JP3763494B2 - Centralized display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a display device that centrally manages detection states by detection means provided at a plurality of locations, and particularly includes a switch contact that is turned on and off in conjunction with a detection operation in the detection means, and a current is supplied from the display device side to the switch contact. It is related with what detects an on-off state.
[0002]
[Prior art]
Conventionally, various types of cooling or heating devices have been provided with switch-type temperature detection means for monitoring abnormalities in the internal temperature, while currents are separately supplied from the alarm central display device side to the switch contacts of the temperature detection means. In general, a switch alarm is detected by detecting an on / off state of the switch contact, that is, a temperature abnormality, and displaying a predetermined alarm.
[0003]
By the way, the above-described temperature detecting means still often has a bimetallic temperature sensor having a mechanical contact in consideration of its durability and price. However, in this mechanical contact, there is a high possibility that the contact resistance of the contact will increase due to long-term use, and the current supplied from the centralized display device side is a weak current of 1 to 10 mA or less, There is a strong possibility that the temperature abnormality determination operation by the display device malfunctions due to instability of contact resistance.
[0004]
Therefore, conventionally, by utilizing the fact that the current capacity of the mechanical contact is relatively large, the influence of contact resistance is avoided by initializing the current value so that a relatively large current of 100 mA or more flows. I have been.
[0005]
On the other hand, along with the computerization of the control circuit, the temperature sensor is increasingly used as a thermistor and a semiconductor switch that is turned on and off by its physical change. However, in this case, the contact resistance does not fluctuate contrary to the above, and if a large current is passed for a long time, the switch itself may be damaged. The limit is small.
[0006]
[Problems to be solved by the invention]
However, even if a large current is required for the detection of the mechanical contact described above, for example, in order to flow a current of 100 mA by applying a voltage of 12 V, a 120 Ω resistance load is required, and the resistance is 2 W or more. Capacity is required. Further, there are few problems when the number of detection means is small, but when the number of detection means increases to several tens or more, an increase in the installation area of the resistor or the manufacturing cost cannot be ignored. In particular, in a centralized display device that issues an alarm after detecting that an abnormal state has continued for a predetermined time instead of a short period of time, the effect of heat generation on the resistance load is significant.
[0007]
On the other hand, in the case where the detection means is provided with a semiconductor switch, the above-described influence of heat generation is rarely a problem. However, whether or not a centralized display device is provided as part of a completely new system, it is common to provide a centralized display device in addition to existing equipment. Since there is a possibility that a switch of a formula may coexist, it has been considered that not only a detection circuit designed with the same electrical specification but also a unified detection operation is impossible.
[0008]
The present invention solves the above problems all at once, and can be applied regardless of the type of switch contact provided in the detection means prepared by the user of the centralized display device, and the power capacity of the load resistance is minimized. However, an object of the present invention is to provide a centralized display device capable of performing stable detection and determination operations with few malfunctions.
[0009]
[Means for Solving the Problems]
The centralized display device 16 according to the present invention includes a plurality of detection means 12 having switch contacts 10 that are turned on or off in conjunction with a predetermined detection operation, as schematically shown in FIG. It is connected to the detection unit 14, detects the current flowing through each switch contact 10 in the detection unit 14, and performs display corresponding to the on / off state of each switch contact 10.
[0010]
In the present invention, the detection of the on / off state of the contact 10 is intermittently performed at predetermined time intervals, and the current flowing through the contact 10 when the switch contact 10 is turned on is predicted to be connected. While the switch contact 10 is set to a value as large as possible, the time during which a current flows through the switch contact 10 is set to a value as short as possible to enable the above-described detection operation.
[0011]
While the above-described detection means 12 is a thermo switch that is turned on when a predetermined temperature is exceeded, the on-state display of the detection means 12 is after it has been determined that the on-state has continued for a predetermined time. Can be configured to be made.
[0012]
【The invention's effect】
As described above, the present invention is configured so that the current flowing through the switch contact 10 can be set as large as possible. Therefore, the type of the switch contact 10 used is not limited, and a stable detection operation with few malfunctions can be performed. On the other hand, since the current flowing time through the switch contact 10 is suppressed to the minimum necessary for detection, it is possible to select a load resistor with a small power capacity as a load resistance provided on the display device side, thereby reducing the circuit board size and the manufacturing cost. Can be planned.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In the following, the present invention provides a predetermined alarm display when it is detected that the internal temperature of the cooling device has risen above the set temperature via a plurality of sets of temperature detection means 12 provided in the detection unit 14 of the cooling device. Although it demonstrates based on the example implemented in the centralized display apparatus 16 to perform, while not only this but the switch means 10 provided with the switch contact 10 in which a closed state reverses in conjunction with predetermined | prescribed detection operation | movement in the detection means 12 side, It goes without saying that the present invention can be implemented in substantially the same manner with respect to various types of display devices that perform a predetermined display by determining the closed state of the switch contact 10 by passing a current.
[0014]
The centralized display device 16 according to the present invention has a driving voltage V1 with respect to the switch contact 10 constituting a plurality of sets of detection means 12 provided in the detection unit 14, as schematically shown in FIG. , An energization timing detection unit 20 that detects when the switch contact 10 is energized by the energization unit 18, an alarm display unit 22 that performs display corresponding to the detected energization state, and an energization timing detection unit 20 And a selection unit 24 that enables selection and control of the operation timing of the alarm display unit 22, a central control unit 26 that controls the operation timing of each unit described above, and a manual setting unit 28 that enables various setting operations manually. Composed.
[0015]
The central control unit 26 is composed of, for example, a one-chip microcomputer, and includes a plurality of input / output ports, and its operation is controlled by a program that performs an operation according to a flowchart described later. Of course, if the same operation is performed, the specific configuration can be changed as appropriate.
[0016]
The energization section 18 is controlled by the above-described central control section 26, and one set is provided for each switch contact 10 as specifically shown in FIG. The light emitting circuit 30 is connected to all the light emitting circuits 30 in parallel, and includes a switching circuit 32 that regulates the application time of the drive voltage V1 of DC 12V, for example.
[0017]
The switching circuit 32 includes two transistor switches 34 and 34a connected in Darlington, and the emitter and collector terminals are turned on corresponding to the period when the “H” signal output from the central control unit 26 is input to the base terminal. A predetermined drive voltage V1 is applied to all the light emitting circuits 30.
[0018]
The light emitting circuit 30 has a light emitting element 40 of a photocoupler 38 interposed between a connection terminal 36 to which both ends of the switch contact 10 are detachably connected and an output end of the switching circuit 32. In the present embodiment, a resistor 42 is provided in series with the light emitting element 40 to limit the current flowing through the light emitting element 40, while a current bypass resistor 44 is provided in parallel with the switch contact 10. The flowing current is made larger than the minimum value necessary for detection.
[0019]
Although the current flowing through the switch contact 10 is set to be at least 100 mA, the switch contact 10 may be used with a relatively small current capacity such as a semiconductor switch, and the current range does not cause malfunction. Of course, the current value is set and changed as appropriate. Further, diodes 46 and 48 connected in the reverse direction and a peak voltage limiting element 50 are provided so that the influence of the counter electromotive force generated when turning on / off the large current does not reach the light emitting element 40 and the switching circuit 32 side. .
[0020]
As described above, when the switching circuit 32 is turned on while the switch contact 10 is on, the light emitting element 40 in the corresponding light emitting circuit 30 is energized, and the light emitting element 40 performs a light emitting operation. On the other hand, the light receiving element 52 that receives the light emitted from the light emitting element 40 of the photocoupler 38 is disposed on the energization timing detection unit 20 side shown in FIG. 3 and notifies the central control unit 26 of the ON state of the switch contact 10.
[0021]
The energization timing detection unit 20 connects one end of the light receiving element 52 constituting the photocoupler 38 to the data input terminal of the central control unit 26 via the backflow preventing diode 54 and the inverter 56, while The end can be grounded via the selector 24.
[0022]
Therefore, the pull-up voltage V2 is normally inverted by the inverter 56 and the “L” signal is input to the central control unit 26. However, when light enters the light receiving element 52 from the light emitting element 40, the light receiving element 52 Is turned on, and the data input to the central control unit 26 becomes “H” by grounding the pull-up voltage V2 to notify the central control unit 26 that the switch contact 10 is turned on.
[0023]
The energization timing detection unit 20 includes the number of light receiving elements 52 (16 in this embodiment) corresponding to the maximum number of switch contacts 10 that may be connected. However, in reality, the number of input / output ports that can be used is limited to a small number.
[0024]
Therefore, in this embodiment, row lines 58 are provided for two data output ports and eight data input ports, and 16 column lines 60 are provided orthogonal to the row lines 58. Furthermore, while providing an input / output terminal for data at the intersection of the row and column lines 58 and 60, the selection unit 24 controlled by 4-bit data can alternatively select 16 column lines 60. Thus, input / output control of a maximum of 160 different data can be performed by 14 input / output ports.
[0025]
The selection unit 24 includes a conversion circuit 62 that individually outputs control signals from 16 output terminals corresponding to the 4-bit binary numbers output from the central control unit 26, and 16 control terminals. The control circuit 64 includes a ground control circuit 64 that can individually ground each control terminal by inputting a control signal to be sent.
[0026]
Further, the 16 selection lines 66 extending from the 16 control terminals provided in the ground control circuit 64 are alternatively connected to the 16 column lines 60 described above. Accordingly, the column line 60 not selected by the selection unit 24 is maintained in a high impedance state, and the light receiving element 52 provided at the intersection with the corresponding row line 58 is forcibly maintained in an off state and does not operate.
[0027]
However, when the column line 60 specified via the selection unit 24 is grounded, the intersection position with the grounded column line 60 becomes active, and this corresponds to the light receiving element 52 being turned on at that time. The row line 58 is grounded, and its state is inverted by the inverter 56 and sends an “H” signal to the central control unit 26 to centrally control that a specific light receiving element 52 and thus a specific switch contact 10 is turned on. The unit 26 is informed.
[0028]
The alarm display unit 22 is composed of first and second light emitting display circuits 68 and 70 that are lit when the switch contact 10 is turned on and display by light, and a sound generation display circuit 72 that generates a buzzer sound and displays the sound. The
[0029]
Here, the first light-emitting display circuit 68 is provided in, for example, a housing for housing the centralized display device 16 and generates a preliminary alarm by blinking immediately after the switch contact 10 is turned on. Reference numeral 70 is on the outer surface of the housing, and lights up after confirming that the ON state of the switch contact 10 has been maintained for a set time, thereby indicating that a full alarm state has been entered.
[0030]
Each of the first and second light emitting display circuits 68 and 70 is a light emitting diode 74 and is provided with 16 each corresponding to 16 switch contacts 10 and is connected to Darlington from two output terminals in the central control unit 26. The two row lines 58 are extended through the switching transistors 76 and the light emitting diodes 74 are connected to 32 intersections formed between the 16 column lines 60.
[0031]
Therefore, the central control unit 26 turns on the switching transistor 76 to select the row line 58 to be energized, while the selection unit 24 grounds a specific column line 60, thereby selecting the selected row and column line 60. The voltage V3 is applied to the specific light emitting diode 74 provided on the intersection via the switching transistor 76, and the light is selectively turned on.
[0032]
The manual setting unit 28 sets a delay time from when the switch contact 10 is turned on and the first light emitting display circuit 68 is activated until the alarm display in the second light emitting display circuit 70 is started. By displaying the delay time in four digits in binary in the ON / OFF state of the intersection by the switch group 78 including four ON / OFF switches provided between the intersections of four row lines 58 and one column line 60, for example, Multiple time settings can be made manually every 0 to 10 minutes. This switch group 78 can be set individually for each switch contact 10 by providing one set for each of the 16 switch contacts 10.
[0033]
The present invention has the above-described configuration, and is further characterized in that detection and display operations are performed in accordance with the flowchart shown in FIG. That is, when the apparatus is started in step 1, after the initial setting is made in step 2, the display processing process in step 4 is normally repeated. However, if a timer interrupts at a predetermined time interval of 400 milliseconds in step 3, for example, the detection processing process starting from step 5 is entered, but the process of returning to the display processing process of step 4 is repeated as soon as the series of processing ends.
[0034]
When entering the detection processing step, the switching circuit 32 is turned on in step 5 and the drive voltage is applied to all the light emitting circuits 30. Then, the detection processing from step 6 is performed, and immediately after the detection processing is completed, the process proceeds to step ST11. By stopping the drive voltage, the energization time for the switch contact 10 is set to the minimum necessary.
[0035]
Here, the RAM in the central control unit 26 is provided with flags corresponding to the 32 light-emitting diodes 74 constituting the first and second light-emitting display circuits 68 and 70, and corresponds to the 16 switch contacts 10. The data area for recording the ON duration time is individually provided.
[0036]
Therefore, if it is determined in step 6 that all of the switch contacts 10 are in the OFF state, the flag for specifying the light emitting diode 74 to be subjected to the light emission process and the elapsed time data are returned to the initial state in step 7, and then step 4 is performed. Return to the display processing operation.
[0037]
However, if at least one ON state of the switch contact 10 is determined in step 6, only the corresponding flag on the first light emitting display circuit 68 side is set in step 8, and the elapsed time data is examined and set in step 9. If it is determined that the switch contact 10 exceeds the time, a corresponding flag on the second light emitting display circuit 70 side is set in step 10.
[0038]
On the other hand, in the display processing step of Step 4, the light emitting diode 74 in the first light emitting display circuit 68 corresponding to the flag set in the above detection step is blinked, while the response in the second light emitting display circuit 70 is performed. The light emitting diode 74 is turned on, and the sound generation display circuit 72 is activated to activate the signal, so that the switch contact 10 that is currently turned on and possibly alarmed, and the alarm is already generated when the set time elapses. It is displayed by sound and light while distinguishing from the switch contact 10 that has reached the state.
[0039]
In addition, instead of performing the energization operation on the switch contacts 10 by the energization unit 18 as described above on all the switch contacts 10, the energization and detection operations can be performed separately for each of the switch contacts or a plurality of switch contacts. . On the other hand, the operation performed in a time-division manner via the selection unit 24 can be performed at or near a state by using the central control unit 26 having a sufficiently large number of input / output ports. Is also possible.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically showing an overall configuration of the present invention.
FIG. 2 is an electric circuit diagram showing a specific configuration of an energization unit.
FIG. 3 is an electric circuit diagram showing a specific configuration of an energization timing detection unit, an alarm display unit, and a selection unit.
FIG. 4 is a flowchart showing an example of a control procedure by the central control unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Switch contact 12 Detection means 14 Detection part 16 Centralized display device 18 Current supply part 20 Current supply time detection part 22 Alarm display part 24 Selection part 26 Central control part 28 Manual setting part 30 Light emission circuit 32 Switching circuit 34 Transistor switch 36 Connection terminal 38 Photo Coupler 40 Light emitting element 52 Light receiving element 56 Inverter 58 Row line 60 Column line 62 Conversion circuit 64 Ground control circuit 66 Selection line 68 First light emitting display circuit 70 Second light emitting display circuit 72 Sound emitting display circuit 74 Light emitting diode 76 Switching transistor 78 Switch group

Claims (2)

It is connected to a detection section (14) having a plurality of detection means (12) having a switch contact (10) that is turned on or off in conjunction with a predetermined detection operation, and each switch contact (10) in the detection section (14). ) To detect the current flowing through the switch contacts (10) and perform display corresponding to the on / off state of each switch contact (10),
While the on / off state of the switch contact (10) described above is intermittently detected at predetermined time intervals,
While setting the current flowing through the contact (10) when the switch contact (10) is turned on to a value as large as allowed by the switch contact (10) expected to be connected,
A centralized display device characterized in that the time during which a current flows through the switch contact (10) is set to a value as short as possible to enable the above-described detection operation. The switch contact (10) described above is a thermoswitch that is turned on or off when a set temperature is exceeded,
2. The centralized display device according to claim 1, wherein the on-state display of the switch contact (10) is performed after it is determined that the on-state has continued for a predetermined time.

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