JPH11260213A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid abnormal operations due to the failure of a power supply circuit, without multiplying the built-in power supply circuit by providing a diagnostic part for diagnosing a failure of a first supply part based on output voltage of the first power supply part and a second power supply part being s plied to the diagnostic section, and by turning off output of operation result signals from an electronic apparatus, when the diagnostic part diagnoses a failure. SOLUTION: A safety area sensor, when light emitting from a projector 30 is not detected by a light-receiving device 40, considers that a human body intrudes into a press machine, turns off control output of the sensor, and forcibly stops the operation of the press machine. A second power supply 2 supplies a voltage directly converted from an external power supply only to a power supply voltage monitoring part 3. When the power supply voltage monitoring part 3 diagnoses failure of a main power supply 1, control outputs from output circuits 12, 22 are turned off. Thus, error output due to the failure of the main power supply 1 is avoided, without multiplying the main power supply 1, and reliability of this safety area sensor is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electronic equipment,
In particular, the present invention relates to an electronic device having a power supply circuit failure detection function.

[0002]

BACKGROUND OF THE INVENTION Multiplexing techniques, such as dual systems, are often used for safety components, such as photoelectric sensors used for safety applications. This is because even if an internal electronic component fails due to deterioration or the like, the failure is detected and the output of the sensor is operated to a safe side.

[0003] Multiplexing of power supply circuits is a very important part of this. Because if the power supply circuit breaks down,
This is because high voltage of the internal circuit of the photoelectric sensor is supplied, and most of the internal circuit may be broken.
In that case, it is meaningless even if the internal circuits are multiplexed. Therefore, when multiplexing the internal circuits, the power supply circuits also need to be multiplexed.

[0004] However, multiplexing the power supply circuits not only increases the size of the device, but also causes variations in the operating voltages in the device because the output of each power supply circuit varies. This hinders transmission and reception of signals between multiplexed channels. For example, the operating power supply voltage of 0.
9 to 1.1 times the H input (4.5 V when the operating voltage is 5 V)
~ 5.5V) for the CPU input port,
When the power supply voltage is 4.5 V, the H input voltage is 4.5 V ×
(0.9-1.1) = 4.05V-4.95V,
If the operating voltage of the other channel exceeds 4.95 V, it exceeds the rating and may be destroyed, so that the input of H level cannot be made.

In order to solve the above-mentioned problem, if a solution is adopted in which a resistor is inserted into a signal line extending between channels to eliminate the influence of a voltage difference, a port input capacitance and a resistor of a CPU are required. Since the integration circuit is used, the pulse width cannot be reduced, and the problem that the communication speed is reduced remains.

In addition, when the solution of adjusting the output voltage of the power supply circuit at the time of assembling is employed, the number of assembling steps increases, or if the output voltage fluctuates for some reason after the adjustment (for example, when the output voltage is used for adjustment). Output voltage fluctuations caused by the failure of the variable resistor, and the problem that signals of the correct voltage level cannot be transmitted and received remains.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic apparatus capable of avoiding an abnormal operation due to a failure of a power supply circuit without multiplexing a built-in power supply circuit.

[0008]

According to the present invention, an electronic apparatus operates by receiving a drive voltage from an external power supply and outputs an operation result signal, and receives a voltage from the external power supply. A first power supply unit for outputting to and supplying to each unit of the electronic device, a diagnosis unit for diagnosing a failure of the first power supply unit based on an output voltage level of the first power supply unit, and a diagnosis unit for inputting a voltage from an external power supply And a second power supply unit different from the first power supply unit for supplying power to the power supply unit. Then, when the diagnosis unit diagnoses the failure,
The electronic device is configured to turn off the output of the operation result signal.

Since the electronic device according to the first aspect is configured as described above, when the failure of the first power supply unit is diagnosed by the diagnosis unit, the output of the operation result signal of the electronic device is turned off. . Therefore, the first power supply circuit of the electronic device
The presence or absence of a failure in the power supply unit is monitored and the first power supply unit is not multiplexed, and the output of a malfunction result signal to the dangerous side due to the failure of the first power supply unit is avoided, and the safety of the electronic device is reduced. improves.

[0010] Even if the internal parts are multiplexed, the voltage used in the electronic device is supplied by the first power supply, which is a single main power supply. , No potential difference occurs, and the accuracy of the transmission / reception operation between channels is maintained.

According to a second aspect of the present invention, the electronic device according to the first aspect further includes a monitoring unit that monitors whether a function of the diagnosis unit operates normally. This monitoring unit has a function of the diagnosis unit. When detecting that the electronic device does not operate normally, the output of the operation result signal by the electronic device is turned off.

According to the electronic device of the second aspect, the function of the diagnosis unit is monitored by the monitoring unit, and when the normal operation is not performed, the output of the operation result signal is forcibly turned off.
Therefore, when the accuracy of the diagnostic function of the first power supply unit is not guaranteed, the monitoring device promptly shifts the electronic device to a state in which the malfunction result signal is not output to the dangerous side. Safety is improved.

According to a third aspect of the present invention, in the electronic device according to the second aspect, a circuit unit for operating and outputting an operation result signal is duplicated, and a diagnosis unit is provided by a first power supply unit. An upper limit detection unit that turns off the output of the operation result signal by one of the circuit units in response to the voltage supplied to each of the circuit units exceeding the upper limit value, and an upper limit detection unit that is supplied to each of the circuit units by the first power supply unit. A lower limit detection unit that turns off the output of the operation result signal by the other electric circuit unit in response to the voltage that has exceeded the lower limit value, and the monitoring unit includes at least one of the upper limit detection unit and the lower limit detection unit. When it is detected that the circuit unit does not operate normally, the output of the operation result signal by each of the circuit units is turned off.

According to the electronic device of the third aspect, the first
When the upper or lower detection unit of the diagnostic unit that diagnoses that the supply voltage to each circuit unit by the power supply unit exceeds the upper or lower limit value does not operate normally, the monitoring unit multiplexes the electronic device. Since the output of the operation result signal by each circuit unit is forcibly turned off, not only the failure of the first power supply unit but also the failure of the diagnosis unit that monitors the normal operation of the first power supply unit causes a failure in the electronic device. Since the output of the operation result signal from each of the multiplexed circuit units is turned off, it is possible to reliably prevent a decrease in safety due to the output of the malfunction operation result signal to the dangerous side.

Further, since the voltage used in the electronic device is supplied by the single first power supply unit, even if the circuit units are multiplexed, a potential difference occurs between the circuit units (channels). Therefore, signal transmission and reception between the respective circuit units can be performed normally.

According to a fourth aspect of the present invention, the monitoring unit of the third aspect detects whether or not each output side of the circuit unit is short-circuited. Outputs the operation result signal output by each of the circuit sections
F.

Accordingly, when the output side of each circuit section is short-circuited, although it is supposed to be duplicated, it has only a single function, but forcibly outputs the operation result signal of each circuit section. Is turned off, the safety of the electronic device can be improved.

The control unit for outputting the operation result signal of each circuit unit by the monitoring unit may be configured to also serve as the control unit for the operation result signal output of each circuit unit by another function of the electronic device.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to a safety area sensor used for detecting intrusion of a human body such as a press machine.

FIG. 1 is a functional block diagram of a safety area sensor according to an embodiment of the present invention. In the figure, the safety area sensor includes a light emitter 30 and a light receiver 40. If the light emitted from the light emitter 30 is not detected by the light receiver 40, the light is interrupted by the human body, and the human body press machine. In this case, the control output of the sensor is turned off, and the operation of the press machine is forcibly stopped.

In FIG. 1, the light projector 30 includes a light projecting unit 6 for projecting light onto a detection object. The light receiver 40 includes a main power supply 1, a second power supply 2, a power supply voltage monitoring unit 3 for monitoring the operation of the main power supply 1, a second monitoring unit 4 for monitoring the operation of the power supply voltage monitoring unit 3, and a light emitting unit 6. It includes a light receiving unit 5 for receiving light, a multiplexed channel CH1 and a channel CH2 for receiving a light receiving signal from the light receiving unit 5, detecting presence / absence of an object according to a light receiving state, and performing control output.

Channels CH1 and CH2 have the same configuration, and include an amplifying section 10 (20) for inputting, amplifying, filtering and outputting a light receiving signal, and for inputting an output signal from the amplifying section to reduce the light input level. It includes a determination unit 11 (21) for determining whether or not a predetermined level has been reached, that is, the presence or absence of an object, and an output circuit 12 (22) that performs a control output operation based on the determination output of the determination unit.

As described above, since the internal circuits of the sensor are multiplexed with the channels CH1 and CH2, if a failure is detected in one channel, the control output by the other channel is forced. When the sensor is turned off, the sensor is controlled to operate on the safe side.

In FIG. 1, there is only one main power supply 1,
The power supply voltage (5 V) is supplied by converting from an external power supply (24 V) to all modules except the power supply voltage monitoring unit 3.
The second power supply 2 different from the main power supply 1 supplies a power supply voltage (7 V) converted from an external power supply (24 V) to the power supply voltage monitoring unit 3.

It should be noted that the second power supply 2 may be configured so as not to convert the external supply voltage and to use the power supply voltage as it is.

FIG. 2 is a circuit diagram of the power supply voltage monitoring unit 3 of FIG. 1 and its peripherals. In FIG. 2, the power supply voltage monitoring unit 3 includes comparators 41 and 42. ON / O by the plurality of resistors and the second monitoring unit 4 in relation to the inputs of the comparators 41 and 42
FF controlled transistors TR1 and TR2 are provided.

During normal operation, the second monitoring unit 4 turns off the transistor TR1 and turns on the transistor TR2.
Since the comparator 41 is in the state, 5.5 V obtained by dividing the supply voltage (7 V) from the second power supply 2 by resistance is input to the non-inverting input terminal (+).
V is input to the inverting input terminal (-). The above-mentioned resistor-divided 4.5 V is input to the inverting input terminal (-) and the supply voltage 5 V from the main power supply 1 is input to the non-inverting input terminal (+) of the comparator 42.

Therefore, when the outputs of the comparators 41 and 42 are both ON, that is, when the supply voltage (5
When it is confirmed that V) is in the range of 4.5 V to 5.5 V, the control output by the output circuits 12 and 22 is turned on, and the output operation according to the normal light receiving state is maintained.

On the other hand, when the output of the main power supply 1 is out of the above range, the outputs of the comparators 41 and 42 are output from the output circuits 12 and 22.
And the control output is forcibly turned off.

Using the circuit of FIG. 2, it is possible to detect not only the failure of the main power supply 1 but also the failure of the second power supply 2 due to the output fluctuation of the second power supply 2. If the output voltage of the second power supply 2 changes from 7V to 0V, the output of the comparator 41 is inverted, so that the control output by the output circuit is turned off. When the voltage increases from 7 V to 24 V, the output of the comparator 42 is inverted, and the control output is similarly turned off.

FIG. 3 is a timing chart at the time of failure diagnosis of the power supply voltage monitor 3 by the second monitor 4 of FIG.
3 in FIG. 3 corresponds to the signal in FIG.

In FIG. 1, the second monitoring section 4 periodically performs a failure diagnosis of the power supply voltage monitoring section 3 using a microcomputer or the like as follows.

First, when the signal in FIG. 2 is set to 5 V, the transistor TR1 in FIG.
Of the non-inverting input terminal (+) becomes 0V. At this time, if the power supply voltage monitoring unit 3 has not failed, the output of the comparator 41 is inverted from ON to OFF, and an OFF (0 V) signal is supplied to the output circuits 12 and 22 ((A) in FIG. 3). reference).

If the outputs from the output circuits 12 and 22 do not become OFF (0 V) at this time (see FIG. 3C), the second monitoring unit 4 assumes that the power supply voltage monitoring unit 3 has failed. 2 and the output circuits 12 and 2
2 is forcibly turned off (0 V) (see FIG. 3D).

Next, the second monitoring unit 4 sets the signal to 0 V, turns off the transistor TR2, sets the inverting input terminal (-) of the comparator 42 to 7 V, and inverts the output of the comparator 42 to output circuits 12 and 22. Is turned off (0 V), that is, it is confirmed that the power supply voltage monitoring unit 3 has not failed (see FIG. 3B).

As described above, according to the configuration of FIG. 1, the failure of the main power supply 1 and the second power supply 2 can be detected by the power supply voltage monitoring unit 3, and the failure of the power supply voltage monitoring unit 3 can be detected by the second monitoring unit 4. When these failures are detected, the safety area sensor of FIG. 1 is forcibly turned off the control output and shifted to the safe side. Therefore, even if the main power supply 1 is not multiplexed, abnormal operation due to the failure of the main power supply 1 is performed. Can be reliably avoided.

Further, since the voltage used in the area sensor shown in FIG. 1 is supplied by a single main power supply 1, even if the internal circuits are multiplexed like the channels CH1 and CH2, the voltage between the channels may be reduced. There is no potential difference, and normal transmission and reception operations between channels are guaranteed.

FIG. 4 is a diagram showing another configuration of the light receiver 40 of FIG. 4 has the same function as the second monitoring unit 4 of the light receiving unit 40 of FIG.
5 is built in the CPUs 13 and 23 together with the determination units 14 and 24 for the channels CH3 and CH4, respectively, and constitutes one function of the microcomputer. The other configuration is the same as that of FIG. 1 and the description is omitted.

In the figure, when each of the second monitoring units 15 and 25 detects an abnormality of the power supply voltage monitoring unit 3 as described above, the control outputs of the output circuits 12 and 22 are turned off. At this time, the control outputs of the output circuits 12 and 22 are turned off.
This function is shared with the output control function of the original object detection function by the determination units 14 and 24 of the sensor as shown.

FIG. 5 is a block diagram of a multi-optical axis photoelectric sensor to which the light receiver 40A of FIG. 4 is applied.

FIG. 6 is a diagram showing still another configuration of the light receiver 40 of FIG. In the figure, signals outputted from each circuit are shown. In the light receiver 40B of FIG. 6, similarly to FIG. 4, the second monitoring units 18 and 28 serve as microcomputer functions together with the determination units 17 and 27, respectively.
In addition to being incorporated in the CPUs 16 and 26 of H5 and CH6, the power supply voltage monitoring unit 3B includes an upper limit detection unit 43 for monitoring the upper limit voltage and a lower limit detection unit 44 for monitoring the lower limit voltage.

The upper and lower limit detectors 43 and 44 correspond to the comparators 41 and 42 in FIG. The other configuration of the light receiver 40B is the same as that of FIG.

In the figure, the output of the upper limit detector 43 is connected to the output circuit 12 of the channel CH5, and the output of the lower limit detector 44 is connected to the output circuit 22 of the channel CH6.
Also, the second monitoring units 18 and 2 of the CPUs 16 and 26
8 is fed back with the output signals of the output circuits 12 and 22, and outputs a signal based on the two input signals and outputs a signal based on the two input signals.
And 22 are controlled. For example, if the input signal indicates that the control output of the output circuit 12 is forcibly turned off and the input signal does not indicate the forcible OFF state, the second monitoring unit 28 outputs a signal to output the output circuit 12. Control 22 is forcibly turned off. Second
The monitoring unit 28 operates similarly. Therefore, the output circuit 1
2 and 22 receive input signals individually by the upper and lower limit detectors 43 and 44 of the power supply voltage monitor 3B,
Since the output signal is fed back to the second monitoring units 18 and 28, the control output is controlled to be simultaneously forced OFF.

FIG. 6 shows duplexing using the second monitoring units 18 and 28, but the second monitoring unit
A configuration in which a monitoring unit exists may be employed.

Further, only the signal from the second monitoring unit 18 of the channel CH5 controls the power supply voltage monitoring unit 3B, but this can be controlled by both of the duplexed second monitoring units 18 and 28. A configuration may be used, or a configuration in which the power supply voltage monitoring unit 3B is controlled by a logical product or a logical sum of the two signals.

FIG. 7 is a timing chart of the failure diagnosis of the power supply voltage monitoring unit 3B by the second monitoring unit 18 of FIG. 7 in FIG. 7 correspond to the signals in FIG.

As shown in FIG. 2, the upper limit detection unit 43 receives a signal from the second monitoring unit 18 by a periodic process of the microcomputer.
Is diagnosed (see FIG. 7A), only the control output of the output circuit 12 is turned off. When the lower limit detection unit 44 is diagnosed by the signal as shown in FIG. 2 (see FIG. 7B), only the control output of the output circuit 22 is turned off. In any case, when the control output of the corresponding output circuit is not turned off, the power supply voltage monitoring unit 3B is regarded as a failure and forcibly turns off the control outputs of the output circuits 12 and 22 by a signal. To the safe side.

If the output circuit 12 and the output circuit 22
If the output side is short-circuited, the control output of the output circuit 12 must be OFF and the control output of the output circuit 22 must be ON if the signal is normal when the signal is output. OFF
(See FIG. 7C). Also in this case, the control output of the output circuits 12 and 22 is forcibly turned off by the signal, and the sensor is shifted to the safe side (FIG. 7).
(D)).

FIG. 8 is a view showing the appearance of a press provided with a safety area sensor according to an embodiment of the present invention.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a safety area sensor according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a power supply voltage monitoring unit of FIG. 1 and peripheral circuits thereof;

FIG. 3 is a timing chart at the time of failure diagnosis of a power supply voltage monitoring unit by a second monitoring unit in FIG. 2;

FIG. 4 is a diagram illustrating another configuration of the light receiver of FIG. 1;

FIG. 5 is a block diagram of a multi-optical axis photoelectric sensor to which the light receiver of FIG. 4 is applied;

FIG. 6 is a diagram showing still another configuration of the light receiver of FIG. 1;

7 is a timing chart of a failure diagnosis of a power supply voltage monitoring unit by a second monitoring unit in FIG. 6;

FIG. 8 is a diagram showing an appearance of a press provided with a safety area sensor according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main power supply 2 Second power supply 3 and 3B Power supply voltage monitoring unit 4, 15, 18, 25, 26 Second monitoring unit CH1 to CH6 Channels 12, 22 Output circuit Note that the same reference numerals in the drawings indicate the same or corresponding parts. .

Claims (4)

[Claims] 1. An electronic device that receives a drive voltage from an external power supply and operates to output an operation result signal, wherein a voltage from the external power supply is input and output to and supplied to each unit of the electronic device. A power supply unit; a diagnosis unit that diagnoses a failure of the first power supply unit based on an output voltage level of the first power supply unit; and a first power supply that inputs a voltage from the external power supply and supplies the voltage to the diagnosis unit. And a second power supply unit different from the unit, wherein the diagnostic unit turns off the output of the operation result signal by the electronic device when diagnosing the failure. 2. The electronic device according to claim 1, further comprising a monitoring unit that monitors whether a function of the diagnosis unit operates normally. The monitoring unit is configured to perform the operation by the electronic device when detecting that the function of the diagnosis unit does not operate normally. 2. The electronic device according to claim 1, wherein the output of the operation result signal is turned off. 3. The circuit unit for performing the operation and outputting the operation result signal is duplicated, and the diagnostic unit is configured such that a voltage supplied to each of the circuit units by the first power supply unit is an upper limit value. And an upper limit detection unit that turns off the output of the operation result signal by one of the circuit units in response to exceeding the threshold value, and a voltage supplied to each of the circuit units by the first power supply unit exceeds a lower limit value. And a lower limit detecting unit that turns off the output of the operation result signal by the other electric circuit unit, wherein the monitoring unit operates at least one of the upper limit detecting unit and the lower limit detecting unit normally. 3. The electronic device according to claim 2, wherein when detecting that the operation is not performed, the output of the operation result signal by each of the circuit units is turned off. 4. The monitoring unit detects whether each output side of the circuit unit is short-circuited, and when detecting the short-circuit, turns off the output of the operation result signal by each of the circuit units. The electronic device according to claim 3, wherein: