JP2927594B2 - Control method of optical coupling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupling device such as a photo-interrupter for detecting the presence or absence of an object without contact, and a control method therefor.

[0002]

Conventional photo-interrupter 1, those of the analog output, as shown in FIG. 4, is composed of the light emitting element 2 and the light receiving element 3, and the reference voltage V _REF to the output V _E by an external comparator 4 The values are compared and input to a CPU or the like as a binary output V _O of “H” or “L”. _{Alternatively,} the output of VE was directly input to a CPU or the like.

[0003]

In the above-mentioned prior art, the photointerrupter 1 is roughly classified into two types, a transmission type and a reflection type. The transmission type is a type in which light emitted from the light emitting element 2 as shown in FIG. Are directly incident on the light receiving element 3, and the object is detected by utilizing the fact that the detection object 5 blocks this light and reduces the amount of received light.

[0006] The reflection type has a structure in which light emitted from a light emitting element 2 is reflected from a detection object 5 and enters a light receiving element 3 as shown in FIG. The object is detected by utilizing the fact.

In the circuit of FIG. 4, when _VE is not saturated,
The following relationship holds:

[0006]

(Equation 1)

[0007] When detecting the presence or absence of an object may be set to circuit constants so that the reference voltage V _REF is present between the V _E of V _E and Mutoki when chromatic detection object (see Figure 7).

However, there are the following variations and variations in the above equation.

K and k have variations such as deviation of the optical axis due to the assembly.

[0010] Φ _E is an individual variation, a change over time (MAX
50% down / 50,000H), there is a change due to temperature.

Ic has individual variations and changes due to temperature.

A has variations due to individual detection objects.

B has variations due to individual detection objects.

Therefore, in actual use, in the circuit of FIG. 4, the resistance R ₁ or R ₂ is adjusted for each device, and the light emitting element 2, light receiving element 3, and photo interrupter 1 are finely ranked. There was a problem that it had to be used separately.

In the reflection type photo interrupter, the amount of light reflected from the background when there is no detection object 5 is large.
In many cases, the output difference between the presence and absence of the detection object 5 cannot be made much. For this reason, in consideration of the above-mentioned variation of Φ _E such as a change with time, there arises a problem that V _REF cannot be set and cannot be used.

In view of the above, an object of the present invention is to provide an optical coupling device which can be used even if there is a variation in output of a photo interrupter or the like, a variation due to temperature, aging, etc., and a small difference in the amount of received light with or without an object to be detected. And a control method thereof.

[0017]

Means for Solving the Problems An object of the present invention is to provide an external control device for driving an optical coupling device which converts an amount of received light which varies depending on the presence or absence of a detected object into an electric signal and outputs the electric signal. Is to store the output value from the optical coupling device at regular intervals, or
Memorize the output value from the optical coupling device obtained based on
By comparing the output value from the optical coupling device taken in when judging the presence or absence of the detection object with the stored value, the presence or absence of the detection object, or from presence to absence, from absence to existence It is to determine the change. This judgment is
When the codes match, the light emitting element and light receiving element
It is performed after a certain period of time after the source is supplied.

[0018]

[0019] Then, the optical coupling device includes a comparator for comparing a memory circuit for storing a self identification code and the identification code sent from the identification code and an external control device, based on an output of said comparator circuit emitting An output control circuit that supplies power to the element and the light-receiving element, and analog-to-digital converted electricity
An output unit for digitally outputting a signal. Output section
Sends an identification code receipt signal when the identification codes match.
One signal line with the output value based on the amount of received light
Output.

[0020]

[Action] In the above Symbol challenges solving means, the external control device,
Storing the output values sent Ri by optical coupling equipment, detected object
When determining the existence of, Installing elaborate optical coupling equipment output
The value is compared with the stored output values. Taking the time difference between the output of the time to determine that the stored output to the optimum, the output variation due to temperature or aging is able to ignore.

Further, the output of the optical coupling equipment which is also stored, since the output of the optical coupling instrumentation 置自 only, of course, the output of the light emitting <br/> element, variations in sensitivity of the light receiving element and Even if there is assembly variation, individual output value variations of the optical coupling device can be ignored.

The output value of the light receiving element 3 is transmitted digitally.
Output, for example, the output value is 8-bit data
And eight signal lines D / IO are also possible.
However, in such a case, the number of optical coupling devices used increases.
Then, it depends on the number of wires in the device and the connector
The number of connection points increases. Therefore, downsizing of equipment and defective rate
To reduce the number of signal lines, reduce the number of lines in the equipment.
And reduce the number of connection points by connectors and the like.

[0023]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an optical coupling device showing an embodiment of the present invention, and FIG. 2 is a timing chart thereof.

As shown in the figure, an optical coupling device (photo interrupter) 1 of the present embodiment controls a light emitting element 2, a light receiving element 3 including an amplifier and an output transistor, and a drive control of the light emitting element 2 and the light receiving element 3. And an internal control element 10.

As shown in FIG. 1, the internal control element 10 is connected to an external control device 11 through four input / output terminals of a power supply line Vcc, a ground line GND, a clock line CLK and a signal line DI / O. .

The internal control element 10 is connected to the external control device 1
1 to the clock line CL through the signal line DI / O
An input shift register 12 for reading a data bit string sent in synchronization with the K clock signal, and a storage circuit (address memory) 13 for storing its own identification code in advance
An address comparison circuit 15 for comparing the data (identification code) read into the shift register 12 with the data (own identification code) stored in the address memory 13; Comparison circuit 15
Determines that the identification codes match, an output control circuit 16 that supplies power to the light emitting element 2 and the light receiving element 3, a timing control circuit 17 that controls the clock timing, and a timing determined by the timing control circuit 17 Accordingly, a signal generation circuit (ACK generation circuit) 19 which outputs the detection state result DO input from the light receiving element 3 to the external control device 11 through the signal line DI / O from the output gate circuit 18 along with the identification code reception signal ACK. , Light receiving element 3
Analog-to-digital converter (hereinafter referred to as A / D converter) for converting an electric signal corresponding to the amount of received light from analog to digital
1 and an output shift register 22 as an output unit for reading a digital signal from the A / D converter 21 and outputting a signal from the output gate circuit 18 in accordance with the timing determined by the timing control circuit 17. ing.

Here, the external control device 11 does not generate a clock signal except when communicating the identification code through the signal line DI / O in order to make the optical coupling device surely grasp the start time of reading the identification code. As shown in FIG. 2, this clock signal is Hi except during communication.
gh state, and a Low output is input before the identification code. Therefore, the timing control circuit 17 performs two or more initial signal lines DI / O of the clock signal on the signal sent from the external control device 11.
Is used to confirm the synchronization between the clock signal and the identification code.

A parity signal PTY is added to the end of the 8-bit identification code data bit string sent from the external control device 11, and the internal control element 10 checks the number of bits of this code signal to determine the identification signal. A parity check circuit 24 is provided to detect a code reading error.

The address is written by the memory write control means 26 before or after the attachment to the device having the external control device 11. Then, as this address writing method, R
An AM method, a charge injection method, a junction destruction method, a fuse fusing method and the like can be considered.

On the other hand, the external control device 11 has a storage means 31 for storing the output of the photointerrupter 1 at regular intervals.
And when it is desired to determine the presence or absence of the detected object, the determination unit 32 compares the latest output of the photointerrupter 1 with the previously stored output to determine whether the state of the presence or absence of the detected object has changed. Have.

Next, the operation of the optical coupling device will be described in detail with reference to the timing chart of FIG. First, the clock line CLK and the signal line DI / O connected to the external control device 11 are set to High when the optical coupling device is not operated.
h state is maintained.

When it is necessary to know the detection state of the optical coupling device, the external control device 11 outputs a clock signal and an identification code synchronized with the clock signal. At this time, only when the state of the DI / O terminal is High at the time of the first clock falling and Low at the time of the second clock falling by the timing control circuit 17, the subsequent DI / O states are changed from DI0 to DI7 in FIG.
(8 bits) is read into the shift register 12 as an identification code.

That is, the identification code sent from the external control device 11 is synchronized with the clock signal CLK sent from the external control device 11 as shown in FIG. The optical coupling device confirms with the timing control circuit 17 that the output becomes High when the first clock of the clock signal is High and the output is Low when the second clock is falling, in the High state and before the identification code. . If the clock timing is OK, the subsequent eight bits DI0 to DI7 are taken in as identification codes. This allows the optical coupling device to check the synchronization deviation due to noise between the clock signal and the code signal on the signal line DI / O.

Further, in this example, the 8-bit DI0 to DI0
A parity signal PTY is inserted into the I7 code to form a 9-bit code signal, and the number of bits of this code signal is checked by the parity check circuit 24 to detect a parity error. When the occurrence of the parity error is confirmed, the output control circuit 16
Power is not supplied to the light emitting element 2 and the light receiving element 3 from the O1 power supply line 28, and power is supplied to the light emitting element 2 and the light receiving element 3 only when occurrence of a parity error is not confirmed. Therefore, an error due to noise in the code signal, that is, an error in reading the identification code can be checked.

The address comparison circuit 15 compares the self identification code in the address memory 13 with the identification code in the shift register 12 read by the signal line DI / O. Power is supplied to the O1 power supply line 28 of the light emitting element 2 and the light receiving element 3 only when the values match, and the light emitting element 2 and the light receiving element 3 are driven.

Here, when the conventional optical coupling device is used, the power of the all optical coupling device is always turned on. In this embodiment, however, in FIG. The light-emitting element 2 and the light-receiving element 3 are the same as those described above, and this part is only the optical coupling device whose identification code sent from the external control device 11 matches its own identification code stored in advance. Operate only for a certain period of time, and the other all-optical couplers whose identification codes do not match do not operate, so that the current consumption can be significantly reduced.

Then, an analog electric signal is read from the line 27 in accordance with the output of the light receiving element 3, ie, the presence or absence of the detected object, and is digitized by the A / D converter 21.
It is input to the output shift register 22 as an 8-bit signal. Next, the ACK generation circuit 19 detects the detection state result DO at the timing determined by the timing control circuit 17.
To the identification code reception signal ACK and output gate circuit 1
8 and the output gate circuit 18 outputs the two signals DO,
ACK is output to the external control device 11 through the signal line DI / O line. In this example, the identification code reception signal ACK is output in synchronization with the rising edge of the 13th clock, and the detection state result DO is output in synchronization with the rising edge of the 14th clock.

On the other hand, as shown in FIG. 3, the external control device 11 stores the output of the photointerrupter 1 in the storage means 31 at regular intervals. Then, when it is desired to determine the presence or absence of the detected object, the latest output of the photointerrupter 1 is compared with the previously stored output to determine whether or not the state of the presence or absence of the detected object has changed. If the photointerrupter 1 of FIG. 1 is used, if the detected object changes from absent to present, D _N > D _O , so that erroneous detection can be prevented by setting appropriate l and L in some cases. Incidentally, in FIG. 3, D _N are output in recent photointerrupter, D _O is the output of a certain time before the photo-interrupter, L, l is a constant that is a criterion for presence or absence of an object.

As another embodiment, the external control device 11
The output of the photointerrupter when the presence or absence of the detected object is stored in the memory is stored, and when it is desired to determine the presence or absence of the detected object, the output is taken and the output of the photointerrupter is compared with the previously stored output to detect the detected object. Can also be determined.

As described above, the detection state result DO is output to the external control device 11 through the signal line DI / O following the identification code reception signal ACK, so that the external control device 11 such as a copying machine can output a plurality of optical signals. When connecting a coupling device, the clock line CLK and the signal line DI / O can be shared between the optical coupling devices 1 and connected to the external control device 11. For this reason, the wiring in the device is simplified as compared with the case where the conventional optical coupling device is used.

Further, since the optical coupler that matches the identification code sends the identification code acknowledgment signal ACK to the external control device 11, it is confirmed that this identification code acknowledgment signal ACK is sent for the all-optical coupler. If the external control device 11
It can be seen from FIG. 4 that the connection to the optical coupling device has been made, so that a connection check at the time of manufacturing the device and a connection check at the time of turning on the power at the time of using the device can be performed.

Here, it is confirmed that no parity error has occurred in the signal line DI / O of FIG. 2, and a certain period of time has elapsed after power was supplied through the O1 power supply line 28 of the light emitting element 2 and the light receiving element 3. The reason why the detection state result DO is output is that the detection state result DO is output in a state where the output 27 of the detected object detection of the light receiving element 3 is stable.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention.

For example, in this embodiment, the transmission type photointerrupter has been described. However, the configuration may be such that the presence or absence of an object to be detected is detected using a reflection type photointerrupter.

[0045]

As apparent from the above description, the external control unit stores the output values sent from the optical coupler,
Because Installing elaborate an output value of the latest optical coupling device is compared with the stored output values, if perfect take the time difference between the output,
Output changes due to temperature or aging can be ignored.

Since the stored output of the optical coupling device is also the output of the optical coupling device itself, naturally, even if there is a variation in the output of the light emitting element, the sensitivity of the light receiving element, and the assembly, the optical coupling device does not. Individual output value variations of the device are negligible.

Further, the optical coupling device supplies power to the light receiving / emitting element when its own identification code and the identification code from the external control device match, so that the power consumption of the optical coupling device can be greatly reduced. I can do it. And for a certain time after power supply
If the judgment is made after opening, the light receiving element will come out in a stable state.
Therefore, the reliability of the detection result can be improved.
Furthermore, the identification code is received from the optical coupling device to the external control device.
Signal from the external control unit,
Connection is made to the
Checking connection of devices and connections when using devices
Can be done.

[Brief description of the drawings]

FIG. 1 is an internal connection diagram of an embodiment of a photointerrupter of the present invention.

FIG. 2 is an input / output timing chart of one embodiment of the photointerrupter of the present invention.

FIG. 3 is a control flowchart of the photointerrupter of the present invention.

FIG. 4 is a circuit diagram of a conventional analog output photointerrupter and an external circuit.

FIG. 5 is a structural view of a conventional transmission type photo interrupter.

FIG. 6 is a structural diagram of a conventional reflective photointerrupter.

FIG. 7 is an explanatory diagram of V _E and V _REF setting.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photo interrupter 2 Light emitting element 3 Light receiving element 4 Comparator 5 Detected object 10 Internal control element 11 External control device 12 Input shift register 13 Address memory 15 Address comparison unit 16 Output control circuit 17 Timing control circuit 18 Output gate circuit 19 ACK generation unit Reference Signs List 21 A / D converter 22 Output shift register 26 Memory write controller 31 Storage means 32 Judgment means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-296680 (JP, A) JP-A-63-47691 (JP, A) JP-A-60-27882 (JP, A) 133357 (JP, U) Actual opening 60-65838 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01V 9/04 G01J 1/42 H04L 11/00

Claims (3)

(57) [Claims] An optical coupling device that has a light emitting element and a light receiving element, converts an amount of received light that varies depending on the presence or absence of a detection object into an electric signal, and outputs the electric signal, a storage circuit that stores its own identification code.
And the identification code and the identification code sent from the external control device
And a comparison circuit for comparing
Output control circuit that supplies power to light emitting and light receiving elements
Output the analog-to-digital converted electrical signal
When the optical coupling device is driven by an external control device, the external control device outputs the output from the optical coupling device.
By storing the value, comparing the output value from the optical coupling device taken in when determining the presence or absence of the detection object with the stored value, the presence or absence of the detection object, or presence or absence, A method for controlling an optical coupling device, comprising: determining a change from absence to presence. 2. An output unit according to claim 1 , wherein said identification codes match.
Output the identification code reception signal to the
Serial output to one signal line together with the output value
The control method for an optical coupling device according to claim 1, wherein: 3. A light emitting device when the identification codes match.
After a certain period of time after supplying power to the
Method of controlling an optical coupling device according to claim 1 or 2, wherein the performing constant.