Title:
System for supervision of rooms or buildings
United States Patent 3916405


Abstract:
A system for supervising and monitoring normal or abnormal state in rooms or equipments in a building or buildings in which information signals are delivered from a signal transmitter through lines to a signal receiver, the information signals being discriminated by the signal receiver for supervising and monitoring the rooms or equipments. The system includes a signal transmitter for transmitting information signals of normal or abnormal state in rooms or equipments so as to generate and transmit the signals of different voltage responsive to varied kinds of the information signals. The signal receiver comprises an information detecting means for detecting the information signals of different voltage, a voltage discriminator circuit for discriminating the output from said information detecting means, and an indicator circuit indicating the signals delivered in response to the discriminated information.



Inventors:
GOTANDA MOTOHIRO
Application Number:
05/447363
Publication Date:
10/28/1975
Filing Date:
03/01/1974
Assignee:
GOTANDA; MOTOHIRO
Primary Class:
Other Classes:
340/533, 346/17
International Classes:
G08B25/01; (IPC1-7): H04Q9/00
Field of Search:
340/276,413,409
View Patent Images:
US Patent References:
3821733N/A1974-06-28Reiss
3613092SEQUENCE COUNTING ENCODER MONITOR1971-10-12Schumann



Primary Examiner:
Pitts, Harold I.
Attorney, Agent or Firm:
Larson, Taylor And Hinds
Claims:
What I claim is

1. A system for supervising and monitoring the normal or abnormal state of rooms or equipment in a plurality of buildings wherein information signals are transmitted from a signal transmitter to a receiver, including discriminator means, for supervising and monitoring the rooms or equipment, said system comprising a plurality of signal transmitters for transmitting information signals indicative of the various states monitored within the associated buildings, said transmitters transmitting signals of different voltages corresponding to different abnormal states monitored, and a plurality of signal receivers for receiving said information signals, each said receiver comprising detector means for detecting the voltages of the information signals received by the associated said receiver, and discriminator means for determining the voltage levels of the voltages detected by the detector means, said system further comprising pulse generator means connected to said discriminator means for producing output pulses whose durations vary in accordance with the output of said discriminator means, a scanning circuit driven by said pulse generator means for sequentially scanning the outputs of said detecting means, an indicator means connected to said scanning means for producing a display indicative of the voltage levels of the received information signals as determined by said discriminator means, said indicator means including a plurality of indicator devices which are individually associated with different points in the buildings being monitored and which are energized in sequence by said scanning means for a predetermined time period during normal operating conditions and are energized for a different time period when an abnormal state is sensed, the time period during which said indicator devices are energized when an abnormal state is sensed being a function of the output of said discriminator means, and hence of the particular abnormal state sensed, and being different for different abormal states.

2. A system as claimed in claim 1 wherein said indicator devices comprise indicator lamps.

3. A system as claimed in claim 1 wherein at least one of said receivers includes recording means for recording a change in the condition of the output signal produced by the corresponding signal transmitter, said recording means including logic control means, including an n-bit shift register, for sequentially scanning and adding the information signals received by the receiver, where n is the number of different signals transmitted from the monitored subject, an information discriminator for producing one or the other of first and second binary outputs in accordance with the output of said logic control means, a further, n + 1 bit shift register having an input connected to the output of said information discriminator, a logic circuit having first and second inputs connected respectively to the input and output of said further shift register for determining whether the input and output of said further shift register are different, an electrical circuit means, including a relay, for controlling the operation of a printer responsive to the output of said logic circuit.

4. A system as claimed in claim 1, wherein at least one of said signal transmitters comprises relay coils acting responsive to ON-OFF operation of door switches, an information signal generating means for generating voltages responsive to flowing electrical currents, a plurality of series-connected relay coils and thyristers connected respectively in series to said information signal generating means, a plurality of electrical contacts for sensing a state to be monitored, for rendering said thyristers conducting responsive to the sensing of said abnormal state, and for generating a said information signal responsive to the sensing of said abnormal state, and an electrical circuit having a fire-smoke sensor contact connected through a contact of a relay coil which is operative responsive to the closing of said door switch and is connected in parallel with a fire sensing contact serving as one of a plurality of said electric contacts.

Description:
BACKGROUND OF THE INVENTION

The enormous development of cities has recently increased the number of houses and buildings with each growing much larger in the scale of construction. Each house or building generally contains a large number of rooms or compartments which require frequent and efficient patrol by guards and, accordingly, such patrolling has become a difficult task for the guards for preventing fire or other accidents.

In a larger building where shops, offices and even amusement centers are congregated together each having different business hours, there is the disadvantage that the guards must supervise or patrol all individual rooms at varied hours to meet the need of such shops or business offices.

This has necessitated as many guards as required for the inspection and supervision and these resulted in an unavoidable increase in the number of personnel against the recent trend of automatic management of buildings and reduction of guards.

SUMMARY OF THE INVENTION

Particularly the invention relates to a system for the supervision and monitoring of rooms and equipments in a building or buildings without patrol or inspection by guards, such supervision and monitoring being made electrically and concentrically from one controlling station. Generally, the rooms are supervised of for the locking of doors and prevention of fire and robbery. The equipments usually include means such as elevators and means for water supply and drainage as commonly used for all rooms in a building.

A primary object of the present invention is to provide a system for supervising normal or abnormal state of rooms or equipment in a building without need of guards for the efficient prevention of accident and calamities.

Another object of the invention is to provide a system which can supervise and monitor rooms of a building electrically and without patrol, the absence or presence of personnel and locking or unlocking of doors being successively indicated by the system of the invention.

A futher object of the invention is to provide a system which comprises a signal transmitter for the detection of normal or abnormal state in rooms and a signal receiver to receive the information of such normal or abnormal state to meet the described objects.

Yet another object of the invention is to provide a system which can supervise and monitor a number of buildings singly from a central station by use of the signal transmitter and the signal receiver.

A further object of the invention is to provide a system in which the signal transmitter and the signal receiver each has a simple and economical construction adapted to produce accurate and reliable signals of information.

Still another object of the invention is to provide a system in which the signal transmitter includes a means for detecting even slight smoke or flame of a fire but may not operate for the information of smoke or flame generated from other sources, such as from cigarette or cooking fire.

A further object of the invention is to provide a system which serves particularly for supervision of abnormal state and can record only such abnormal state in rooms or equipments of a building.

According to the invention, there is provided a system for the continuous supervision and monitoring of rooms in a building, which comprises essentially a signal transmitter for transmitting signal of information of normal or abnormal state in rooms or equipments to a signal receiver and a signal receiver to receive and discriminate the signals received from the signal transmitter.

The signal transmitter includes an information signal generator to detect normal or abnormal state in rooms or equipments, discriminate the information signals responsive to different voltages generated from different information sources and transmit the information signals to the signal receiver. The signal receiver includes an information detecting means for receiving the information signal through a signal transmission line, a voltage discriminator circuit to discriminate the output of the information detecting means, and an indicator circuit to indicate the information signal corresponding to the information thus discriminated.

These and other objects and advantages of the present invention may be attained through a variety of mechanical parts and electrical circuits in the system and by operation of such parts and circuits, the detailed description of which will be given below on preferred embodiments with reference to the accompanying drawings. It is noted that any modification or change in the details of the construction or circuits may fall within limit of the invention unless they depart from the spirit and scope of the present invention.

REFERENCE TO THE DRAWINGS

FIG. 1 is a diagrammatic view of an electrical circuit of an embodiment according to the invention;

FIG. 2 is a circuit diagram showing an embodiment of the information signal generator of FIG. 1;

FIG. 3 is a diagrammatic view of a circuit in another embodiment of the invention;

FIG. 4 is a circuit diagram of the embodiment showing the control circuit and indicator circuit of FIG. 3;

FIG. 5 is a circuit diagram of another embodiment showing the information signal generator of FIG. 1; and

FIG. 6 is a circuit diagram of the embodiment showing the construction of a means for recording the information in the signal receiver when a change occurred in the subject of supervision in the transmitter.

DETAILED DESCRIPTION OF THE INVENTION

The system according to the present invention will be described in details below with reference to the drawings.

Referring now to FIG. 1, in which the construction of an embodiment of the invention is shown, numeral 10 denotes a signal transmitter, 20 a signal receiver, and 30 a signal transmission line.

Now assume that a building A has a signal transmitter 10, the building A having a number of rooms, motors for elevators and for water supply and drainage. Preferably each room of the building is provided with various sensors, such as for fire, crime-prevention or robbery. In the door of each room may be provided switches for detecting locking or unlocking of the door. Switches and relays may be set up adequately in the building for detecting abnormal state of motors for elevators and water supply and drainage. These sensors and switches may also sense and detect normal or abnormal state of rooms or equipments.

An information signal generator S, as later described, is provided to issue an information signal a1 for normal state of the whole building, an information signal a2 for opening of doors in a room, an information signal a3 for fire, an information signal a4 for crime-prevention, and an information signal a5 for abnormal state in motors for elevators and water supply and drainage, respectively. These information signals a1 to a5 are thus generated from the above information signal generator S.

The information signals a1 to a5 thus generated from the information signal generator S have respectively different voltages. The difference of such voltages makes it possible to discriminate the information signals a1 to a5 which are given for example in the values of a1 = 5V, a2 = 3V, a3 = 7V, a4 = 8.5V, and a5 = 10V.

The information signal generator S as above described may be a device which can selectively generate the voltages of information signals a1 to a5 as above exemplified. An example of the device is now illustrated with reference to FIG. 2.

In the figure, R1 -R7 denotes resistors, SCR1 -SCR4 thyristors, Dz a zener diode, and SWd a door switch. The door switch SWd, for example, may be provided in the principal door of the building. When a last person retires from the building after work and closes the door SWd, a current flows in the resistor R1 the door switch SWd, the resistor R6 and the resistor R7. Then at an output point P1 in the figure a voltage is applied responsive to the reduced voltage of the resistor R1, that is, the information a1 is generated, when some undesirable person opens a door in the room after all persons retired from the building, a switch for the door will operate, applies a voltage to one gate of the thyrister SCR1, which is then set ON to flow a current to the resistor R2. Accordingly, the current in the resistor R2 and the resistor R1 flows in the resistor R6 and resistor R7. The information signal a2 is generated in the output point P1 indicating the opening of the lock in the door. In the similar manner, the information signals a3 and a4 are obtained in the output point P1 respectively by operation of the sensors for fire, crime-prevention, and robbery.

If it is required to have much more information in the building, the information signal generator S as shown in FIG. 2 may be provided in the rooms or equipments, the output points P1 can then be scanned over in sequence and the obtained information signals for rooms or equipments may be sequentially transmitted to the signal receiver.

The signal transmission line 30 may preferably be in exclusive use or a telephone line may be used instead.

The signal receiver 20 may have an information detector D, a voltage discriminator circuit L and an indicator circuit P as shown on the right in FIG. 1.

The information detector D may include a transistor Tr as emitter-follower to receive an output from both terminal of a load resistor Ro. In the figure, Lo designates an inductance and Co a condenser. Thus, having the emitter-follower provided, it is possible to obtain the voltages through the load resistor Ro without obtaining a current from the transmission line 30 and without lowering the voltages of the information signals a1 - a5 issued from the signal transmitter 10.

The voltage discriminator circuit L is provided with comparators C1 -C5 for discriminating values of voltages in various information signals issued from the information detector D so as to operate a corresponding lamp or alarm bell in the indicator circuit P. Upon the information a3 being issued from the fire sensor, alarm bell BE (not shown) may be sounded or a lamp may be set ON or OFF. In the indicator circuit P as shown, LPdis indicates the disconnection of line (when the carried voltage is in OV, that is, the transmission line is disconnected); LPdc indicates the closing of the lock in the room, LPdo indicates the opening of the door, LPf the happening of fire, LPr the robbery, and LPbo the abnormal state of motors for elevators and water supply and drainage, these lamps being lighted ON or OFF at each occasion.

Thus, according to the invention, the signal transmitter issues a variety of information signals a1 -a5 different from each other in the value of voltage, these informations being applied to the signal receiver over the transmission line, and the signal receiver can receive such information signals through the emitter-follower, so that the information signals a1 -a5 issued from the signal transmitter are transmitted with voltages approximately same as those previously set up in the signal receiver, whereby sure transmission of information signals a1 -a5 is achieved by the transmitter of a very simple construction.

FIG. 3 illustrates another embodiment of a circuit, by which a number of buildings can be supervised and monitored singly from a central station.

In the drawing, A, B . . . N respectively show the buildings, the signals issued from which are transmitted to the signal receiver 20 through their transmission lines 30a, 30b . . . 30n in exclusive use. The signal receiver 20 has at the terminal of its transmission line information detectors Da, Db . . . Dn, respectively. The construction of each information detector of this embodiment is similar to the information detector D of FIG. 1. Outputs of the information detectors Da, Db . . . Dn are respectively applied in respective input terminals of o1 Ga, Gb . . . Gn. Other input terminals of the AND-gate are applied the outputs A', B' . . . N' of a scanning circuit SR having shift resistors and the like. Outputs of the AND-gates as above described are applied in the input terminal of an OR-gate Gol and further output of this OR-gate is connected to a voltage discriminator circuit L. The voltage discriminator circuit L serves to light the lamp LPdis indicating the disconnection of the indicator circuit P and other lamps similarly as the indicator circuit of P shown in FIG. 1 in response to the input information signal, and if required, sounds the alarm bell BE.

A control circuit is denoted by CT, which includes a timing generating circuit T, and an OR-gate Go2, the timing generating circuit T being applied an output from the voltage discriminator circuit L.

A pulse generator PG is provided to issue a pulse of 10 Hz, the output of which sequentially shifts the scanning circuit SR as above described.

LPa, LPb . . . LPn respectively show the indication lamps lighted ON or OFF by the output of the scanning circuit SR indicating the information signal which is issued from whatever buildings of A, B . . . N.

Operation of the circuit of FIG. 3 is now described. Switching ON the power source, the pulse generator PG generates a pulse. The scanning circuit SR shifts by every input pulse to lighten the indication lamps LPa -LPn in sequence and provides an input to the AND-gates Ga -Gn. Thus, output from the buildings A, B . . . N is scanned over by the scanning circuit SR.

Now, in each building, if the interior state is normal, the voltage of the information signal issued from each building has a voltage 5V of the normal information signal a1, which lightens the lamp LPdc in the indication circuit P indicating the normal state of the building. If abnormal state is present, the timing generator circuit T responsive to such abnormal state as described is activated to deenergize the pulse generator PG. For example, if a door for the building B is opened by the undesired person as described above, a voltage signal 3V for the information signal a2 indicating opening of door is applied to deenergize the pulse generator for a second. Then the scanning circuit SR is deenergized just for a second. Consequently, the indication lamp LPb is lighted for a second. The indication lamp LPdo in the indication circuit P operative when the door is opened makes indication similarly for a second. If the information signal shows an emergency indicating such as disconnection of a line, the information signal a3 from fire, the information signal a4 from crime-prevention device, and the information signal a5 for abnormal state in motors for elevators, water supply and drainage, the scanning circuit SR is deenergized for 3 seconds, lighting the corresponding lamps in the indicator circuit P. It is thus possible to know in the transmitter what information was delivered from what buildings A, B . . . N.

FIG. 4 shows a circuit showing an embodiment of a portion of the control circuit CT and the indication circuit P of FIG. 3. In this figure, GN shows an inverter, GA an AND-gate, GO an OR-gate, and DIS, MN, MJC, MJA and MJB relays respectively, the contacts of these relays being respectively shown by dis, mn, njc, mja and mjb. In the timing generator circuit T are provided a one-second timer T1 and a three-second timer T2. MN is a monostable multivibrator used for opening the scanning circuit SR. The voltage discriminator circuit L includes comparators C1 -C5. These comparators are interlocked with one another so that when one of them is activated the other will not operate. The manner of this interlocking operation is same as that conventionally made in the logical circuit. Other circuit construction is similar to that of FIG. 3.

Operation of the circuit of FIG. 4 is now described. When the information signal entering from the OR-gate Go1 has a voltage for the information signal a1 indicating normal state in a room of a building, the comparator C2 is activated and no alarm bell is energized. When such information signal has a voltage 3V for the information indicating the opening of the door by the person as described, the comparator C1 is activated, whereby the one-second timer T1 is acted to deenergize the pulse generator PG of the multivibrator. Accordingly, the scanning circuit SR is deenergized. By action of the comparator C1 is obtained an output in the AND-gate GA. Assume that in this circumstance one output of the AND-gate has been set up. Then, as the AND-gate issues an output, the relay MN is energized. The contact mn is closed to energize the alarm bell BE and simultaneously lights the indicator lamp LPdo. The time of this indication continues a second. When the signal transmission line 30 is disconnected, the output of the comparator C1 turns zero so that an output is generated in the inverter GN to energize the relay DIS. The contact dis is closed to light the indication lamp LPdis energizing the relay AL, its contact al being closed to energize the alarm bell BE.

Also, when the information a3 from the sensor for fire has a signal voltage 7V, the comparator C3 acts to energize the relay MJC and contact mjc. As the indication lamp LPf is lit, the alarm bell BE is energized. At this moment, a 3-second timer T2 is activated through the OR-gate GOa to light the lamp for three seconds and energize the alarm bell.

Similarly, when the information a4 from the crime-prevention source has a signal voltage 8.5V, the comparator C4 is activated. When the information a5 has a signal voltage 10V indicating the abnormal state of motors for elevators and a signal voltage 10V for water supply and drainage, the comparator C5 is activated. These C4 and C5 energize the three-second timer T2, indication lamp LPr and LPbo for 3-seconds issuing an alarm of emergency information. In the figure, RLS denotes a return switch.

The above embodiments are applied to the case where the building having the signal transmitter 10 is located away from the signal receiver 20 for supervising the building. The same also applies to the case where a number of rooms in the same building are supervised and monitored from one station in the building.

The variety of informations a1 -a5 may also be set up in various ways without being limited to the ways as above described and the signal voltages for such informations may be determined as preferred.

FIG. 5 shows another embodiment of the information signal generator S of FIG. 1. In ordinary buildings, smoke or flame are often generated from sources other than fire such as from, cigarette smoking or cooking in the kitchen. The described circuit has been designed to distinguish fire other than issued from cigarettes or cooking in the kitchen and generate an information signal only when a fire occurs by accident.

In the figure, SWd denotes a door switch fixed at the principal door of a room or a building with the switch located aligned with the relay coil DC. The information signal generating section Z includes a serial circuit of resistors Ra and Rb and a Zener diode Dz for generating a constant voltage, in which a voltage of a predetermined value is generated by a current flowing in the circuit issuing an output from a jack JK. A thyrister SCR2 for the information signal a3 is activated by sensing the smoke of accident fire as described above, which is provided serially with a relay coil AC and includes a fire sensing contact m' (for example, in a fire sensor such as heat sensor successively operating irrespective of opening or closing of the door switch SWd) connected between a resistor Rc in the anode of SCR2 and a resistor Rd connected at the terminal to a negative power source -E. In parallel with the fire sensing contact m', there is connected a fire-smoke sensor contact SD (for example, in a smoke or flame sensor which is quite sensitive and operative only when the door switch SWd is closed) through a contact do of the relay coil DC. Further, the anode of the thyrister SCR2 is connected in series with the information signal generating section Z through a reset switch RLS. SCR4 designates a thyrister for the information a5 which indicates abnormalities in the motor operation for elevators and water supply and drainage, the thyrister SCR4 being connected in series with the relay coil CC. Between the gate of SCR2 and the negative power source -E are connected in series the resistor Re and the contact SB which opens when the water supply and drainage are in trouble. The above described thyrister SCR4 is connected through the contact a' of the relay coil AC and the contact b' of later described relay coil BC in series to the information signal generating section Z. Rf denotes a resistor serially connected to the contact SB. SCR3 is the thyrister for the information signal a4 issued from the crime-prevention means. The thyrister SCR3 is serially connected to a relay coil BC and has a contact CB including a resistor Rg and a breaking conductor in series between the gate of the thyrister and the negative power source -E. The breaking conductor is made of a thin breakable glass, on which a metal film is coated by deposition or adhered by spattering. The breaking conductor may be attached to a glass window or an easily breakable place to become non-conducting when a person may break through the window.

The anode of the thyrister SCR3 is connected in series to the information signal generating section Z through the contact a" of the relay coil AC and the contact d1 of the relay coil DC. Rh indicates the resistor serially connected to the contact CB. In the figure, R denotes the resistors; C the condensers; and D the diodes.

Operation of the circuit in the same figure is now illustrated. The door is closed and then the door switch SWd is closed to activate the relay coil DC. If abnormal state is not present in the building, a current from the resistors Rf and Rh flows in the information signal generating section Z producing the information signal a1 indicative of the normal voltage 5V in the information signal generating section Z, which information is issued from the jack JK.

When the door switch SWd is opened, the relay coil DC returns to open the contacts do and d1. A current flows from the resistor Rf to the information signal generating section Z, where the information signal a2 indicative of opening of the door lock in voltage 3V is generated. When the door switch SWd or the contact do is closed and the fire sensing contact m' or fire-smoke sensor contact SD is closed, the thyrister SCR2 is operated to activate the relay coil AC, whereby a current through the thyrister SCR2 and a current through the resistors Rf and Rh flows into the information signal generating section Z, in which the information a3 to sense the fire corresponding to a voltage 7V is generated.

As the contact SB opens due to troubles in the water supply and drainage or in the elevator, the thyrister SCR4 is operated to activate the relay coil CC, whereby a current through the thyrister SCR4 and a current through the resistor Rf flow into the information signal generating section Z to issue an information signal a5 in voltage 10V. If a person breaks into a door of a house, the contact CB including a breaking conductor is first broken. Accordingly, the thyrister SCR3 is operated to activate the relay coil BC. A current through the thyrister SCR3 and a current through the resistor Rh flow into the information signal generating section Z, where the information signal a4 is generated issued from the crime-prevention means indicative of a voltage 8.5.V.

The fire-smoke sensor contact SD making the thyrister SCR2 conducting is not operated if the door switch SWd is opened, since the relay coil DC and accordingly the contact do are opened, whereby the fire-smoke sensor contact SD is not operated regardless of presence of cigarette or cooking smoke or flame inside the room. If a fire occurs, however, the fire sensing contact m' will be operated to activate the thyrister SCR2.

Thus, the fire sensing contact m' serving as one of the contacts for making the thyrister SCR2 conducting is connected through the contact do of the relay coil DC to act by closing of the door switch SWd.

When a fire occurs upon the door switch SWd is opened, i.e., when a person is present in the room, or upon the door switch SWd being closed, the fire sensing contact m' operates to indicate the fire. This means that the fire sensing contact m' constantly performs supervision.

On the other hand, the fire-smoke sensor contact SD including the very sensitive smoke and flame sensor is not activated when the door switch SWd is opened, i.e., when a person is present in the room, but when the door switch SWd is closed, i.e., when a person is absent or in bed, the fire-smoke sensor contact SD senses even slight smoke or flame causing a fire and indicates the fire.

The very sensitive and excellent fire-smoke sensor nowadays instantly operates in response to the occurrence such as of smoke from cigarette and often it leads to issuance of an erroneous information of a fire. Assume that a person in a room may have a fire, he is the first to inform the occurrence of the emergency, that is, he may serve as an excellent sensor so that, during presence of that person, such very sensitive fire-smoke sensor may be dispensed with. The sensor then may be operated only when a person is not present in the room or is in bed to activate the fire-smoke sensor contact SD so as to sense the fire earlier without issuing the erroneous information.

So that, when a fire occurs while a person is present, i.e., when the door switch SWd is opened, the fire may be early informed to the supervisor, an emergency button switch may be provided in the circuit of fire information. Such emergency button switch SWa may be provided in parallel with the fire sensing contact m'. Pushing the button switch SWa, the fire may be immediately informed to the outside even when the door switch SWd is opened.

In FIG. 6 is shown an embodiment of a circuit, by which the signal receiver can record the information delivered from the signal transmitter when an abnormal state occurs. In the circuit, SR1 is a shift register which may be provided in the number of n-bits if the material to be supervised by the signal transmitter, e.g., the subjects to be detected from the information signals a1 -a5 are of the n number. MV denotes a multivibrator which shifts the shift register SR1 and simultaneously steps up the counter Cu. Outputs of the shift register SR1 are connected that they should serve as inputs for AND-gates G1 . . . Gn in the n number. The shift register SR1 is connected to the indicators P1 . . . Pn for luminous diodes indicative of the action of the shift register SR1. A transmission line 30 is provided to apply various information signals S1 . . . Sn from the subjects of supervision in the n number same as the other inputs for the AND-gates G1 . . . Gn. Output of each AND-gate G1 . . . Gn is applied in the OR-gate GT. LD denotes an information discriminator for detecting what information has the output from the OR-gate GT. For example, the information signals S1 . . . Sn are applied as inputs to discriminate the difference in the voltage. The information discriminator LD is then provided with many comparators to discriminate the difference in the voltage. As the result, a normal signal is issued as an output of 0 and an abnormal signal as an output of 1.

The shift register SR2 issues one input and one output in n + 1 bits for the subjects in the n number as described. The shift register SR2 is also shifted by the multivibrator MV. By X is denoted a logical circuit which includes inverters GN1, GN2 and AND-gates GA1, GA2. AM1, AM2 are amplifiers, AY, BY relays, and PT a printer. Contacts of relays AY, BY are shown by ay and by, respectively, which contacts cause the input information signals S1 . . . Sn to be printed. Output Cout of the counter Cu is also printed at the same time. The input information signal is printed indicating from which subject of supervision it is issued.

Operation of the preceding circuit is described below.

Inputs of the information signals S1 . . . Sn pass through the gates G1 . . . Gn in sequence. If the information discriminator LD issues a signal 1, it indicates that the state is abnormal and if normal, it issues a 0 signal. In this manner, the signals are registered in sequence in the shift register SR2.

Therefore, the input applied in the input side of the shift register SR2 and the output issued from the output side are signals of the same bit in the shift register SR1. Thus, the input signal and the output signal of the shift register SR2 are compared. The difference between these signals may be printed by the printer PT in printed signals for activating the relays AY and BY.

Assume that the signal from the information discriminator LD is 1. If the same signal in the preceding cycle is also 1, the input of the shift register SR2 may be 1 and the output may be 1 so that the output of the inverter GN1 may be 0, that is, the output of the AND-gate may be 0. Since the output of the inverter GN2 is 0, the output of the AND-gate GA2 may be 0. Then, the amplifiers AM1, AM2 will not operate. The relays AY, BY will not operate also so that the printing is not made.

When the circumstance is changed and the signal from the information discriminator LD turns 0, then the input of the shift register resistor SR2 turns 0 and the output turns 1, so that the output of the inverter GN2 turns 1 and the output of the AND-gate GA2 turns 1. The amplifier AM2 will operate to activate the relay BY issuing a printed signal to the printer PT. When the circumstance changes and the output of AND-gate GA2 turns 1 and the input of the shift register SR2 turns 1 with the output turned 0, the output of the inverter GN1 turns 1 and the output of the AND-gate GA1 turns 1. The amplifier AM will operate to activate the relay AY issuing a printed signal to the printer PT.

In this embodiment, the output of the information discriminator LD is 0 when the input has a normal signal and 1 when it has an abnormal signal. This is true with the reverse case.

The embodiment has the following advantage. According to the system as referred to in FIG. 1, the guard or supervisor may reach a place where abnormal state occurs in the subjects to be supervised, he can record the abnormal state at the same time. Delivery of long recording paper continuously to the signal receiver should cost very high as well as it has a disadvantage of consuming much time for analyzing the record so that it is not practical. The invention of this embodiment enables the recording of any change in the subject and the most efficient printing of the record. The invention is particularly effective in the case where accurrence of abnormal state is not much probable for supervising and monitoring the rooms or buildings.