time). This sensor may be attached at the cold water pipe (protected) in such a spot as will ascertain a correct measurement of the temperature. It is independent 7 of the probe and rather is attached directly to the convertor/transmitter .

The calculation method is as follows: The temperature between the points of measurement is calculated by the method of linear interpolation. Since the natural stratification of a gradual heating of the water forms a smooth temperature profile according to height, this method does not cause a significant error.

The temperature at the boiler edges is approximated according to a given mathematic formula.

An additional sensor measures the temperature of the cold water added to the expected output of hot water (Tc).

The desired water temperature is defined externally by the user (Tr) .

The calculation of the water volume in the desired temperature (Tr) is attained according to the formula: Where : x is in the direction of the boiler height T is the temperature at every x according to the interpolation formula.

A is the horizontal area of a cross section of the boiler.

The time of hot water outflow is calculated according to: t = Vtr s 8 Where: s is the nominal out flow of the respective tap.

In case of a need for an additional electric heating to obtain the desired time of use of hot water, the calculation is: 1 ) Vr according to the desired time of hot water outflow 2) Va = Vr - V(Tr) 3) CP * (Tr - Tc)* Va*p W Where : th is the time of the use of electricity W is capacity of the electric heater Cp is the water specific temperature P is the water density.

In this design we use thermistors, but different types of sensors such as thermocouple etc. can be used with little changes in the electronics. b. The Converter The convertor converts the sensors output (resistance) to pulses which can be counted by the controller.

Figure 5 shows the electrical design of the converter - U1 is an oscillator generating a pulse every 2 seconds; these pulses are counted by 3 bit counter U2 and used to select a channel of the analog switch U3.

U4 is a monostable multivibrator which generates a pulse relative in duration to external resistor and capacitor, the external resistor is a thermistor selected by U3 and thus the 9 pulse width is relative to the temperature measured by this thermistor, U4 is triggered by the U1 pulses.

U5 is an oscillator generating square wave of 50 kHz, the pulses of U5 are ANDed logically with the pulse from U4, the output of the AND gate U6 is a number of pulses relative to the temperature measured by the currently selected thermistor.

Transistor Q1 is used to drive a wire to transmit the pulses from the converter located near the boiler to the controller located in the users home.

The full array of cables, both the power lead and the information cable connecting between the convertor/transmitter and the controller is pulled through the existing duct, in use for the power cable. 10 The controller is then inserted where the power switch originally used to be. c. The Controller The controller unit is a Single Board Computer (SBC) such as Intel's 80C31 microcontroller. The board includes an eeprom chip (27C64) that contains the software. There is a power regulator 7805 on the board for 5 volt power supply. Drawing 6 details the controller unit. K1. , K2 and K3 are flat cable connectors to the other units of the instrument.

The controller board has a relay that turns the boiler's electric heating on and off. d. The user interface The user interface board includes an alpha-numeric LCD module, indication LEDs and keypad.

Figure 7 shows the user interface circuit.

Figure 8 outlines the front panel of the instrument.

There are keys on the panel: MODE, SELECT, UP, DOWN, and RESET .

In the standard operation mode the instrument displays on the LCD the time, the amount of water at a chosen temperature, that temperature and a number representing the currently running program. The bar-graph LED display illustrates graphically what part of the boiler contains water above the chosen temperature. An indication light indicates whether the heating is on or off. 11 When the MODE key is pressed the instrument enters a programming mode in which menu options are displayed on the LCD and can be scrolled by the UP and DOWN keys.

An option can be selected by the SELECT key.

Each option when selected leads to another set of options like branches of a tree.

Figure 9 describes a chart of this tree: Options of each branch are connected by arrows .

Option of a branch listed on each line are of the same menu level and can be selected by the UP and DOWN keys .

When an option is selected by the SELECT key the next menu level is opened.

The software detects a key stroke and operates as required; the operation mode is displayed on LCD module. Information about the heater condition, temperature and time are displayed on the LCD module. LEDs are used as bar-graph displays to illustrate the water j condition in the boiler.

The system software is real time software in eeprom.

The main program is interrupted by a timer interrupt. The interrupt routine updates the time, reads the pulse count received from. the converter and monitors key strokes.

The main program computes the data read by the interrupt routine and takes care of display and user commands.

Figure 1 illustrates a cross section side view of a boiler system containing the temperature sensors installed inside. 12 The boiler in said figure is a conventional domestic boiler comprising of an inside cover (1), an isolating layer ( 2 ) and an outside cover ( 3 ) . At the center of the bottom there is a housing for a heater element (4), two water entries for cold water (5) and a solar feed pipe (6). At the top part of the boiler there is a hot water exit pipe (7).

The new parts according to the present invention that are added to said conventional boiler are a probe (8) with a number of temperature sensors (9) installed inside said boiler from the bottom through the solar panel feed pipe. The other new parts connected to the boiler according to the invention are indicated in the circle at the bottom of the figure and are enlarged and will be described in Figure 3.

Figure 4a illustrates the probe and sensors from above. Figure 4b illustrates the probe and sensors in a side view.

Detailed description of Figure .4fr is as follows: The sensors are at identical distances from one another inside the boiler in the preferred embodiment. The sensors are thermistors, each connected to the converter by a communication wire (10). Said communication wires transmit the sensors' output to the convertor. Said communication wires are inside the probe, in a! "dry" area (11) protected '"' 13 from the "wet" area by the probe wall (11a). Every sensor (9) is connected to the probe wall by a seal (12). Said seal is made from epoxy material and can be mounted to a hole in the probe wall or by a screwing motion. The communication wire (10) is connected to said seal and sensors from the "dry" area side .

Figure 3 illustrates a cross sectional side view of the probe's mounting (illustrated in a circle in figure 1).

The probe (8) is inserted to the boiler through the solar panel feed pipe (6). The probe walls (11) constitute the border between the "dry" area ins|ide the probe and the "wet" area outside the probe. The solar panel feed pipe wall , -is connected to a standard T-junction (15). Said T-junction is connected in its horizontal opening (16) to a home water pipe system, and in its bottom vertical opening to the probe housing (17) and the converter (18).

The probe wall (13) pass through the probe housing and are attached at their bottom end by a housing gasket (19) and a fastener gasket (20). A probe fastener (21) beneath said fastener gasket connects the converter housing body (22) to the probe and compresses the gasket.

Inside the converter, the converter circuit board (23) is connected to the sensors' communication wires. Said board is connected to the converter's housing body by screws (24). 14

Claims (9)

1. A system for monitoring and measuring the quantity of hot water and its temperature in a boiler comprising a plurality of temperature sensors installed inside a boiler; a converter that converts said sensors' output to pulses or to another binary code readable by a controller; a controller capable of counting or decoding said converter output and having a relay that turns the boilers electric heating on and off; and a user interface unit connected to said controller. A system according to claim 1 wherein the sensors are at identical distances from one another inside the boiler. A system according to claim 1 wherein the sensors are thermistors . A system according to claim 1 wherein the sensors are thermocouple . A system according to claim 1 wherein the boiler is a solar boiler. A system according to claim 1 wherein the boiler electric boiler. 15 A system according to claim 1 wherein the controller is a Single Board Computer. A system according to claim 7 wherein the Single Board Computer is based on Intel's MCS51 family of microcontrollers . A system according to claims 7 and 8 wherein the Single Board Computer comprising an eeprom chip that contains a real time software burnt in said eeprom; a power regulator for power supply; and cable connectors to the other units of the system. A. system according to claim 1 wherein the user interface board comprises an alpha-numeric LCD module, indication LEDs and keypad. ADVOCATE & PATENT ATTORNEY P. O. B. 3 2081 , Jerusalem 16 Claims : 1. A system for monitoring and measuring the quantity of hot water and its temperature in a boiler comprising a plurality of temperature sensors installed inside a boiler; a converter that converts said sensors' output to pulses or to another binary code readable by a controller; a controller capable of counting or decoding said converter output and having a relay that turns the boilers electric heating on and off; and a user interface unit connected to said controller.

2. A system according to claim 1 wherein the sensors are at identical distances from one another inside the boiler.

3. A system according to claim 1 wherein the sensors are thermistors .

4. A system according to claim 1 wherein the sensors are thermocouple .

5. A system according to claim 1 wherein the boiler is a solar boiler.

6. system according to claim 1 wherein the boiler lectric boiler. 15

7. A system according to claim 1 wherein the controller is a Single Board Computer.

8. A system according to claim 7 wherein the Single Board Computer is based on Intel's MCS51 family of microcontrollers .

9. A system according to claims 7 and 8 wherein the Single Board Computer comprising an eeprom chip that contains a real time software burnt in said eeprom; a power regulator for power supply; and cable connectors to the other units of the system. 11. A system according to claim 1 wherein the user interface board comprises an alpha-numeric LCD module, indication LEDs and keypad. ADVOCATE & PHTENT ATTORNEY P. O. B. 32061, Jerusalem 16