WO2016029837A1

WO2016029837A1 - Ultra-low power consumption magnetic induction type floater water level sensor and signal processing method

Info

Publication number: WO2016029837A1
Application number: PCT/CN2015/087994
Authority: WO
Inventors: 熊光亚; 黄磊; 李延军; 薛升宁
Original assignee: 国网电力科学研究院; 南京南瑞集团公司
Priority date: 2014-08-25
Filing date: 2015-08-25
Publication date: 2016-03-03
Also published as: CN104236677A

Abstract

An ultra-low power consumption magnetic induction type floater water level sensor comprises an encoder, a driving gear set, a water gauge range wheel (2), a counterweight (3), a steel wire rope(4) and a floater (5). Three magnetic induction reed pipes (7) in 120-degree angular difference are mounted on a fixed code tray of the encoder (6), two signal wires are led from each reed pipe (7), and a magnet (8) is mounted at the top end of a rotating arm of the encoder (9). When the magnet (8) passes by the reed pipes (7), the two output signal wires of the reed pipes (7) are enabled to generate low level, and a data collector is roused and the logic state of the signal wires is compared, thereby acquiring a level condition. And a signal processing method using the water level sensor described above.

Description

Ultra-low power magnetic induction float water level sensor and signal processing method

Technical field

The invention relates to an ultra-low power magnetic induction float water level sensor and a signal processing method, and belongs to the field of hydrology and water purification automation.

Background technique

In the field of hydrology and water purification automation, hydrological telemetry stations are used to collect and remotely transmit original hydrological information, including rainfall, water level, and flow. The hydrological telemetry station generally consists of various sensors, data collectors, remote communication devices, and power devices. The sensor is responsible for converting the hydrological information into an electrical signal, and the data collector is responsible for collecting the electrical signals and converting them into actual physical quantity values, and transmitting the data to the data center through the remote communication device for processing and analysis by the data center.

The sensors currently used for water level measurement can be divided into two types according to the way of data output:

Pure passive sensor: This kind of water level sensor measurement needs to be initiated by the data collector. It can't initiate measurement by itself. The sensor can only sample and convert the data into electricity after receiving the measurement command or power excitation from the data collector. The signal is output to the data collector. Most of the water level sensors currently used in hydrological telemetry stations are passive sensors.

Active sensor: This type of sensor can initiate water level measurement and can upload the measured data to the data collector actively. It can also receive the command sent by the data collector to initiate measurement and return the measurement result to the data collector.

Hydrological telemetry stations are often installed in remote areas. There are basically no AC power supply conditions on the site. The equipment is generally powered by batteries and solar cells. To ensure that the equipment works in the sunshine-free environment for as long as possible, the operating power consumption of the equipment should be as low as possible. In practical applications, the data collector of the hydrological telemetry station generally initiates sampling of the water level sensor at a fixed time interval, collects the data and sends it to the data center through the remote channel, and then enters the sleep state to reduce its own work. Consumption, until the next sampling time comes, then start work. If the hydrological telemetry station uses a passive water level sensor, then the timing sampling mode of operation also determines that between the two sampling moments, if the water level changes greatly, the process of this change cannot be perceived and sampled because The data collector is in a sleep state during this time period. However, when the water level is suddenly changed, it may cause huge disasters. For example, summer heavy rains can cause mountain floods to rise in a short period of time and cause mountain flood disasters. If the hydrological telemetry station uses an active sensor, the sensor is always in working state, which will lead to an increase in the overall power consumption of the device. In the case of continuous rainy weather and insufficient solar power supply, the battery can support the device to work continuously for a limited time. Therefore, how to reduce the power consumption of the device under the premise of capturing the water level change in real time is always in the wild. A problem in water level measurement under AC power conditions.

At present, in some key hydrological telemetry stations, in order to capture water level information in real time, photoelectrically encoded float sensors are generally used. Compared with sensors using other measurement principles (mainly pressure water level sensor, radar water level sensor, ultrasonic water level sensor, laser water level sensor), this type of sensor is the only active sensor that can contain no processor. It is also the lowest of all active sensors. The photoelectric sensor has a set of optical switching devices. The measuring principle is that the rising or falling of the water level will drive the code wheel to rotate, and the signal outputted by the optical switching device will change accordingly. At the same time, a photoelectric conversion device converts the optical signal into The electric pulse signal, which can wake up the data collector of the back end from the sleep state and start the water level collection. The float type water level gauge needs to provide external power supply during operation. The optical switch device is always in working state, and the average power consumption is about 100mw. For the hydrological telemetry station in the field, a large-capacity battery is needed to ensure continuous rainy conditions. The continuous working hours of the equipment.

In the absence of AC power supply in the field, in order to reduce the overall operating power consumption of the hydrological telemetry station equipment, the data collector generally does not run at full speed, but starts sensor acquisition at a certain time interval, and enters sleep after completing the acquisition and remote communication tasks. Status to save power. At present, most of the water level sensors used in hydrological telemetry stations are passive sensors. When the data collector is in a dormant state, water level data cannot be collected, which may miss important water level changes. At present, the more popular photoelectric coded float water level sensor can actively measure the water level in real time, but needs to run at full speed. By continuously transmitting the light signal to sense the water level change, the power consumption is too large, and the hydrological telemetry station installed in the field needs to be configured with a larger capacity. The battery is used to ensure that the equipment can continue to work for a long time under continuous rainy conditions. However, hydrological telemetry stations are often in areas with traffic conditions, and large-capacity batteries are not convenient for transportation and carrying.

Summary of the invention

The invention provides an ultra-low power magnetic induction float water level sensor and a signal processing method, which can not only sense the water level change in real time, but also convert the water level change into an electric pulse signal and transmit it to the data collector, so that the collector does not miss when sleeping. The important water level change process; and the sensor's usual maximum power consumption is only about 1/40 of the photoelectric coded float type water level sensor, and can operate at zero power consumption in most states. Therefore, the sensor is especially suitable for real-time water level collection in the field without AC power supply.

In order to achieve the above object, the technical solution adopted by the present invention is as follows:

An ultra-low power magnetic induction float water level sensor comprising an encoder, a transmission gear set, a water level meter wheel, a counterweight, a wire rope and a float, the encoder and the transmission gear set being mounted on a casing of the float water level sensor, The wire rope is mounted on the water level meter wheel, one end of the wire rope is a counterweight, and the other end is a float;

The encoder is composed of a fixed code wheel and a rotating arm. Three fixed magnetic reed switches with an angle difference of 120 degrees are mounted on the fixed code wheel, and each of the magnetic induction reed switches leads two signal lines. Pumping from each of the magnetic induction reed switches One signal line is connected and connected together as a common end;

The rotating arm and the fixed code wheel are mounted in parallel, and a magnet is mounted on the top end of the rotating arm to rotate with the rotating arm;

The transmission gear set comprises two sets of transmission gears and a transmission shaft, and the two transmission gears are meshed, wherein one transmission shaft is coaxial with the rotating arm, and the other transmission shaft and the water level meter wheel are coaxial; when the water level rises or falls The steel wire rope drives the water level meter wheel to rotate, and the water level meter wheel drives the transmission gear on the same transmission shaft to rotate, and the transmission gear wheel drives the other transmission gear coaxial with the rotating arm to drive the rotating arm to rotate;

The magnetic induction reed switch is connected as a common signal line to the digital signal ground of the data acquisition device of the hydrological telemetry station, and the other three signal lines are connected to the digital input port of the data collector of the hydrological telemetry station.

The aforementioned digital input ports of the data collector are pulled up to a high level using a resistor, and these digital input ports support level interrupts.

The aforementioned resistance value is selected between 10K and 100K.

The signal processing method of the ultra-low power magnetic induction float water level sensor comprises the following steps:

1) Define the binary logic state representation of the output signal of the magnetic induction reed switch, and obtain the binary logic state combination of the three magnetic induction reed switches. When the magnetic induction reed switch is closed, the output signal is represented by binary 0. Expressed in binary 1;

2) Defining the rotation of the rotating arm clockwise indicates that the water level drops, and counterclockwise rotation indicates that the water level rises;

3) The data collector of the hydrological telemetry station is normally in a dormant state. When the water level rises or falls, the rotating arm rotates counterclockwise or clockwise, thereby driving the magnet to rotate together;

4) When the magnet passes through any magnetic induction reed switch, it will cause the reed inside the magnetic induction reed switch to be sucked, thereby causing the two output signal lines of the magnetic induction reed switch to be in a short-circuit state and output a low level;

5) The low level signal causes an interrupt on the digital input port corresponding to the processor of the data collector to wake the data collector from the sleep state;

6) The data collector reads the binary logic state of the current three magnetic induction reed switch output signals, and compares with the previous logic state to determine whether the rotating arm moves clockwise or counterclockwise, thereby determining that the water level is rising by one resolution unit. Still drop one resolution unit.

The aforementioned water level sensor resolution is calculated as:

The amplitude of the water level change generated by the adjacent two water level signals is the resolution of the water level sensor. Each time the dummy design wheel rotates, the encoder rotating arm rotates N times, and the water level meter wheel has a circumference of L, and the water level sensor distinguishes The rate is R, then R = L / (N × 3).

The invention does not need to supply power separately, and completely relies on the rotation of the water level wheel to trigger the magnetic induction reed switch to generate the electric pulse signal wake-up number. According to the collector, the current consumption is only on a pull-up resistor of the back-end signal processing circuit. Therefore, the present invention is superior to the photoelectric-coded active sensor in power consumption level, and is suitable for the field without AC power supply. Used for water level measurement. The measuring principle adopted by the invention not only can capture the water level change in real time, but also greatly reduces the running power consumption of the device, and enhances the battery life capability of the device under the condition of no AC power supply in the field.

DRAWINGS

1 is a schematic structural view of a float water level sensor of the present invention;

2 is a schematic diagram showing the structure and signal line of an encoder fixed code disc in the sensor of the present invention;

Figure 3 is a schematic view showing the position of the encoder rotating arm and the fixed code wheel in the sensor of the present invention.

detailed description

The ultra low power consumption magnetic inductive float water level sensor of the present invention is composed of an encoder, a transmission gear set, a water level meter wheel 2, a counterweight 3, a wire rope 4 and a float 5, wherein the encoder and the transmission gear are as shown in FIG. The group is mounted on the outer casing 1 of the float water level sensor, and the wire rope 4 is mounted on the water level meter wheel 2, one end of which is a counterweight 3 and the other end is a float 5. The transmission gear set includes two sets of transmission gears and a transmission shaft. The two transmission gears mesh with each other. One of the transmission shafts is coaxial with the rotating arm, and the other transmission shaft and the water level metering wheel are coaxial; when the water level rises or falls, The wire rope 4 drives the water level meter wheel 2 to rotate, and the water level meter wheel 2 drives the transmission gear on the same transmission shaft to rotate, and the transmission gear wheel drives the other transmission gear coaxial with the rotating arm to drive the rotating arm to rotate.

The encoder is the core component of the sensor of the present invention and consists of a fixed code wheel and a rotating arm.

As shown in Fig. 2, three fixed magnetic reed pipes with a difference of 120 degrees are mounted on the fixed code disc. Each reed switch leads two signal lines, and one signal line is extracted from each reed switch. Together as the common terminal G, the remaining signal lines are recorded as A, B, and C, respectively. When the reed switch is subjected to magnetic attraction, the reed inside the reed switch is attracted by the magnetic field and shorts the two signal lines in the reed switch, and the two signal lines are normally in an open state.

As shown in FIG. 3, the rotating arm 9 is a component which can be moved in a circular motion, and is mounted in parallel with the fixed code wheel 6. The rotating arm 9 is driven by a coaxial transmission gear thereof. When the measured water level fluctuates, the transmission gear will The rotating arm 9 is rotated. A magnet 8 is mounted on the top end of the rotating arm 9, and the magnet 8 rotates with the rotating arm 9. When the magnet 8 passes through the magnetic induction reed switch 7, the reed inside the magnetic induction reed tube 7 is attracted, thereby causing the magnetic induction reed. The two output signal lines of the tube are in a short-circuit state and output a low level.

The signal processing method of the present invention is:

First, define the binary logic state representation of the output signal of the magnetic induction reed switch. When the reed switch is closed, the output signal is represented by binary 0, and when it is not in the closed state, it is represented by binary 1, then the logic state of the three reed switches. The combination is represented by binary logic, and there are several states as shown in Table 1.

Table 1 Reed Switch Logic Status Table

AA	BB	CC
AA	BB	CC	11	11	00
00	11	11	11	11	00
00	11	11	11	00	11
11	11	11	11	00	11

Secondly, defining the clockwise rotation of the rotating arm indicates that the water level drops, and counterclockwise rotation indicates that the water level rises. In this way, it is possible to determine whether the water level rises or falls by comparing the front and rear states of the encoder reed switch. For example, suppose the current state of the encoder is 110. According to FIG. 2 and Table 1, it can be inferred that if the next state is 101, it means that the water level drops; if it is 011, it means that the water level rises.

Then, the logic state of the signal line is read by the data collector, and the water level condition is judged.

Similar to the photoelectrically encoded float water level gauge, the float water level sensor of the present invention obtains an incremental signal from the encoder output, so the data collector of the hydrological telemetry station needs to design corresponding signal processing circuits and programs for normal use. As shown in Figure 2, the water level sensor has a total of four signal lines, of which A, B, C should be connected to the digital input port of the data collector, and these ports should use resistors (resistance values are selected from 10K to 100K) The pull-up is high, and these digital input ports need to support the level interrupt function, while the common terminal is connected to the digital signal ground of the data collector.

The data acquisition device of the hydrological telemetry station is usually in a dormant state. When the water level rises or falls, the common gear of the rotating arm drives the rotating arm to rotate counterclockwise or clockwise, and the rotating arm drives the magnet to rotate together, when the magnet passes any magnetic induction. When the reed switch is used, the reed in the magnetic induction reed switch will be attracted, so that the corresponding signal line outputs a low level, and the low level signal causes a corresponding digital input port of the processor of the data collector to generate a Interrupt, wake the data collector from sleep. The data collector reads the binary logic state of the current three magnetic induction reed switch output signals, and compares with the previous logic state to determine whether the rotating arm moves clockwise or counterclockwise, and then the water level rises by one resolution unit or one time. Resolution unit.

Wherein, the calculation method of the water level sensor resolution is

The amplitude of the water level change generated by the adjacent two water level signals is the resolution of the water level sensor. Each time the dummy design wheel rotates, the encoder rotating arm rotates N times, and the water level meter wheel has a circumference of L, and the water level sensor distinguishes Rate is R, then

R=L/(N×3)

For example, if the water gauge wheel has a circumference of 48 cm and N=16, the water level resolution is 1 cm.

The three signal lines connected to the digital input port of the data collector of the present invention need to be pulled up to a high level by using a resistor of at least 10K but not more than 100K, and the logic state of the signal line output of the water level gauge is 4th as shown in Table 1. In this case, since the input impedance of the port is generally M-ohm, the current consumed is almost negligible. When the logic state of the water level signal line output is other conditions as shown in Table 1, only one of the signal lines outputs a low level, which will generate a current of several hundred μA on the pull-up resistor, according to the processor. The supply voltage is 5V, the pull-up resistor is 10K, and the power consumption is only 2.5mW.

Claims

An ultra-low power magnetic induction float water level sensor, comprising: an encoder, a transmission gear set, a water level meter wheel, a counterweight, a wire rope and a float, the encoder and the transmission gear set being mounted on the float water level sensor a casing, the wire rope is mounted on a water level meter wheel, one end of the wire rope is a counterweight, and the other end is a float;

The encoder is composed of a fixed code wheel and a rotating arm. Three fixed magnetic reed switches with an angle difference of 120 degrees are mounted on the fixed code wheel, and each of the magnetic induction reed switches leads two signal lines. Extracting one signal line from each magnetic induction reed switch and connecting them together as a common end;

The rotating arm and the fixed code wheel are mounted in parallel, and a magnet is mounted on the top end of the rotating arm to rotate with the rotating arm;

The transmission gear set comprises two sets of transmission gears and a transmission shaft, and the two transmission gears are meshed, wherein one transmission shaft is coaxial with the rotating arm, and the other transmission shaft and the water level meter wheel are coaxial; when the water level rises or falls The steel wire rope drives the water level meter wheel to rotate, and the water level meter wheel drives the transmission gear on the same transmission shaft to rotate, and the transmission gear wheel drives the other transmission gear coaxial with the rotating arm to drive the rotating arm to rotate;

The magnetic induction reed switch is connected as a common signal line to the digital signal ground of the data acquisition device of the hydrological telemetry station, and the other three signal lines are connected to the digital input port of the data collector of the hydrological telemetry station.
The ultra low power consumption magnetic inductive float water level sensor according to claim 1, wherein the digital input port of the data collector is pulled up to a high level using a resistor, and the digital input port supports the electric power. Flat interrupt.
The ultra low power consumption magnetic inductive float water level sensor according to claim 2, wherein the resistance value is selected between 10K and 100K.
The signal processing method for an ultra low power consumption magnetic inductive float water level sensor according to any one of claims 1 to 3, comprising the steps of:

1) Define the binary logic state representation of the output signal of the magnetic induction reed switch, and obtain the binary logic state combination of the three magnetic induction reed switches. When the magnetic induction reed switch is closed, the output signal is represented by binary 0. Expressed in binary 1;

2) Defining the rotation of the rotating arm clockwise indicates that the water level drops, and counterclockwise rotation indicates that the water level rises;

3) The data collector of the hydrological telemetry station is normally in a dormant state. When the water level rises or falls, the rotating arm rotates counterclockwise or clockwise, thereby driving the magnet to rotate together;

4) When the magnet passes through any magnetic induction reed switch, it will cause the reed inside the magnetic induction reed switch to be sucked, thereby causing the two output signal lines of the magnetic induction reed switch to be in a short-circuit state and output a low level;

5) The low level signal causes an interrupt to be generated on the digital input port corresponding to the processor of the data collector, and the data is The collector wakes up from sleep;

6) The data collector reads the binary logic state of the current three magnetic induction reed switch output signals, and compares with the previous logic state to determine whether the rotating arm moves clockwise or counterclockwise, thereby determining that the water level is rising by one resolution unit. Still drop one resolution unit.
The signal processing method according to claim 4, wherein the calculation method of the water level sensor resolution is:

The amplitude of the water level change generated by the adjacent two water level signals is the resolution of the water level sensor. Each time the dummy design wheel rotates, the encoder rotating arm rotates N times, and the water level meter wheel has a circumference of L, and the water level sensor distinguishes The rate is R, then R = L / (N × 3).