JP2683935B2 - Optical sensor level adjustment circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] The present invention relates to a level adjusting circuit for an optical sensor, and an object of the present invention is to provide a level adjusting circuit for automatically adjusting each sensor level by sequentially switching a plurality of optical sensors. A sensor switching unit that sequentially switches the sensors, a level varying unit that adjusts the level of the switched optical sensor output, a voltage comparing unit that compares the level output of the level varying unit with a reference voltage, and an output of the voltage comparing unit. Input a value and start up-counting a plurality of times for each optical sensor that has been switched according to the level state of the output, change the level of the level variable unit according to the output value, and use the sensor output after level variation as a reference. Voltage (1
4) A configuration is provided that includes a counter unit that stops up-counting when the above is reached, and a memory unit that stores the output value of the counter unit in the stopped state.

[Industrial applications]

The present invention relates to a level adjusting circuit for an optical sensor.

[Conventional technology]

2. Description of the Related Art Conventionally, an optical sensor is arranged in each main part for detecting a passing state of a medium such as a banknote in a medium conveying path of a device such as an automatic teller machine (ATM). In this case, it is desired to adjust the level of each sensor quickly and uniformly.

FIG. 5 is an explanatory view of a conventional example, in which each sensor is adjusted as a separate system. That is, each sensor 1 ₁ to 1 _n consists of a light emitting element and a light receiving element, enter a light receiving element output to each negative terminal of the voltage comparator 2 ₁ to 2 _n, the reference voltage 4 is the positive terminal to the common each sensor Is being supplied. The volume 3 ₁ to the bias circuit of the negative terminal side of each sensor
3 _n are provided, the level of each sensor is adjusted individually, and the adjusted level output is input to the input port 5.

[Problems to be solved by the invention]

In the configuration of the conventional example shown in FIG. 5, it is necessary to repeatedly check and readjust one by one at the time of maintenance and inspection, and there is a drawback that it takes a lot of adjustment time and adjustment time because the measuring devices are switched separately.

An object of the present invention is to provide a level adjustment circuit that sequentially switches a plurality of optical sensors and automatically adjusts each sensor level.

[Means for solving the problem]

To achieve the above object, as shown in the principle diagram of Fig. 1, the level adjusting sensor switching unit 12 sequentially switches the plurality of optical sensors 1 ₁ to 1 _n, the level of the optical sensor output is changed該切A variable unit 13, a voltage comparison unit 15 that compares the level output of the level variable unit with a reference voltage 14, and an output value of the voltage comparison unit that is input to each optical sensor that is switched according to the level state of the output. The up-counting is started a plurality of times, the level of the level variable unit is changed according to the output value, and the sensor output after the level is changed is the reference voltage (1
4) A counter section 16 that stops up-counting when the above is reached, and a memory section 17 that stores the output value of the counter section in the stopped state
And the configuration.

[Action]

A loop for comparing the reference voltage in FIG. 1 and the output of the level varying unit 13 in the voltage comparing unit 15, counting up the counter unit 16 with the output value, returning the value to the level varying unit 13, and changing the level. By the circuit, the voltage comparison unit 15 stores this output value as a set value when the sensor output after the level change becomes equal to or higher than the reference voltage 14. Then, in the case other than the normal count, it is stored as an error signal.

〔Example〕

FIG. 2 is an explanatory view of the configuration of the embodiment of the present invention. Third
FIG. 4 (a) and FIG. 4 (b) show operation explanatory views of the main part thereof.

Here, components having the same functions as those in FIG. 1 are designated by the same reference numerals.

In Figure 2, the outputs of the plurality of sensors 1 ₁ to 1 _n performs switching address in the analog multiplexer 12 of the sensor switching section, placed to the negative terminal of the voltage comparator 15 through a level changing unit 13. To switch the address of the analog multiplexer 12, a clock unit 18 not shown in FIG.
The counter (2) 18 ₁ and the counter (3) 18 ₂ provided therein are used.

Figure 3 shows this counter (2) 18 ₁ and counter (3) 18 ₂
9 shows the operation of the sensor selection unit using. That is, a CP (for example, a clock pulse of 0.5 μs) is input to the counter (2) 18 ₁ together with the counter (1) 16 which is a main part of the present invention described later. CP in the counter (2) 18 ₁ in the figure
Q output QA pulse when input is expressed in hexadecimal is CR
The (carrying) output has the illustrated waveform. The CR (Kiyarii) a counter (3) 18 ₂ put as clock, to obtain a basic output QA, to obtain QB, a frequency-divided of QC and fed back to this, the sensor select address is obtained by a combination thereof, This is repeated by CR (carry). The sensor select address created in this way is sent to the analog multiplexer 12, and the sensors are sequentially distributed.

Further, this sensor select address is simultaneously sent to the registers 17 _{1 to} 17 _n corresponding to the sensors of the memory unit 17 described later through the decoder 18 ₃ and the similar register allocation is performed.

As described above, the sensor output distributed in this way is input as the negative terminal input of the voltage comparator 15, and the voltage divider circuit 14 ₁ in the reference voltage generator 14 supplies V
Two reference voltages of 2, V1 are switched and supplied by the analog multiplexer 14 _{2 according} to a signal from the external port 6 ₁ . here,
V2 = 4.4V is the level in the transparent state without medium, V1 = 2.2V
Is the level at which the medium is detected.

The level variable unit 13 for the selected sensor output is
Connected to U19 data bus and input port 5 ₁ . Also,
The output of the counter (1) 16 back through the OR circuit 13 ₁ changes the level of the variable portion 13. That is, volume
The tap of 13 ₂ is disconnected by the analog switch S to change the resistance value.

When adjusting the level, set the reference voltage to V2, and when the sensor output is V2 or less, the output of voltage comparator 15 is "H", counter (1) 16 is EN (enable), and it counts with the rising signal of CP. Up. Voltage comparator 15 when V2 is exceeded
Output becomes "L", and the counter (1) 16 stops while holding the data.

When the counter (2) 18 ₁ counts 15 (hexadecimal F), CR (carry) is output, and the register 17 in the register unit 17 corresponding to each sensor is output at the output timing.
The count value of the counter (1) 16 is set to _{1 to} 17 _n .

Next, when detecting the medium, the reference voltage is set to V1 (2.2V), the counter (1) 16 is reset and all the outputs become "L", and the counter (3) 18 ₂ receives the sensor select data. was excisional directly from MPU 19, the output value of the voltage comparator 15 is monitored by the MPU 19 via the input port 5 _2.

FIGS. 4 (a) and 4 (b) are explanatory diagrams by an example of the operation of the counter unit and the level varying unit.

It corresponds to the QA of the counter 2 in FIG. 5A, and shows the output of the level variable unit, the output of the counter 1, the output signal of the voltage comparator, and CR (carry).

That is, when the sensor 1 reaches 4.4V with the "A" count at the counter (1) 16 and the output value "A" is set in the register, but the sensor 2 level does not rise during the counting up. The count continues until the last F, and "E" is set in the corresponding register. This means an error signal and indicates that the sensor 2 is unusable due to dirt, failure or the like.

FIG. 2B shows an example of a volume configuration of the sensor input of the level variable unit, that is, the voltage comparator 15.

In the same figure (b), the volume is divided by taps as shown, and analog switches ASW1 to 4 are provided between them, and the disconnection signals are supplied to ASW1 to ASW4 as shown in the data example of the output data of the counter (1) As a result, a combined resistance value corresponding to each data is given, and a waveform as shown in the output of the level variable portion of FIG.

〔The invention's effect〕

As described above, according to the present invention, a plurality of sensors are sorted by address, the reference voltage is sequentially applied to change the level, and the normally reached output value and the abnormal state are memorized. The sensor state can be automatically adjusted at high speed.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of the present invention, FIG. 2 is a diagram for explaining the configuration of the embodiment, FIG. 3 is a diagram for explaining the details of the sensor selecting unit of the embodiment, and FIG. 4 is a counter unit and a level varying unit of the embodiment. 5 is a detailed explanatory view of the conventional example, in which 1 ₁ to 1 _n are sensors, 12 is a sensor switching unit, 13 is a level changing unit, 14 is a reference voltage generating unit, and 15 is a voltage comparison unit. Section, 16 is a counter section, 17 is a memory section, 18 is a clock section, and 19 is an MPU.

Claims (2)

(57) [Claims] 1. A sensor switching unit (12) for sequentially switching a plurality of optical sensors (1 ₁ to 1 _n ), a level variable unit (13) for adjusting the level of the switched optical sensor output, and the level variable. A voltage comparator (15) that compares the level output of the unit with the reference voltage (14) and the output value of the voltage comparator are input, and a plurality of times are output for each optical sensor that is switched according to the level state of the output. A counter section (16) for starting up-counting, changing the level of the level variable section according to the output value, and stopping up-counting when the sensor output after level-changing becomes a reference voltage (14) or more; Memory section (1 that stores the output value of the counter section in the stopped state
An optical sensor level adjusting circuit comprising: 7), wherein the level is set by the output value of each optical sensor stored in the memory section during adjustment. 2. An error signal is stored in the memory unit (17) when a normal output value is not obtained when the level of the level changing unit is changed according to the output value from the counter unit (16). The optical sensor level adjusting circuit according to claim 1, characterized in that.