JPH05172572A - Electronic water depth meter - Google Patents

Abstract

PURPOSE:To enable depressurization stop and surfacing in safe activity available time and improve safety in diving by calculating the safe activity available time taking the time for the depressurization stop and surfacing into account and dividing following to this. CONSTITUTION:In a pressure sensor 21, gas pressure of a bomb 20 is introduced and sensor 21 detects the pressure of the bomb 20 and outputs to an amplifier circuit 22. The circuit 22 amplifies the detected signal input from the sensor 21 and outputs to an A/D conversion circuit 23. The circuit 23 converts the analog detection signal input from the circuit 22 to digital signal and outputs to a CPU14. The CPU14 calculates the diving available time based on the detection signal. Also, the CPU14 calculates a safe activity available time using the diving available time, water depth and diving time, depressurization stop depth, depressurization stop time and standard surfacing velocity. The calculated safe activity time is indicated on a display 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic water depth gauge, and more particularly to an electronic water depth gauge that informs a safe activity time in consideration of decompression stop time and ascent time during diving.

[0002]

Decompression sickness is a problem when diving deep into water. Therefore, an electronic water depth gauge has been conventionally devised, and this conventional electronic water depth gauge generally displays a floating method for preventing decompression sickness when ascending after diving. For example, the conventional electronic depth gauge generally uses a decompression table created by the US Navy, etc., and depending on the depth of water and its retention time, the decompression depth required for ascent (the depth of retention for decompression stop) And decompression stop time (time to stay at the specified decompression depth) is calculated and displayed on the display. Therefore, when diving, the diver stops ascending when it reaches the decompression depth according to the display of the electronic depth gauge when ascending, and stops at that depth for the time required for decompression (decompression stop time). To reduce the pressure. By performing this ascending method according to the decompression stop depth and the decompression stop time displayed according to the diving depth and the residence time, decompression sickness can be prevented. Further, in the conventional electronic depth gauge, the remaining diving time is calculated from the residual pressure of the gas cylinder, and the calculated diving time is displayed and output on the display.

[0003]

However, in such a conventional electronic water depth gauge, since the remaining diving time is calculated and displayed only from the residual pressure of the gas cylinder, the decompression diving is performed. When is not necessary, the dive time becomes the actual dive time as it is, but when diving where decompression diving is required, the time required for decompression stop is not considered in the conventional dive time,
There is a gap between the actual dive time and the dive time displayed on the display. As a result, if a dive activity is performed according to the dive time displayed on the display, there is a problem that the time for decompression stop becomes insufficient and safe diving cannot be performed. Therefore,
The present invention improves the safety of diving by calculating the active time in consideration of the decompression stop time and the time required for ascent, and matching the active time with the actual time of diving activity. It is an object.

[0004]

In order to achieve the above object, the invention according to claim 1 stores a safety limit amount for storing a safety allowable limit amount when a partial pressure of an inert gas in a tissue of a human body during diving is elevated. Storage means, water depth detection means for detecting water depth, timing means for timing the residence time for each water depth, and the safety limit amount storage means based on the detection results of the water depth detection means and the timing results of the timing means. Decompression condition setting means for setting decompression conditions required for ascent from the stored safe allowable limit amount, diving possible time calculating means for calculating diving possible time from the amount of gas used for diving, and calculation of the diving possible time calculating means A safe activity possible time calculating means for calculating a safe activity possible time based on the result and the setting result of the decompression condition setting means, and a calculation result of the safe activity possible time calculating means in a predetermined output form. It is characterized by comprising an output means for outputting. In this case, for example, as described in claim 2, the decompression condition setting means sets the decompression stop water depth and the decompression stop time, and the safe activity possible time calculating means calculates the diving possible time calculating means. The safety action possible time is calculated by subtracting the decompression stop time from the dive possible time, and as described in claim 3, the decompression condition setting means sets the decompression stop water depth and the decompression stop time, The safe activity possible time calculating means floats from the diving possible time calculated by the diving possible time calculating means to the decompression stop time and the current water depth to the decompression stop water depth at a predetermined floating speed and from the decompression stop water depth to the water surface. The ascentable time for safety activity is calculated by subtracting the ascent time required for.
Further, as described in claim 4, when the decompression condition setting means sets a decompression stop water depth and a decompression stop time, and the safety activity possible time calculating means does not require decompression stop, the diving possible time. The safe activity possible time is calculated by subtracting the levitation time required to ascend to the water surface from the current water depth at a predetermined levitation speed from the dive time calculated by the calculation means, and when decompression stop is required, the diving is performed. From the dive possible time calculated by the possible time calculating means, the decompression stop time and the current water depth from the decompression stop water depth to the decompression stop water depth at a predetermined floating speed and the floating time required to ascend from the decompression stop water depth to the water surface The safe activity time is calculated. The inert gas in the tissue is, for example, nitrogen gas as described in claim 5, and the output means is display output means as described in claim 4, for example.

[0005]

In the present invention, the safe allowable limit amount when the partial pressure of the inert gas (for example, nitrogen gas) in the tissue of the human body at the time of diving is floated is stored in the safe limit amount storage means, and the water depth detection means stores the water depth. To detect. Further, the time measuring means measures the residence time for each water depth, and the depressurization condition setting means stores the safety stored in the safety limit amount storage means based on the detection result of the water depth detecting means and the time measuring result of the time measuring means. From the allowable limit amount, set the decompression condition required for ascent. Further, the possible diving time calculation means calculates the possible diving time from the amount of gas used for diving. Based on the calculation result of the dive possible time calculating means and the setting result of the pressure reducing condition setting means, the safe activity possible time calculating means calculates the safe activity possible time. In this case, the decompression condition setting means sets the decompression stop water depth and the decompression stop time, and the safety activity possible time calculation means subtracts the decompression stop time from the diving possible time calculated by the diving possible time calculating means. Calculate the safety activity possible time. Further, the decompression condition setting means sets a decompression stop water depth and a decompression stop time, and the safety activity possible time calculating means calculates the decompression stop time and a predetermined ascent from the diving possible time calculated by the diving possible time calculating means. The safe actionable time is calculated by subtracting the levitation time required to ascend from the present water depth to the decompression stop water depth and from the decompression stop water depth to the water surface at a speed. Further, the decompression condition setting means sets the decompression stop water depth and the decompression stop time,
When the safety activity possible time calculating means does not require a decompression stop, the safety activity possible time is calculated by subtracting the levitation time required to ascend to the water surface at a predetermined levitation speed from the current water depth, and the decompression stop is performed. When it is necessary to float from the current dive depth to the decompression stop water depth and from the decompression stop water depth to the water surface from the diving possible time calculated by the diving possible time calculating means to the decompression stop time and a predetermined floating speed. The ascent time required for safety activity is calculated by subtracting the ascent time required for. The calculation result of the safe activity time calculating means is output by the output means in a predetermined output form, for example, is displayed and output. Therefore, even when decompression diving is required for diving,
It is possible to calculate and output the available safety activity time in consideration of the time required for decompression stop and ascent. As a result, by diving according to the safe activity time that is output during diving, decompression stop and ascent can be performed within the safe activity time, and safety during diving can be improved.

[0006]

EXAMPLES The present invention will be specifically described below based on examples. 1 to 6 are views showing an embodiment of an electronic water depth gauge according to the present invention. 1 and 2 are external views of the electronic water depth gauge 1. The electronic water depth gauge 1 is provided with a display unit 3 and various switches 4, 5 and 6 on a body case 2 thereof.

As the display section 3, for example, a liquid crystal display device is used, and a display according to various mode settings is performed. Regarding the display contents of the display unit 3 in FIGS. 1 and 2,
It will be described later.

The switches 4, 5 and 6 are used to switch between various operation modes (for example, a clock mode and a water depth meter mode), start / stop instructions for starting measurement in the water depth meter mode, and switch or correct display contents in various modes. Used to do etc.

FIG. 3 is a circuit block diagram of the electronic water depth gauge 1. The electronic water depth gauge 1 includes an oscillation circuit 11 and a frequency dividing circuit 1.
2, total clock circuit 13, CPU (Central Processing U
nit) 14, ROM (Read Only Memory) 15, RAM (R
andom Access Memory) 16, pressure sensor 17, amplification circuit 18, A / D conversion circuit 19, cylinder 20, pressure sensor 2
1, amplifier circuit 22, A / D conversion circuit 23, switch unit 2
4, a display drive circuit 25 and a display unit 3.

The oscillator circuit 11 is a so-called crystal oscillator circuit composed of a crystal, a resistor, a capacitor, etc., and generates an original clock signal of a constant frequency.

The frequency dividing circuit 12 is formed by, for example, combining several stages of binary counters,
The original clock signal input from the oscillator circuit 11 is frequency-divided to generate a reference clock signal of 1 Hz that can be used as a reference signal for a clock, and the reference clock signal is output to the clock counting circuit 13. The clock counting circuit 13 clocks the current time and the elapsed time from the start of the dive according to the reference clock signal from the frequency dividing circuit 12, and outputs the clock to the CPU 14, and the CPU 14 receives the input from the clock counting circuit 13. The display drive circuit 21 is driven based on the measured time data to display and output the current time, the elapsed time from the start of the dive, and the like.

The ROM 15 stores a program as the electronic water depth gauge 1 and various other programs required for mode processing, in particular, a program for calculating a safety activity time and the like. The safe allowable limit amount during floating of the inert gas partial pressure (for example, nitrogen gas partial pressure) is stored. As the safety allowable limit amount stored in the ROM 15, for example, a decompression table of the US Navy is stored. The half-saturation time and the M value are set in this decompression table, and the half-saturation time is the time until the saturation amount of the inert gas in the human body tissue reaches 50%,
The M value is the safe allowable partial pressure of inert gas, that is, the maximum allowable supersaturation pressure within the specified floating speed, no matter how long the inert gas dissolves into the tissue of each half-saturation time of the human body. It can be regarded as an allowable limit amount. Therefore, the ROM 15 functions as a safety limit amount storage unit that stores the safety allowable limit amount when the human body is floating. If this value is exceeded, it must be stopped (decompression stop) until the partial pressure of the inert gas in the body falls below the M value at a predetermined water depth, and it is not allowed to ascend until then.

The RAM 16 is used as a work memory and also stores various data at the time of diving as diving record data. That is, various data areas are formed in the RAM 16 as shown in FIG. 4, and each data storage area of the RAM 16 has a diving time T, a half saturation time H, a safety factor K, a partial nitrogen pressure Q in the body, Remaining available time Tb calculated from the previous partial nitrogen pressure P in the body, nitrogen partial pressure N of respiratory gas, cylinder pressure, no-decompression diving time Tm, decompression stop time Tg,
The decompression stop depth Dg, remaining safe activity time Ts, accumulated decompression stop time Tr, and the like are stored. Here, the remaining workable time Tb is the time until the gas in the cylinder 20 is exhausted, and the remaining safe workable time Ts is the time obtained by subtracting the time required for decompression stop or ascent from the remaining workable time Tb. Is.

The CPU 14 controls each part of the electronic water depth gauge 1 according to the program in the ROM 15, and performs various processing as the electronic water depth gauge 1, for example, calculation processing of a dive time based on an input from the total clock circuit 13. Sensor 17 described later
Calculation processing of the dive depth based on the signal from, the safety activity time calculation / display processing, processing as a clock, etc. are performed.

The pressure sensor 17 is composed of a piezoelectric element or the like, detects environmental pressure, particularly water pressure, and outputs the detection result to the amplifier circuit 18. The amplifier circuit 18 includes a pressure sensor 17
The detection signal input from the A / D conversion circuit 19 is amplified.
Output to. The A / D conversion circuit 19 digitally converts the analog detection signal input from the amplification circuit 18, and C
Output to PU14. Further, the CPU 14 calculates the water depth based on this detection signal, and calculates the in-vivo nitrogen partial pressure for each of a plurality of tissue parts of the human body based on the calculated water depth and the residence time. The CPU 14 calculates the calculated nitrogen partial pressure in the body and R
It is judged from the decompression table stored in the OM 15 whether the decompression stop water depth is necessary, and if necessary, the decompression stop water depth and the decompression stop time are calculated.

The cylinder 20 is filled with a gas necessary for diving, for example, oxygen gas, and the diver performs diving using the gas in the cylinder 20.

The gas pressure of the cylinder 20 is introduced into the pressure sensor 21, and the pressure sensor 21 uses the cylinder 20.
The pressure is detected and output to the amplifier circuit 22. The amplifier circuit 22 amplifies the detection signal input from the pressure sensor 21 and outputs it to the A / D conversion circuit 23. A / D conversion circuit 2
3 digital-converts the analog detection signal input from the amplifier circuit 22 and outputs it to the CPU 14. Also, C
The PU 14 calculates the diving possible time based on this detection signal. Further, as will be described later, the CPU 14 calculates the safety activity time from the diving possible time, the water depth, the diving time, the decompression stop depth, the decompression stop time, and the standard ascending speed. The CPU 14 also causes the display unit 3 to display and output the calculated safety activity time. Therefore, the CPU
Reference numeral 14 functions as a possible diving time calculating means for calculating a possible diving time from the amount of gas used for diving.

The switch section 24 includes the various switches 4,
5 and 6 are collectively referred to, and the CPU 14 detects the operation state of the switch section 24 and performs a process corresponding to the operation of the switch section 20.

The display drive circuit 25 is driven under the control of the CPU 14 to drive the display unit 3 according to the display data input from the CPU 14. By driving the display drive circuit 25, various data are displayed on the display unit 3.

Next, the operation will be described. In the following description of the action, for simplicity, the case where the inert gas is only nitrogen will be described, but the present invention is not limited to nitrogen, but affects human tissues during diving, resulting in decompression sickness. It can be applied to general inert gas which is generated.

When diving, the partial pressure of nitrogen in human tissue of the diver generally increases as the diving depth increases. That is, when staying under a predetermined water pressure, the nitrogen partial pressure in the human body tissue gradually increases as the staying time elapses, and is saturated to the body nitrogen partial pressure corresponding to the water pressure. Therefore, if diving continues at a depth deeper than the predetermined water depth, the nitrogen partial pressure in the body increases, and if the nitrogen partial pressure in the body exceeds a predetermined amount, it is necessary to stop the decompression. The safe activity time depends on whether or not this decompression stop is required. In other words, the time required for decompression is not the time that can actually be used, but the time that must be used for safety. It is necessary to subtract the time required for the activity from the available time.

Therefore, in this embodiment, as shown in FIG. 5, when diving through the diving route X1, the remaining safety activity time Ts at the time T0 is as follows because the water depth A is the water depth that does not require decompression stop. The remaining activity time Tb is adopted as it is, but when diving to the water depth B and diving on the diving route X2 requiring the decompression stop at the water depth C, the time T0
The remaining safety activity time Ts is calculated as the remaining safety activity time Ts by subtracting the decompression stop time Tg from the remaining activity time Tb.

That is, when the water depth meter mode is set and the start switch is turned on, first, as shown in FIG. 6, initial processing is performed to initialize various registers and the like (step S1), and diving is started. Then, the measurement of the diving time is started, and the water pressure and the residual pressure of the cylinder 20 are detected by the pressure sensor 17 and the pressure sensor 21 (step S2). Based on the detection result, the water depth, the nitrogen partial pressure N of the breathing gas, and the remaining activity time Tb are calculated (step S3). The nitrogen partial pressure N of the breathing gas is calculated by the following equation, and the water depth is calculated by the water depth calculation method that has been conventionally performed by a water depth meter. N = 0.79 × water pressure (1)

Next, the internal nitrogen partial pressure Q of this time is calculated (step S4). The body nitrogen partial pressure Q at this time is calculated by the following equation. Q = P + (N−P) × (1−0.5 ^{(TIM / H)} ) (2) where P is the nitrogen partial pressure before T time (minutes), that is, the previous partial nitrogen pressure in the body. (Bar), N is the nitrogen partial pressure (bar) of the breathing gas, and H is the half saturation time (min). When the present internal nitrogen partial pressure Q is calculated by the above equation (2), the present internal nitrogen partial pressure Q is compared with the safe allowable limit amount M10 stored in the ROM 15, and the present internal nitrogen partial pressure Q is calculated. Checks whether the safety allowable limit amount M10 is exceeded (step S5). The safety allowable limit amount M10 is a value that requires decompression stop at a water depth of 10 feet.

This time, the nitrogen partial pressure Q in the body is the safe allowable limit amount M.
When it is smaller than 10, the no-decompression diving time Tm, which is the time until decompression is required, is calculated (step S).
6). The no-decompression diving time Tm is calculated by the following equation. Tm = −H × log (1−F) / log2 (3) Here, F is given by the following equation. F = (M10−P) / (N−P) (4) In the above formula (3), Tm is satisfied and calculation is possible only under the condition 1−F> 0. The condition is 1> F, that is, M10 <N. That is, when the nitrogen partial pressure N of the breathing gas of the diver exceeds the safe allowable limit amount, and if this condition is not satisfied, the nitrogen partial pressure in the body will reach the safe allowable limit amount forever. It cannot be exceeded.

Next, as the remaining safety activity time Ts, a value obtained by subtracting the cumulative Tr of the decompression stop time from the remaining activity time Tb is set (step S7). However, now
Assuming that the vehicle dives on the route X1 shown in (1), the accumulated Tr of the decompression stop time is “0”, and therefore the remaining activity time Tb remains as it is and the safety activity time Ts remains. next,
The present internal nitrogen partial pressure Q is set to the previous internal nitrogen partial pressure P (step S8), and display output is performed. In this display output, since no decompression diving is currently being performed, as shown in FIG. 1, the water depth, the diving time, the infinite pressure diving time, the safe activity available time, etc. are displayed and output on the display unit 3. Also, FIG.
The display "FREE" indicates that there is no need to reduce the pressure.

When the display output is performed, it is checked whether or not the diving is completed (step S10). If the diving is not completed, the process returns to step S2, the water pressure and the cylinder pressure are similarly detected, and the process is repeated.

Next, when the diver dives along the route X2 shown in FIG. 5, the internal nitrogen partial pressure Q at this time gradually increases with the passage of time to reach the safe allowable limit amount M10 or more. When the internal nitrogen partial pressure Q this time becomes equal to or higher than the safe allowable limit amount M10 in step S5, the CPU 14 calculates the decompression stop time Tg and the decompression stop depth Dg (step S1.
1), accumulation processing of decompression stop time Tg (Tr ← Tr + T
g) is performed to obtain the cumulative Tr of the decompression stop time (step S12). The decompression stop water depth Dg is a value of n such that N> Mn, and is determined by the following equation. Dg = n (5) Here, n = 10, 20, 30, ...

The decompression stop time Tg is calculated by the following equation using the depth M value calculated as the decompression stop depth. Tg = −H × log (1−F) / log2 (6) However, when F = (Mn−P) / (N−P) cumulative Tr of decompression stop time is calculated, the process proceeds to step S7, and Similarly, the remaining safe activity time Ts is calculated by subtracting the accumulated Tr of the decompression stop time from the remaining activity time Tb.

The remaining safety activity time Ts is calculated by the following equation. Ts = Tb-Tr (7) In step S7, the cumulative Tr of the decompression stop time is calculated in FIG. 5 for the case where the decompression stop is performed only once. However, depending on the diving depth, This is because it may be necessary to perform decompression stop multiple times, and in such a case, each decompression stop time is accumulated. Set this body nitrogen partial pressure Q as the last body nitrogen partial pressure P,
Display output is performed (step S9). In this display output, since the decompression stop dive is now being performed, as shown in FIG. 2, the water depth, the diving time, the decompression stop water depth, the decompression stop time, the safe activity time, etc. are displayed and output on the display unit 3. .. Further, in FIG. 2, the display "STOP" indicates that the decompression stop is required.

As described above, even in a dive requiring a decompression stop, it is possible to calculate and display the safe activity possible time in consideration of the time required for the decompression stop, and improve the safety in diving. You can

FIGS. 7 to 9 are views showing another embodiment of the electronic water depth gauge of the present invention. In this embodiment, the safe activity time is calculated in consideration of the time required for ascending. It is a thing. Further, the present embodiment is applied to an electronic water depth gauge similar to the electronic water depth gauge 1 shown in FIGS. 1 to 3 above, and is used in FIGS. 1 to 3 in the description of this embodiment. The same reference numerals are used as they are and the description thereof is omitted.

The electronic water depth gauge 1 of this embodiment has its RAM.
In FIG. 16, as shown in FIG. 7, as in the above-mentioned embodiment, the diving time T, the half-saturation time H, the safety factor K, the present internal nitrogen partial pressure Q, the previous internal nitrogen partial pressure P, and the nitrogen in the respiratory gas. Partial pressure N,
The remaining activity time Tb calculated from the cylinder pressure, the no-decompression dive time Tm, the decompression stop time Tg, the decompression stop depth Dg, the remaining safe activity time Ts, the accumulated Tr of the decompression stop time, and the like are stored, and the ascent time Ti is stored. Remember.

In the present embodiment, the process is performed as shown in FIG. 8. This process is the process shown in FIG. 6 in which the remaining safety activity time Ts is calculated in consideration of the ascent time Ti. Therefore, in the description of FIG. 8, the same process numbers as those in FIG. 6 are given the same step numbers, and the description thereof will be omitted.

In FIG. 8, when the initialization process and the water pressure and the cylinder pressure are detected, the water depth, the nitrogen partial pressure N of the breathing gas and the remaining activity time Tb are calculated, and the internal nitrogen partial pressure Q of this time is calculated ( Step S1 to step S
4). When the internal nitrogen partial pressure Q does not reach the safe allowable limit amount M10, the infinite pressure diving time Tm is calculated.
When the infinite pressure dive time Tm is calculated, the floating time Ti is calculated (step S21). The calculation of the floating time Ti is
The following formula is used. Ti = water depth / average levitation speed (8) Here, the levitation speed is set by the diver by operating the switch unit 24 or by referring to past log data. Now, since the infinite pressure diving shown in the route X1 of FIG. 9, that is, the diving that does not require the decompression stop is being performed, the levitation time is only Tib shown in FIG. 9, and the levitation time Ti is Ti = It becomes Tib.

Next, the remaining safety activity time Ts is calculated (step S22). The remaining safety activity time Ts is calculated by subtracting the cumulative Tr of the decompression stop time and the floating time Ti from the remaining activity time Tb as shown in the following equation. Ts = Tb-Tr-Ti (9) When the remaining safety activity time Ts is calculated, the current internal nitrogen partial pressure Q is set as the previous internal nitrogen partial pressure P (step S8), and the display output is performed ( In step S9), it is checked whether or not the diving is completed (step S10).

If the diving is not finished, the process returns to step S2, and similarly, the water pressure and the cylinder pressure are detected (step S2). From the water pressure and the cylinder pressure, the water depth, the nitrogen partial pressure N of the breathing gas, the remaining activity time Tb, and the present body nitrogen partial pressure Q are calculated (steps S3 and S4), and the present body nitrogen partial pressure Q is set as a safe allowable limit amount. Compare with M10 (step S
5). If the internal nitrogen partial pressure Q at this time is equal to or more than the safe allowable limit amount M10, it is determined that the decompression requires a decompression stop, and the decompression stop time Tg and the decompression stop depth Dg are calculated (step S11). Accumulation processing of the decompression stop time Tg (Tr ← Tr + Tg) is performed to obtain a cumulative Tr of the decompression stop time (step S12). When the cumulative Tr of the decompression stop time is calculated, the process proceeds to step S21 and the floating time Ti is calculated. Since it is a case where decompression stop is required now, assuming that diving is performed along the route X2 shown in FIG. 9, the ascending time Ti in this case is T as shown in FIG.
i = Tia1 + Tia2. Therefore, as the floating time Ti, it is possible to adopt a total time of the time Tia1 from the current water depth to ascend to the decompression stop water depth Dg and the time Tia2 required to ascend to the water surface from the decompression stop water depth Dg.

Next, the remaining safety activity time Ts is similarly calculated according to the above equation (8) (step S22), and the present internal nitrogen partial pressure Q is set to the previous internal nitrogen partial pressure P (step S8). , Display output is performed (step S9).

In step S10, it is checked whether or not the dive is completed. If the dive is not completed, the process returns to step S2 and the same processing is repeated. When the diving is finished in step S10, the process is finished.

As described above, according to the present embodiment, the remaining safety activity time Ts is obtained by subtracting the surfacing time Ti from the remaining activity time Tb. Therefore, the remaining safety activity time Ts is used as the actual diving activity. The time that can be performed can be obtained and displayed and output. As a result, it is possible to perform diving activities only for the remaining safety activity time Ts that is displayed and output, without the human being considering the decompression stop time and the time required for ascent, and further improve the safety during diving. Can be made In particular, even in the case where decompression diving is not required, the remaining activity time Tb
Since the remaining safety activity time Ts is calculated by subtracting i, the remaining safety activity time Ts displayed and output without human consideration of the time required for ascent even when decompression diving is not required. The dive activity can be carried out only during the time, and the safety can be improved.

[0041]

According to the present invention, when diving requires decompression diving, the diving possible time is
It is possible to calculate and output the safety activity possible time in consideration of the time required for decompression stop and the ascent time. as a result,
By diving according to the output safe diving time during diving, decompression stop and ascent can be performed within the safe diving time, and safety during diving can be improved.

[Brief description of drawings]

FIG. 1 is an external view showing a display when the electronic water depth gauge of the present invention does not require decompression.

FIG. 2 is an external view showing a display when decompression of the electronic water depth gauge of the present invention is required.

FIG. 3 is a circuit block diagram of an electronic depth gauge of the present invention.

FIG. 4 is a diagram showing a part of data stored in a RAM according to an embodiment of the present invention.

FIG. 5 is an explanatory view of the operation of the embodiment of the present invention.

FIG. 6 is a flowchart showing various operation processes of the electronic water depth gauge according to the embodiment of the present invention.

FIG. 7 is a diagram showing a part of data stored in a RAM according to another embodiment of the present invention.

FIG. 8 is a flowchart showing various operation processes of an electronic water depth gauge according to another embodiment of the present invention.

FIG. 9 is an operation explanatory view of another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic water depth meter 2 Main body case 3 Display section 4, 5, 6 switch 11 Oscillation circuit 12 Frequency dividing circuit 13 Count clock circuit circuit 14 CPU 15 ROM 16 RAM 17 Pressure sensor 18 Amplification circuit 19 A / D conversion circuit 20 Cylinder 21 Pressure sensor 22 Amplification circuit 23 A / D conversion circuit 24 Switch section 25 Display drive circuit

Claims (6)

[Claims] 1. A safe limit amount storage means for storing a safe allowable limit amount when a partial pressure of an inert gas in a tissue of a human body floats during diving, a water depth detecting means for detecting a water depth, and a residence time for each water depth. And a depressurization condition setting for setting the depressurization condition necessary for ascent from the safe allowable limit amount stored in the safety limit amount storage unit based on the detection result of the water depth detection unit and the timing result of the time measurement unit. Means, a dive possible time calculating means for calculating a dive possible time from the amount of gas used for diving, and a safe activity possible time calculated based on the calculation result of the dive possible time calculating means and the setting result of the decompression condition setting means. And a means for outputting the calculation result of the safe activity possible time calculating means in a predetermined output form. . 2. The decompression condition setting means sets a decompression stop water depth and a decompression stop time, and the safe activity possible time calculating means calculates the decompression stop time from the diving possible time calculated by the diving possible time calculating means. The electronic water depth gauge according to claim 1, wherein the safe actionable time is calculated by subtracting the time. 3. The decompression condition setting means sets a decompression stop water depth and a decompression stop time, and the safety activity possible time calculating means calculates the decompression stop time from the diving possible time calculated by the diving possible time calculating means. 2. The safe activity possible time is calculated by subtracting the levitation time required to ascend from the current water depth to the decompression stop water depth and from the decompression stop water depth to the water surface at a predetermined levitation speed. Electronic depth gauge. 4. When the decompression condition setting means sets the decompression stop water depth and the decompression stop time, and the safe activity possible time calculating means does not require decompression stop, the dive calculated by the diving possible time calculating means. The safe activity possible time is calculated by subtracting the ascent time required to ascend from the current water depth to the water surface at a predetermined ascent speed from the possible time, and when decompression stop is required, calculation by the diving possible time calculation means The safe activity possible time is obtained by subtracting the decompression stop time and the floating time required to ascend from the current water depth to the decompression stop water depth at a predetermined floating speed and from the decompression stop water depth to the water surface from the diving possible time The electronic water depth gauge according to claim 3, which is calculated. 5. The electronic depth gauge according to claim 1, wherein the inert gas in the tissue is nitrogen gas. 6. An electronic depth gauge, wherein the output means is display output means.