JPH10246662A - Electronic type water meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic type water meter which can carry out accurate integration and reverse judgment by intermittently supplying a current to a magnetic sensor to lower consumed current gradually. SOLUTION: One of the cycles of signals (a) and (b) to be outputted from a magnetic sensor 1 is measured by a cycle measuring section 5 and when the results of the measurement exceed a specified cycle, an overflow signal is outputted. Receiving the overflow signal, a stop/fine flow rate mode control section 4 works so that a sampling signal of the magnetic sensor 1 is switched over to a slow sampling. Under a slow sampling state in the stop/fine flow rate mode, when changes in the signal outputted by the magnetic sensor 1 are detected by a state change detecting section 3, a control is made to switch the sampling signal to a fast sampling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic water meter, and more particularly, to a magnetic sensor which magnetically detects the number of rotations of a rotating body that rotates according to the amount of water used.
The first and second signals are output, and based on the first and second signals, forward / reverse information indicating the rotation direction of the rotating body and a composite pulse of the first and second signals are output to an integrating unit. And an electronic water meter for integrating water consumption.

[0002]

2. Description of the Related Art FIG. 20 is a block diagram showing a configuration of a conventional electronic water meter. In the figure, 1 is a magnetic sensor, 2 is a forward / reverse determining unit that determines forward / reverse based on two signals output from the magnetic sensor, and outputs a pulse for integration by an integrating unit connected to the subsequent stage. And a composite pulse output unit. FIG. 21 shows an example of the forward / reverse determination unit and the composite pulse output unit 2. Two pulse signals having different phases according to the rotation of the rotating body detected by the magnetic sensor 1 are supplied to the input terminals a and b, and these two pulse signals are applied to the respective terminals of the flip-flops 29 and 30. Is done. The output terminal c outputs as many composite pulse signals as the number of pulses input to the terminal a irrespective of the rotation direction of the rotating body.
In the reverse rotation, the forward / reverse information at the “H” level is output.

When the rotational speed and the rotational direction of the rotating body are to be detected by the magnetic sensor 1, two pulse signals output from the magnetic sensor 1 must follow the rotational speed. A method of constantly supplying current is used.

[0004]

The method of constantly supplying a current to the magnetic sensor 1 as in the above-mentioned conventional electronic water meter has a problem that current consumption increases and it is uneconomical.

[0005] The present invention has been made in view of the above,
An object of the present invention is to provide an electronic water meter capable of performing accurate integration and forward / reverse determination while reducing current consumption by intermittently supplying current to a magnetic sensor.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, the number of rotations of a rotating body that rotates according to the amount of water used is magnetically detected by a magnetic sensor. The first and second signals are output, and based on the first and second signals, forward / reverse information indicating the rotation direction of the rotator and a composite pulse of the first and second signals are output to an integrating unit. An electronic water meter that integrates water consumption by measuring one cycle of the first and second signals output from the magnetic sensor, and when the measurement result is equal to or longer than a predetermined cycle. A period measuring unit that outputs an overflow signal to the stop, and a stop signal that receives the overflow signal and outputs a control signal that controls the sampling signal of the magnetic sensor to switch to a slower sampling to set the stop / micro flow rate mode. When the change of the signal output by the magnetic sensor is detected in the slow sampling state of the stop / fine flow mode set by the minute flow mode control unit and the stop / fine flow mode control unit, the sampling is switched to fast sampling. And a state change detecting unit that outputs a control signal for controlling the state change.

According to the first aspect of the present invention, one of the periods of the first and second signals output from the magnetic sensor is measured, and if the measurement result becomes longer than a predetermined period, an overflow occurs. When a signal is output, the sampling signal of the magnetic sensor is switched to slow sampling by the overflow signal, the stop / fine flow mode is set, and a change in the output signal of the magnetic sensor is detected in the slow sampling state of the stop / fine flow mode. Since the control is performed so as to switch to the fast sampling, the current consumption can be reduced while minimizing the count error.

[0008] The present invention according to claim 2 is based on claim 1.
In the invention described above, when the state change detection unit detects a state change, a forward / reverse determination mode in which a fast sampling signal is supplied to both the first and second signals to determine the rotation direction of the rotating body. A control unit, a sampling mode control unit that controls the sampling signal of the magnetic sensor to one of a low speed, a medium speed, and a high speed sampling signal according to a measurement result of the period measurement unit, and sets a corresponding sampling mode, A synthesizing pulse changeover switch that switches the first or second signal to the integrating unit in place of the synthesized pulse when the measurement result of the period measuring unit becomes equal to or shorter than a predetermined period. I do.

According to the present invention, when a change in the state of the output signal of the magnetic sensor is detected, a fast sampling signal is supplied to both the first and second signals to determine the rotation direction. By controlling the sampling signal of the magnetic sensor to one of low-speed, medium-speed, and high-speed sampling signals according to the cycle measurement result, and setting a corresponding sampling mode, and when the cycle measurement result falls below a predetermined cycle, Since the switching is performed so that the first or second signal is output to the integrating unit instead of the synthesized pulse, the forward / reverse can be accurately determined, the integration can be performed accurately, and the counting error can be minimized. it can.

Further, the present invention according to claim 3 provides the present invention as claimed in claim 2.
In the invention described, when the sampling mode set by the sampling mode control unit is switched from the low-speed sampling mode to another sampling mode, or when switching from another sampling mode to the low-speed sampling mode, the reciprocal information is invalidated. A low-speed mode change-time mask signal output unit, a normal / reverse information latch timing generation unit for generating a timing for latching the normal / reverse information, and the forward / reverse only when there is no change in the sampling mode after the sampling mode is determined. A forward / reverse information latch unit for latching information, and forward / reverse information switching for switching between using the forward / reverse information as it is or using an output signal from the forward / reverse information latch unit as forward / reverse information to the integrating unit A switch and the sampling mode control unit. If fast sampling mode set Te is the sampling pattern for applying a voltage only to the first signal side, and summarized in that and a high-speed mask signal output unit always disable the forward and reverse information.

According to the third aspect of the present invention, the normal / reverse information when switching from the low-speed sampling mode to another sampling mode or when switching from another sampling mode to the low-speed sampling mode is invalidated. Is latched only when the mode does not change after the determination is made, and switching is made between using the forward / reverse information as it is or using the output signal from the forward / reverse information latch unit. In the case of a sampling pattern in which a voltage is applied only to the signal side, since the forward / reverse information is always invalidated, the integrated value can be correctly counted.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the sampling pattern in the medium-speed sampling mode is based on first, second, and third frequency-divided signals obtained by sequentially dividing a reference signal. First to eighth defined
Is defined as one cycle of the medium-speed sampling mode,
The third to third sections are sampling on both the first and second signal sides, and the fourth to eighth sections are sampling patterns for applying a voltage such that sampling is performed only on the first signal side. When defined, medium-speed forward / reverse information latch permission to take in forward / reverse information only when forward / reverse of the rotator can be normally detected during sampling on the first and second signal sides in the middle-speed sampling mode state. A medium-speed forward / reverse latch signal output unit for capturing forward / reverse information when shifting from the first and second signal-side sampling to the first signal-side sampling state only; and the first and second If the medium-speed sampling mode is not set from the beginning to the end of both signal-side sampling sections, the medium-speed mode change mask signal output unit that invalidates the medium-speed forward / reverse latch signal And summarized in that a.

According to the present invention, the forward / reverse information is obtained only when the forward / reverse of the rotating body can be normally detected during sampling on both the first and second signal sides in the medium-speed sampling mode state. When the first and second signal side sampling are shifted to the sampling state only from the first and second signal side sampling, the normal / reverse information is fetched, and the medium speed sampling is performed from the beginning to the end of the first and second signal side sampling sections. When the mode is not the mode, the medium-speed forward / reverse latch signal is invalidated, so that the forward / reverse information can be taken in even at the middle speed, and the count error can be suppressed.

The present invention described in claim 5 is the same as the claim 2.
In the invention described in the first aspect, the sampling pattern in the medium-speed sampling mode is a first pattern obtained by sequentially dividing a reference signal.
The first to eighth sections defined by the second and third frequency-divided signals are defined as one cycle of the medium-speed sampling mode,
A sampling pattern for applying a voltage such that the first to third sections are sampling on both the first and second signal sides, and the fourth to eighth sections are sampling only on the first signal side. And a latch signal generating unit that outputs a latch signal each time one cycle of the first signal is detected in the medium-speed sampling mode state, and when the first and second signal-side samplings are performed, A medium-speed forward / reverse information latch permitting unit that permits latching of forward / reverse information only when forward / reverse can be normally detected; and a mode transition time mode output unit that masks forward / reverse information when there is a transition to the sampling mode. The gist is to have.

According to the fifth aspect of the present invention, a latch signal is output each time one cycle of the first signal is detected in the medium-speed sampling mode, and the first and second signal-side samplings are performed. Sometimes, the forward / reverse information is latched only when the forward / reverse is normally detected, and the forward / reverse information is masked when the sampling mode is shifted, so that the counting error can be minimized.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an electronic water meter according to one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a magnetic sensor, 2 denotes a forward / reverse judgment based on PA and PB signals generated from two signals a and b output from the magnetic sensor, and outputs forward / reverse information, and is connected to a subsequent stage. A forward / reverse determining unit that outputs a combined pulse to be integrated by the integrating unit, and a combined pulse output unit. Reference numeral 3 denotes a state change detection unit that monitors a change in the state of the PA signal. Reference numeral 4 denotes a stop & fine flow mode control unit that controls whether to enter the stop & fine flow mode or cancel the stop & fine flow mode. A period measuring unit comprising a counter which measures the period and outputs an overflow signal when the period becomes equal to or longer than a certain period, and a counter reset unit 6 which restarts the counter of the period measuring unit every time a falling edge of the PA signal is detected. Reference numeral 7 denotes a sampling voltage driver for supplying sampling signals SMPA and SMPB to the magnetic sensor 1. Reference numerals 8a and 8b denote signals a and b output from the magnetic sensor 1, respectively, for the sampling signal SMP from the sampling voltage driver 7.
A, D-type flip-flop (F / F) that latches with an inverted signal of SMPB.

The state change detecting unit 3, the stop & minute flow mode control unit 4, the cycle measuring unit 5, and the counter reset unit 6 used in the embodiment shown in FIG. 1 are configured as shown in FIG. Have been. That is, the state change detection unit 3
A flip-flop (hereinafter also referred to as F / F), A
An ND gate 3a and an inverter, the stop & minute flow mode control unit 4 is composed of one F / F and an inverter, the cycle measuring unit 5 is composed of a counter, and the counter reset unit 6 is a delay circuit 6a and 6c. F / F6b
And an inverter.

Next, the operation of the electronic water meter configured as described above will be described.

First, when the power is turned on (Power-on), the output UMODE signal of the AND gate 3a of the state change detection unit 3 is "1".
Stop at H "& output SMODE of micro flow rate mode controller 4
Becomes "L". The UMODE and SMODE signals are input to the sampling voltage driver 7 and SMODE = ”
Since the voltage is L ", a voltage is applied to the magnetic sensor 1 at a slow cycle in the stop & fine flow mode (" L "active).

In the stop & fine flow mode, the PA signal is "
The case where the level changes from L level to “H” level will be described with reference to the timing chart of FIG.
The MPA signal is an a-side sampling signal of the magnetic sensor 1, a
The signal is the a signal output of the magnetic sensor 1, the PA signal is the Q output of the flip-flop 8a, the UMODE signal is the output of the state change detection unit 3, and the SMODE signal is the output of the stop & minute flow mode control unit 4.

The signal a from the magnetic sensor 1 changes from "L" to "L".
When the signal changes to "H", the PA signal changes from "L" to "H" at the timing <1> in FIG. 3, and the UMODE signal changes to "H".
From "L" to "H", and the SMODE signal from "L" to "H". The UMODE and SMODE signals are input to the sampling voltage driver 7 and apply a voltage to the magnetic sensor 1 at a fast cycle because UMODE = “L”.

Next, when the count value of the cycle measuring unit 5 is smaller than a certain value (assuming that the count value is smaller than "F"), including the operations of the cycle measuring unit 5 and the counter reset unit 6, When the count value of the cycle measurement unit 5 becomes a certain value (= “F”), it is considered that the cycle has exceeded a certain period, and the overflow signal TOUT is output from the cycle measurement unit 5. The operation of switching from the fast sampling mode to the slow sampling in the stop & minute flow rate mode will be described with reference to the timing chart of FIG.

In FIG. 4, the PA signal is the Q output of the flip-flop 8a as in FIG. 3, (A) is the output of the delay circuit 6a of the counter reset unit 6, and (A) is the F / F.
(Flip-flop) The QN output of 6b, (c) is the output of the delay circuit 6c, (d) is the count value of the cycle measuring section 5, and the TOUT signal overflows the count value of the cycle measuring section 5 (count value = F overflows Then, the signal becomes the “L” level. UMODE, SM
The ODE signal is the same as the signal shown in FIG.

First, as described with reference to FIG. 3, <2> of FIG.
At the timing of & stop from the micro flow mode, SMO
Since the DE signal is "H", the reset of the counter of the cycle measuring unit 5 is released, and the counter starts counting up.
Next, when the PA signal changes from “H” to “L” (<2
>'), The signal (a) passing through the delay circuit 6a rises with a slight delay, the QN output (= (a)) of the F / F 6b is "L", and the signal (c) passing through the delay circuit 6c is After a short delay, the signal becomes "L", the F / F 6b is reset, and the signal (a) becomes "H" again. While this signal (a) is "L", the counter of the cycle measuring unit 5 is reset, and when the signal (a) becomes "H" again, counting starts. In this manner, the counter of the cycle measuring unit 5 restarts each time the falling signal of the PA signal is input, so that the overflow signal TOUT is not output and the operation continues in the fast sampling mode. Here, the timing <3 in FIG.
When the PA signal does not change as in>, the count value (D) of the cycle measuring unit 5 becomes “F”, the TOUT signal becomes “L”, and UMODE = “H”, SMODE = ”
L ”.

The UMODE and SMODE signals are input to the sampling voltage driver 7, and since SMODE = "L", a voltage is applied to the magnetic sensor 1 at a slow cycle in the stop & fine flow mode. The time during which the counter of the cycle measuring unit 5 outputs the overflow signal TOUT can be arbitrarily adjusted by adjusting the length of the counter. Here, a circuit for detecting a state change based on the PA signal, PA
The circuit that resets the counter of the cycle measuring unit 5 when the signal changes from "H" to "L" has been described. A method of detecting a state change based on the PB signal, and detecting a state change of each of PA and PB The PA signal changes from "L" to "H"
There is also a method of resetting the counter when it becomes.

FIG. 5 is a block diagram showing a configuration according to another embodiment of the present invention. In FIG.
Reference numerals 3, 4, 5, 6, and 7 denote the magnetic sensor, the forward / reverse determination unit & composite pulse generation unit, the state change detection unit, respectively, shown in FIG.
A stop & micro flow mode control unit, a period measurement unit, a counter reset unit, and a sampling voltage drive unit. 10 stops &
When the state change detecting unit 3 detects a state change in the minute flow rate mode, a control signal is output to the sampling voltage driving unit 7 so as to apply a fast sampling signal to both sides a and b in order to determine the rotation direction of the rotating body. A forward / reverse determination mode control unit 11 is a sampling mode control unit that controls whether the sampling mode is set to a high speed, a medium speed, or a low speed based on the measurement result of the cycle measurement unit 5.
Reference numeral denotes a decode timing generator for generating a read timing of the cycle measurement result. SW1 is a switch that switches between outputting the synthesized pulse to the integrating section as it is and outputting the PA signal, as described later in FIG.

Further, the sampling mode control unit 11
The sampling mode is controlled to one of the high-speed, medium-speed, and low-speed sampling modes based on the measurement result of the cycle measuring unit 5. These mode signals are output as HMODE, MMODE, and LMODE signals in FIG. It is supplied to the drive unit 7.

The forward / reverse determination mode control unit 10, sampling mode control unit 11, and decode timing generation unit 12 shown in FIG. 5 are configured in detail as shown in FIG. That is, the forward / reverse determination mode control unit 10 includes an AND gate 10a, a counter 10b, and an F / F 10c.
The sampling mode control unit 11 includes a decoder 11a, a comparator 11b, and an OR gate, and the decode timing generation unit 12 includes a delay circuit 12a, an F / F 12
b, 12c and an AND gate 12d.

Next, the operation will be described. First, when the power is turned on (Power-on), SMODE = “L”, UMODE = ”
H ", since the signal (e) output from the F / F 10c of the forward / reverse confirmation mode control unit 10 is" H ", HMODE ="
H ", MMODE =" H ", LMODE =" H ", and these MODE signals are output to the sampling voltage driver 7
Since SMODE = “L”, a voltage is applied to the magnetic sensor 1 at a slow cycle in the stop & fine flow mode. The operation when the state change detection unit 3 detects a change in the PA signal in the stop & minute flow mode and shifts to the high-speed or medium-speed mode via the forward / reverse determination mode will be described with reference to the timing chart of FIG.

When the state change detecting section 3 detects a change in the PA signal in the stop & minute flow rate mode, UMODE = "".
L ", SMODE =" H ", and the sampling voltage driving unit 7 applies a fast sampling signal to both sides a and b to the magnetic sensor 1 because UMODE =" L ", and passes through the delay circuit 12a of the decode timing generation unit 12. At the first rise of the signal (f) (timing <4> in FIG. 8), the Q output (g) of the F / F 12b becomes “H”, and the second rise of the signal (f) (<5 in FIG. 8). 8) since the Q output (h) of the F / F 12c becomes "H" at the timing (>) and the signal (h) is the AND output of the signals (h) and (h).
become that way. The count value of the cycle measuring unit 5 is input to the decoder 11a of the sampling mode control unit 11 and decoded at the timing when this signal (k) rises.

The comparator 11b of the sampling mode control section 11 has a comparison value in advance (for example, when the decoding value ≦ 3, the signal (co) = “L”, the signal (sa) = the signal (h) = “H”, When 3 <decode value ≦ 6, signal (S)
= "L", signal (co) = signal (h) = "H", and when decode value> 6, signal (h) = "L" and signal (h) = signal (h) = "H" (Note that the initial values are signal (co) = signal (sa) = "H" and signal (shi) = "L"). At the timing of <5> in FIG. 8, the signal (sa) = “L” and the signal (c) according to the decoded result (decoded value = 4)
= Signal (S) = "H". On the other hand, the rising signal at the timing <5> of the signal (f) is the F / F 10c.
And the Q output signal (E) of the F / F 10c is "
From "H" to "L", and since the signal (S) = "L", MM
Only the ODE signal becomes “L”. Since MMODE = “L”, the sampling voltage drive unit 7 applies the medium speed mode sampling voltage. When the mode shifts from the forward / reverse determination mode to the high-speed mode, the decoded value is 3 or less, and the other operation timings are the same as those in the case of the medium speed, and thus the description is omitted.

Next, FIG. 9 shows an operation for shifting to the low-speed mode in the case where no rising signal is generated in the decode timing generation section 12 (the PA signal does not fall twice) after the normal / reverse determination mode is set. At the first falling edge of the PA signal (timing <6> in FIG. 9), the Q output (G) of the F / F 12b of the decode timing generator 12 changes from "L" to "H". Since the second fall does not occur, the Q output (h) of the F / F 12c remains at the “L” level, and the signal (h) still remains at the “L” level. In this state, the normal / reverse determination mode cannot be exited forever, fast sampling is always performed on both sides a and b, and the current consumption is wasted. Then, a time-over signal is output (timing <7 in FIG. 9).
>). The signal (E) is generated by the rising signal of the signal (S).
Changes from “H” to “L”, and since the signal (S) = “L”, LMODB = “L”. Since LMODE = “L”, the sampling voltage driver 7 applies the sampling voltage in the low-speed mode.

As shown in FIG. 7, when either HMODE or MMODE is "L" (high-speed or medium-speed mode), the switch SW1 outputs the PA signal as it is and outputs the PA signal based on the PA signal. Count as integrated value, HMOD
E = MMODE = “H” (low speed or forward / reverse determination mode or
In the case of (stop & micro flow rate mode), a composite pulse is output and counted as an integrated value based on the composite pulse.

Here, the sampling pattern of each mode is, for example, a low-speed sampling with a and b both-side sampling and a sampling interval (T), and a medium-speed sampling pattern with a part of a and b both-side sampling (sampling interval (T / 4)). , Sampling only the remaining a (sampling interval (T))
Side only sampling (sampling interval (T / 2)),
The forward / reverse determination mode is prepared in advance such as sampling on both sides a and b (sampling interval (T / 4)).

FIG. 10 is a circuit diagram showing a configuration according to still another embodiment of the present invention. In the figure, 1 and 2 are the same as those shown in FIG. Reference numeral 16 denotes a low-speed mode change mask signal output unit for invalidating normal / reverse information when switching from the low-speed sampling mode to another sampling mode or from another sampling mode to the low-speed mode. A generation unit 18 is a forward / reverse information latch unit that latches forward / reverse information only when there is no mode change after the mode is determined. Switches SW2 and SW20 for switching whether to use the output signal of the reverse information latch section 18 are high-speed mask signal output sections that always invalidate the forward / reverse information in the high-speed mode. The latch timing generator 17 can be implemented with, for example, the same circuit configuration as the decode timing generator 12 shown in FIG.

The operation of the apparatus configured as described above will be described in detail with reference to the timing chart of FIG. The outputs of the magnetic sensor 1 when a voltage is constantly applied are shown in FIGS. 11A and 11B, and when the sampling signals applied from the sampling voltage driver 7 are SMPA and SMPB, PA and PB signals And forward / reverse judgment part &
FIG. 11 shows a composite pulse output from the composite pulse output unit 2 and forward / reverse information. (Here, even if the PA and PB signals change simultaneously, the PB signal is slightly reduced by a delay circuit so that a composite pulse is generated. Is delayed). Basically, in the low-speed mode, the rising signal of the output signal (k) of the latch timing generation unit 17 (same as the operation of the signal (k) of the decode timing generation unit 12 shown in FIG. 6) is input to the forward / reverse information latch unit 18. When this is done, the forward / reverse information is updated.

That is, the input signal (n) of the forward / reverse information latch section 18 rises at the first rise of the signal (q) (timing <8> shown in FIG. 11), and the forward / reverse information latch section 18 forward / reverse. Information is latched. At the second rising edge of the signal (q) (timing <9>), the mode shifts from the low speed to the high speed. When the low speed mode changes, the signal (q) of the mask signal output unit 16 is indicated by the hatched portion of the signal (q). ) Is masked, and the input (n) of the forward / reverse information latch unit 18 is "
In other words, the output Q of the forward / reverse information latch unit 18 does not change (in the section I, the high-speed waveform is sampled in the low-speed mode; Is recognized as a reverse rotation though it is a normal rotation, but does not capture the normal / reverse information.) The third rising edge and the fourth rising edge of the signal (q) correspond to the output signal of the high-speed mask signal output unit 20 ( The input (n) of the forward / reverse information latch unit 18 remains at the “L” level (the forward / reverse information is not taken in the high-speed mode).

At the fifth rising of the signal (G), the mode shifts from the high speed to the low speed. When the low speed mode changes, the signal (G) is indicated by the hatched portion of the signal (G) of the mask signal output unit 16. The input (n) of the forward / reverse information latch unit 18 is masked and remains at the “L” level (again, forward / reverse information is not taken in). At the sixth rising edge of the signal (g), the mode is not changed and the low-speed mode is maintained. Therefore, when the low-speed mode is changed, the mask signals of the mask signal output unit 16 and the high-speed mask signal output unit 20 are not output. The input signal (n) of the information latch unit 18 changes from "L" to "H", and the forward / reverse information is captured. The operation when shifting from the low-speed mode to the medium-speed mode and when shifting from the medium-speed to the low-speed mode are the same as those at the time of shifting to the high-speed mode, and the description is omitted.

FIG. 12 is a circuit diagram showing a configuration according to another embodiment of the present invention. In the figure, 2, 18, 1
9 is the same as that shown in FIG. Reference numeral 21 denotes a medium-speed forward / reverse latch signal output unit, as will be described below with reference to FIG. 19, the first, second and third frequency-divided signals (A), (B), (C) and An AND gate, an OR gate, and an inverter which receive an MMODE signal as inputs are provided. Reference numeral 22 denotes a medium-speed mode change mask signal output unit.
24 is a medium-speed forward / reverse information latch permitting unit, and includes a delay circuit 24a,
F / Fs 24b, 24c, and 24d, an AND gate, an OR gate, and an EX-OR gate.

The medium-speed forward / reverse latch signal output section 21 outputs the first, second, and third frequency-divided signals (the first, second, and third frequency-divided signals) obtained by dividing the frequency of the reference signal, as shown in FIG. A), the first defined by (B) and (C)
To the eighth section z0, z1, z2, z3, z4, z
5, z6, and z7 are defined as one cycle of the medium-speed sampling mode, the first to third sections z0 to z2 are both-side sampling of signals a and b, and the fourth to eighth sections z3-z
7 is defined as a sampling pattern for applying a voltage such that sampling is performed only on the signal a side (note that the first to eighth sections z0 to z7 are synchronized with the reference clock, Mode changes of medium speed and high speed are synchronized with the signal a), for example, as shown in FIG.
It can be implemented by a gate circuit including a gate and an OR gate.
The output M of the medium-speed forward / reverse latch signal output section 21 outputs an “L” level in a mode other than the medium speed, which is the medium speed mode.
And the timing of transition from z2 to z3 (<11 in FIG. 13).
><12>), the signal changes from “L” to “H”, and the medium-speed forward / reverse latch signal M is output.

The operation of the mask signal output section 22 when the medium speed mode is changed will be described with reference to FIG. The output (d) remains at "L" level until the falling of the signal M is detected.
That is, when the mode shifts from the other mode to the middle speed mode in the middle of z0 to z2 (section IV), the output (d) remains at “L” level because the signal M does not fall, and z
In the medium speed mode in all the sections from 0 to z2 (section V), the signal (d) becomes "H" because the M signal falls when the state shifts from z7 to z0. Thus from z0 to z
If the mode is changed to the middle speed mode in the middle of Step 2, the signal (d) = ”
Since the rise of the signal M is masked by L ", the latch signal becomes invalid, and the input (f)
Remains at "L" (timing <11>), and when the entire section from z0 to z2 is in the medium speed mode, the signal (d)
= “H”, a latch signal is output to the input (f) (timing <12>) (here, (h) is always “H”)
Is assumed).

The operation of the medium-speed forward / reverse information latch permission section 24 will be described with reference to FIG. The first half of FIG. 14 shows a case where the medium-speed forward / reverse latch permitting section 24 has normally detected normal / reverse, and the latter half of FIG. 14 shows a case where normal / reverse has not been normally detected. It should be noted that whether or not detection has been normally performed is determined by the F / F 24
b, 24c, and when the PA signal is at the “H” level, the PB signal is changed from “L” to “H” or from “H” to “H”.
When it changes to L ", it is assumed that the normal and reverse directions can be normally detected.
Q output of F / F 24d at timing <13> of 4 (h)
Changes from “L” to “H”, and the latch signal M is input (f).
(Timing <14>). F / F24b, 2
The reset signals (no) of 4c and 24d are controlled by the signal M and the signal (d), and the reset is released only during the diagonal lines as shown in FIG. That is, only when the forward / reverse is reliably detected between z0 and z2 (timing <13>),
A latch signal is generated at the input (f) (timing <14
>), The forward / reverse information is taken into the forward / reverse latch unit 18. As shown in section (VI), normal / reverse cannot be detected and signal (H) is "H".
Otherwise, no latch signal (f) is generated.

FIG. 15 is a circuit diagram showing a configuration of still another embodiment of the present invention. In the figure, reference numeral 17 denotes a latch timing generation unit; 25, a mode transition-time mask signal output unit that outputs a mask signal when a mode transition occurs;
Reference numeral 26 denotes a medium-speed forward / reverse information latch permitting unit for permitting forward / reverse latching only when forward / reverse can be normally detected during a and b both-side sampling;
Is a forward / reverse information latch unit for latching forward / reverse information. Latch timing generator 17
Can be implemented with the same circuit configuration as the decode timing generator 12 shown in FIG. 6, for example.
Let it be delayed by a. Also, the reset unit 27 is provided in FIG.
Can be implemented with the same circuit configuration as the counter reset unit 6 shown in FIG. The medium-speed forward / reverse information latch permission unit 26
The reset is released and the operation is performed only in the middle speed mode in the section from z0 to z2.

A method of capturing the forward / reverse information will be described with reference to FIGS. When the operation of the PA and PB signals in the medium speed mode is as shown in FIG.
7a signal (f) and the F / F 27a of the reset unit 27
The operation of the output signal (e) is as shown in FIG. The signal (ma) of the medium-speed forward / reverse information latch permission section 26 is <15 in FIG.
>, The reset signal is input from the signal (e), and the signal becomes “L” level. The output signal (m) of the medium-speed forward / reverse information latch permission section 26 is the input signal (m)
Rises to "H", and becomes "L" by the reset signal (e). Here, the signal (M) of the AND gate 31 becomes "H" for the overlap of the signals (F) and (MI), and the forward / reverse information is latched by the forward / reverse information latch unit 18 at the rise of the signal (MU). At timing <16> in FIG. 16, since the reciprocal information is not determined during the interval (VII),
No latch signal is generated at the output (D) of the D gate 31.

The operation of the PA and PB signals in the medium speed mode is shown in FIG.
If it is 7, since the forward / reverse is determined at timing <17><18>, a latch signal is generated at the output (M) of the AND gate 31. Since the F / F 26a holds that the input signal (MA) has become "H" at the timing <18> (the signal (MI) remains "H"), the falling edge of the PA signal is z2. AND occurs even after the transition from
Since a latch signal is generated at the output (m) of the gate, forward / reverse information can be reliably captured.

FIG. 18 shows the operation when the mode shifts. At timings <19> and <20>, a latch signal is generated in the signal (m) as in FIG. However, since the mode shifts to the high-speed mode at the timing <21>, the signal (M) is masked by the hatched portion of the output signal (M) of the mask signal output unit 25 at the time of the mode shift, and the output signal (Y) of the AND gate 32 becomes "". L ", and no forward / reverse information is taken in at the time of mode transition.

[0048]

As described above, according to the first aspect of the present invention, one cycle of the first and second signals output from the magnetic sensor is measured, and the measurement result is determined by the predetermined cycle. If this is the case, an overflow signal is output,
If the sampling signal of the magnetic sensor is switched to slow sampling and a change in the signal output of the magnetic sensor is detected,
Since control is performed to switch to fast sampling, when the rotating body is stopped or rotating very slowly, the voltage application interval of the magnetic sensor can be delayed to reduce current consumption and change the state. At the time of detection, the voltage application interval of the magnetic sensor can be increased again to minimize the counting error.

According to the second aspect of the present invention, when a state change is detected, a fast sampling signal is supplied to determine the rotation direction, and the sampling signal of the magnetic sensor is reduced at a low speed according to the cycle measurement result. Controls to medium or high speed sampling signal, and when it becomes shorter than the predetermined period, it switches to use the signal of the synthesized pulse output unit as an integrated pulse, so even if the rotation suddenly changes from the stop state to the fast rotation, it reverses Can be determined correctly, a synthesized pulse is also generated, integration can be performed accurately, the counting error can be minimized, and the signal of the forward / reverse determination & synthesized pulse output section is always integrated pulse and forward / reverse information. When used as, the output of the magnetic sensor cannot follow the rotation speed of the rotating body unless the voltage application interval of the magnetic sensor is made very fast,
Since the forward / reverse information of the forward / reverse determination unit is used only for a part of low speed and medium speed, and the signal of the combined pulse output unit is used as an integration pulse only for low speed, the voltage application interval of the magnetic sensor can be made coarse. Thus, current consumption can be reduced. In addition, since the application of the voltage on the b side is stopped in a part of the medium speed and the high speed sampling mode, the current consumption can be further reduced.

Further, according to the present invention, the normal / reverse information when switching from the low-speed sampling mode to another sampling mode or when switching from another sampling mode to the low-speed sampling mode is invalidated. Only when there is no change in the mode after the determination, the forward / reverse information is latched, and switching is made between using the forward / reverse information as it is or using the output signal from the forward / reverse information latch unit. In the case of the sampling pattern in which the voltage is applied only to the normal pattern, the reciprocal information is always invalidated. That is, when shifting from the low-speed mode to the medium-speed mode or the high-speed mode and from another mode to the low-speed mode, the rotation of the medium-speed mode is applied to the magnetic sensor at the voltage application interval of the low-speed mode. The rotation may be recognized as reverse rotation, so when shifting from the low-speed mode to another mode and from another mode to the low-speed mode, the forward / reverse information is not taken in by the signal of the mask signal output unit at the time of the low-speed mode change. The integrated value can be correctly counted. Further, in the high-speed mode, the forward / reverse cannot be determined because only the voltage on the a side is applied, so that the forward / reverse information can be prevented from being taken in by the signal of the high-speed mask signal output unit.

According to the fourth aspect of the present invention, the forward / reverse information is fetched only when the forward / reverse of the rotating body can be normally detected at the time of sampling on both the first and second signal sides in the medium speed sampling mode state. When the transition from the first and second signal-side sampling to only the first signal-side sampling state is performed, normal / reverse information is fetched, and the medium-speed sampling mode is performed from the beginning to the end of the first and second signal-side sampling sections. If not, invalidate the medium-speed forward / reverse latch signal. That is, only when the mode is the medium speed mode from the beginning of the first section z0 to the end of the third section z2 and when normal / reverse is normally detected, the fourth section z2 to the fourth section z4
Since the forward / reverse information is fetched when moving to the section z3, the forward / reverse information can be fetched reliably even at the medium speed rotation, so that the counting error can be suppressed.

According to the fifth aspect of the present invention, a latch signal is output each time one cycle of the first signal is detected in the middle-speed sampling mode, and the first and second signal-side samplings are performed. Only when forward / reverse can be normally detected at the time of, the forward / reverse information latch is enabled, and when there is a transition to the sampling mode, the forward / reverse information is masked. Reliable forward / reverse information can be captured instantaneously, and count errors can be minimized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electronic water meter according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a detailed configuration of a main part of the embodiment of FIG. 1;

FIG. 3 is a timing chart showing the operation of the embodiment of FIG. 1;

FIG. 4 is a timing chart showing the operation of the embodiment of FIG. 1;

FIG. 5 is a block diagram showing a configuration of another embodiment of the present invention.

FIG. 6 is a circuit diagram illustrating a detailed configuration of a main part of the embodiment of FIG. 5;

FIG. 7 is a circuit diagram showing a configuration of a switch used in the embodiment of FIG.

FIG. 8 is a timing chart showing the operation of the embodiment of FIG. 5;

FIG. 9 is a timing chart showing the operation of the embodiment of FIG. 5;

FIG. 10 is a block diagram showing a configuration of still another embodiment of the present invention.

FIG. 11 is a timing chart showing the operation of the embodiment of FIG. 10;

FIG. 12 is a circuit diagram showing a configuration of another embodiment of the present invention.

FIG. 13 is a timing chart showing the operation of the embodiment of FIG.

FIG. 14 is a timing chart showing the operation of the embodiment of FIG.

FIG. 15 is a circuit diagram showing a configuration of still another embodiment of the present invention.

FIG. 16 is a timing chart showing the operation of the embodiment of FIG.

FIG. 17 is a timing chart showing the operation of the embodiment in FIG. 15;

FIG. 18 is a timing chart showing the operation of the embodiment of FIG.

FIG. 19 is a timing chart showing an example of a pattern in a medium-speed sampling mode.

FIG. 20 is a block diagram showing a configuration of a conventional electronic water meter.

21 is a circuit diagram showing a detailed configuration of a block shown in FIG. 20.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 magnetic sensor 2 forward / reverse determination section & composite pulse output section 3 state change detection section 4 stop & fine flow mode control section 5 cycle measurement section 6 counter reset section 7 sampling voltage drive section 10 forward / reverse determination mode control section 11 sampling mode control Unit 12 Decode timing generation unit 16 Low-speed mode change mask signal output unit 17 Forward / reverse information latch timing generation unit 18 Forward / reverse information latch unit 20 High-speed mask signal output unit 21 Medium-speed forward / reverse latch signal output unit 22 Medium-speed mode Change-time mask signal output section 24 Medium-speed forward / reverse latch enable section

Claims (5)

[Claims] 1. A magnetic sensor for magnetically detecting the number of revolutions of a rotating body that rotates according to the amount of water used, outputs first and second signals, and outputs the first and second signals based on the first and second signals. Forward / reverse information indicating the rotation direction of the rotating body;
And an integrated water meter that outputs a combined pulse of the second signal to an integrating unit to integrate the amount of water used, and measures one cycle of the first and second signals output from the magnetic sensor. A period measuring unit that outputs an overflow signal when the measurement result is equal to or longer than a predetermined period;
A stop / fine flow mode control unit that receives the overflow signal, outputs a control signal for controlling the sampling signal of the magnetic sensor to switch to slow sampling, and sets a stop / fine flow mode, and the stop / fine flow mode When detecting a change in the signal output by the magnetic sensor in the slow sampling state of the stop / micro flow rate mode set by the control unit, a state change detection unit that outputs a control signal that controls switching to fast sampling. An electronic water meter, comprising: 2. A forward / reverse determination mode for supplying a fast sampling signal to both the first and second signals in order to determine a rotation direction of the rotating body when the state change detection unit detects a state change. A control unit, a sampling mode control unit that controls the sampling signal of the magnetic sensor to one of a low speed, a medium speed, and a high speed sampling signal according to a measurement result of the period measurement unit, and sets a corresponding sampling mode, When the measurement result of the period measuring unit is equal to or shorter than a predetermined period, a synthesized pulse switch that switches the first or second signal to the integrating unit instead of the synthesized pulse. The electronic water meter according to claim 1, wherein 3. When the sampling mode set by the sampling mode control unit is switched from the low-speed sampling mode to another sampling mode, or when the sampling mode is switched from another sampling mode to the low-speed sampling mode, the normal / inverse information is invalidated. A low-speed mode change-time mask signal output unit, a normal / reverse information latch timing generation unit for generating a timing for latching the normal / reverse information, and the forward / reverse only when there is no change in the sampling mode after the sampling mode is determined. A forward / reverse information latch unit for latching information, and forward / reverse information switching for switching between using the forward / reverse information as it is or using an output signal from the forward / reverse information latch unit as forward / reverse information to the integrating unit Set by a switch and the sampling mode control unit And a high-speed mask signal output section for always invalidating the reciprocal information when the high-speed sampling mode is a sampling pattern for applying a voltage only to the first signal side.
Electronic water meter as described. 4. The first through eighth sampling patterns in the medium-speed sampling mode are defined by first, second and third frequency-divided signals obtained by sequentially dividing a reference signal.
Is defined as one cycle of the medium-speed sampling mode,
The third to third sections are sampling on both the first and second signal sides, and the fourth to eighth sections are sampling patterns for applying a voltage such that sampling is performed only on the first signal side. When defined, medium-speed forward / reverse information latch permission to take in forward / reverse information only when forward / reverse of the rotator can be normally detected during sampling on the first and second signal sides in the middle-speed sampling mode state. A medium-speed forward / reverse latch signal output unit for capturing forward / reverse information when shifting from the first and second signal-side sampling to the first signal-side sampling state only; and the first and second If the medium-speed sampling mode is not set from the beginning to the end of both signal-side sampling sections, the medium-speed mode change mask signal output unit that invalidates the medium-speed forward / reverse latch signal Electronic water meter according to claim 2, characterized in that it has. 5. A first to eighth sampling patterns in the middle-speed sampling mode defined by first, second and third frequency-divided signals obtained by sequentially dividing a reference signal.
Is defined as one cycle of the medium-speed sampling mode,
The third to third sections are sampling on both the first and second signal sides, and the fourth to eighth sections are sampling patterns for applying a voltage such that sampling is performed only on the first signal side. When defined, a latch signal generating unit that outputs a latch signal each time one cycle of the first signal is detected in the medium-speed sampling mode state, and performs a forward / reverse operation at the time of both the first and second signal-side sampling. A medium-speed forward / reverse information latch permitting unit that permits latching of forward / reverse information only when a normal detection is possible, and a mode transition mode output unit that masks forward / reverse information when there is a transition to the sampling mode. 3. The method according to claim 2, wherein
Electronic water meter as described.