JPS61264221A - Water level measuring instrument - Google Patents

Abstract

PURPOSE:To measure the water level with a high accuracy by constituting a water level measuring instrument with a float which rises and falls in accor dance with the variation of the water level, a pulse generator which generates pulses having positive and negative polarities in accordance with this rise and fall of the float, and an up/down counter and converting the counter output to an electric signal through a converter. CONSTITUTION:A float 1 is floated on the surface of water filled in a water tank 11, and a pulse generator 20 which generates a positive or negative-polarity pulse signal 21 in accordanc with the rise or fall of the float 1 is rotated, and the generated pulse signal 21 is inputted to a water level oscillator 13. This oscillator 13 consists of a pulse counter 30, whch up-counts the signal 21 if it has the positive polarity and down-counts it if it has the negative polarity, and a converter 40 whose range is switched to 0-5m and 0-20m by an external signal 50. A unified electric signal 10 outputted from the oscillator 13 is converted to DC 4-20mA and is displayed on a display device omitted in the figure. Thus, the correct water level is obtained with one measuring instrument to reduce the cost of equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a water level measuring device, and more particularly to a water level measuring device whose measurement range can be varied.

[Conventional technology]

Water level measuring devices are used to measure various liquid levels in water tanks and various tanks. Conventionally, there has been a water level measuring device of this type as shown in FIG. In Figure 2, (1)
is the float that detects the position of the water surface, (2) is the mechanism that converts the vertical movement of the float (1) into rotational movement, (3) is the potentiometer, and (4) is the resistance of the potentiometer (3). A converter that converts the voltage corresponding to the value into a unified electric signal that is a current signal, αα is the unified electric signal, aυ is the water tank, α
is a water level transmitter.

Next, the operation of the conventional water level measuring device will be explained. The potentiometer (3) has a resistance value corresponding to the maximum value (span) of the vertical displacement (water level) of the water surface of the water tank aυ, and a voltage corresponding to the resistance that changes depending on the position of the float (1). Output. A converter (4) converts this voltage into a unified electrical signal aα and outputs it.

This unified electric signal α0) is, for example, DC4 to 20 (mA
:1, which corresponds to the preset water level range of the aquarium.

[Problem that the invention seeks to solve]

When the conventional water level measuring device having the above configuration is used, for example, to measure the water level of an inflow tank of a sewage treatment plant, a low range (for example, 0 to 5 m) is usually sufficient.

However, when it rains heavily, the water level increases, so it is necessary to use a high range (for example, 0 to 1077L). Therefore, if you want to measure the water level with a certain degree of accuracy, it is necessary to install multiple water level measuring devices for each range (for example, two low-range and high-range ones), which increases the cost. There was a problem that it took a while.

If you try to measure the water level with a single water level measuring device, you will have to use a device with a range that corresponds to the maximum water level that can be expected, and the measurement accuracy will deteriorate under normal conditions when the water level is low. There was a problem.

The present invention has been made to solve the above problems,
The purpose is to provide a water level measuring device that can measure water level with high accuracy.

[Failure to solve the problem]

Therefore, the present invention has a water level detection means for detecting the water level and a plurality of measurement ranges, and converts the water level detected by the water level detection means into a unified electric signal in the measurement range selected from the plurality of measurement ranges by an external signal. A water level measuring device fk is constructed from the converter that outputs the water level.

[Effect]

In the water level measuring device configured as described above, the water level detection means detects the water level, and the converter converts the water level detected in a measurement range selected from a plurality of ranges into a unified electric signal and outputs the same.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a water level measuring device according to the present invention. In Figure 1, (1) is a float that rises and falls according to the height of the water level in the water tank (11), and ■ is a pulse generator that generates a pulse signal QIJ of positive or negative polarity according to the rise and fall of the float (1). , (to) is a pulse counter that counts the number of pulses of the pulse signal Qυ output by the pulse generator ■, and counts up when the pulse signal is of positive polarity and counts down when it is a pulse signal of negative polarity. According to
Outputs the count value corresponding to the current water level of the water tank αυ. The float (1), the pulse generator and the pulse counter constitute water level detection means for detecting the water level of the water tank aυ. Also, (40) is 0 to 5 doors and 0
A converter having two measurement ranges A and B of ~20 m, one of the two measurement ranges is selected by an external signal (50), and the count value of the pulse counter (to) is determined by this selected range. -tDc4~20 [rIL
A] A unified electric signal in the range αIK is converted and output. Cl5) is a water level transmitter.

Next, the overall operation of the water level measuring device according to the present invention will be explained. First, the displacement of the water surface of the tank αυ is equal to the float (1
) and the pulse generator ■ input a pulse signal (211) to the 0th stage of the water level transmitter.The pulse counter ■ receives a positive pulse signal when the water surface rises, and a negative pulse signal when the water surface falls. Therefore, it counts up or down depending on the polarity of the pulse signal, and always maintains a count value corresponding to the current water level.

The converter (40) has two measurement ranges of 10,000 selected by an external signal (50), and depending on the selected range, the count value of the pulse counter (to) is converted into a uniform electric current corresponding to the current water level of the water tank aυ. Convert to signal aα and output.For example, if A range (0 to 5m) is selected,
The water level corresponding to the count value of the pulse counter (to) is 2
．． When the distance is 5 m, a unified electrical signal of 12 mA DC is output.

In this example, IJ, which is a pulse signal of positive and negative polarity, is used as information indicating the displacement of the water surface. However, if a signal to distinguish between rising and falling water level is input separately, a pulse signal of positive and negative polarity can be used. There is no necessary Vi.

Further, the pulse signal Q11 may be a digital signal directly indicating the displacement of the water surface.

〔Effect of the invention〕

As explained above, according to the present invention, the water level detection means for detecting the water level and a plurality of measurement ranges are provided, one measurement range is selected from the plurality of measurement ranges by an external signal, and the selected range is selected. By configuring the water level measuring device with a converter that converts the water level detected by the water level detection means into a unified electrical signal, a highly accurate unified electrical signal can be generated over a relatively full span in a measurement range that corresponds to the water level. Obtainable.

Furthermore, since a single water level measuring device selects an appropriate measurement range from a plurality of measuring ranges, the overall equipment cost is lower than in the case of using a plurality of water level measuring devices.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a water level measuring device according to the present invention, and FIG. 2 is a schematic diagram of a conventional water level measuring device. In the figure, 1 is a float, 10 is a unified electric signal, and 11
water tank, 13 is a water level transmitter, 20#-t pulse generator,
21 is a pulse signal, 60 is a pulse counter, 40 is a converter, and 50 is an external signal. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (2)

[Claims] (1) It has a water level detection means for detecting the water level and a plurality of measurement ranges, and converts the water level detected by the water level detection means into a unified electric signal in a measurement range selected from the plurality of measurement ranges by an external signal. A water level measuring device characterized by comprising: a converter for outputting a water level. (2) The water level detection means includes a float that rises and falls according to the height of the water level, a pulse generator that generates pulses of positive and negative polarity by raising and lowering the float, and a pulse generator that generates pulses of positive and negative polarity according to the polarity of the pulses of the pulse generator. The water level measuring device according to claim 1, comprising a counter that counts up or down the pulse.