JPS63143035A - Automatic calibration apparatus of sensor for measuring gas partial pressure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a sensor for measuring gas partial pressure that automatically calibrates the output of a sensor for measuring transcutaneous oxygen partial pressure in two or more types of standard gas atmospheres. Relating to an automatic calibration device.

[Prior Art] It is widely practiced to measure the partial pressure of gases such as carbon dioxide gas and oxygen gas in blood using an electrochemical sensor such as a sensor for measuring transcutaneous oxygen partial pressure.

When gas partial pressure is measured using such an electrochemical sensor, the measurement is performed while calibrating the sensor in order to maintain measurement accuracy. Below, carbon dioxide gas partial pressure (hereinafter, P
This will be explained by taking as an example the measurement of CO2 (referred to as CO2). P.C.O.
Since the two sensors show a constant value for gases with the same PCO2 value, the standard gas of known PCO2, that is,
Generally, automatic calibration is performed by a two-point calibration method using air mixed gases having two types of carbon dioxide concentrations (hereinafter referred to as low gas and high gas).

[Problems to be solved by the invention] By the way, in the conventional automatic calibration device for PCO2 sensor,
In order to avoid calibration when low gas or high gas is not normally supplied, two types of calibration are performed: one using low gas (hereinafter referred to as low calibration) and one using high gas (hereinafter referred to as high calibration). The potential of the PCO2 sensor during low calibration and the PCO during high calibration
The potentials of the two sensors are compared, and if the difference between these potentials is within the range, it is determined that the calibration has been performed normally. In other cases, a method is adopted in which it is determined that the calibration has not been performed normally and the calibration is redone. For this reason, when performing automatic calibration, it is necessary to always perform low calibration and high calibration, and there is a drawback that automatic calibration takes a long time.

Therefore, the main object of the present invention is to provide means for detecting abnormality in the supply of two or more types of standard gases, and to automatically stop calibration when the standard gases are not supplied normally. By providing an automatic calibration device for a gas partial pressure measurement sensor that solves the problem of always having to calibrate two or more types of standard gases during automatic calibration and shortens the time for automatic calibration. be.

[Means for Solving the Problems] The present invention is an automatic calibration device for a gas partial pressure measurement sensor that calibrates a gas partial pressure measurement sensor in two or more types of standard gas atmospheres. A standard gas supply source that supplies gas, a sensor mounting part for mounting a gas partial pressure measurement sensor and placing the gas partial pressure measurement sensor in a standard gas atmosphere, and A detection means is provided on the circuit that leads the standard gas to the storage section and detects an abnormality in the supply of the standard gas, and a detection means is provided on the gas circuit and detects any of two or more types of standard gas supplied from the standard gas supply source. A gas switching means for selecting and supplying the gas to the sensor mounting section, a storage means for storing the output of the gas partial pressure measurement sensor, and a standard gas being introduced to the gas partial pressure measurement sensor mounted on the sensor mounting section. The output of the gas partial pressure measurement sensor is stored in the storage means when the gas partial pressure measurement sensor is in the The automatic calibration control means interrupts the storage of the output of the gas partial pressure measurement sensor in the storage means in response to detection of an abnormality in gas supply.

[Operation] The automatic calibration device for a gas partial pressure measurement sensor according to the present invention can be used when one of two or more types of standard gases is guided to the gas partial pressure measurement sensor placed on the sensor placement part. To,
The time required for automatic calibration is shortened by interrupting automatic calibration when an abnormality in the supply of standard gas is detected.

[Embodiment of the Invention] FIG. 1 is a diagram for explaining an overview of an example of the invention. In FIG. 1, the gas supply source supplies high gas and low gas, and the high gas and low gas supplied from this gas supply source are supplied to the gas switching means via the detection means. The detection means detects an abnormality in the supply of low gas and high gas. The gas switching means selectively supplies either the supplied high gas or low gas to the sensor mounting portion. The sensor mounting section is for mounting a gas partial pressure sensor, and the mounted gas partial pressure sensor is placed in an atmosphere of high gas or low gas switched by the gas switching means, and automatic calibration is performed. That is, the output of the gas partial pressure sensor is stored in the storage means by the automatic calibration control means. When an abnormality in the supply of high gas or low gas is detected by the detection means, the automatic calibration control means interrupts storage of the output of the gas partial pressure sensor in the storage means.

FIG. 2 is a schematic block diagram of an embodiment of the present invention,
FIG. 3 is a piping diagram of a gas circuit in one embodiment of the present invention, and FIG. 4 is a diagram showing the configuration of a sensor spot. .

First, the configuration of an embodiment of the present invention will be described with reference to FIGS. 2 to 4. When the Pco2 sensor 5 is placed on the sensor spot 27, it is placed in a standard gas atmosphere, and its output is given to the A/D converter 6 and converted into a digital signal. This digital signal is given to the CPU 12 via the input port 7.

The input boat 7 is connected to a low gas supply abnormality detection pressure switch 8, a high gas supply abnormality detection pressure switch 9, an automatic calibration switch 10, and an automatic calibration execution procedure changeover switch 11. One contact of these switches 8 to 11 is connected to the power supply Vcc, and the other contact is grounded.

The pressure switch 8 for detecting abnormality in low gas supply and the pressure switch 9 for detecting abnormality in high gas supply are connected to the gas circuit shown in FIG.

This shows a state in which high gas is being supplied normally. Then, when an abnormality in the supply of raw gas occurs and the pressure in the piping of the gas circuit becomes below a certain value, the pressure switch 8 for detecting abnormality in raw gas supply is switched to the contact on the power supply Vcc side. Similarly, the pressure switch 9 for detecting high gas supply abnormality can also be used when an abnormality occurs in the high gas supply.
The contact is switched to the power supply Vcc side. The automatic calibration switch 10 is used to select execution of automatic calibration, and the automatic calibration execution procedure changeover switch 11 is used to select execution of low calibration or high calibration.

The aforementioned input board 7 is connected to the CPU 12, as well as a clock generator 13, a ROM 14, and a RAM.
15 and an output port 16 are connected. ROM
A program for controlling the CPU 12 is stored in advance in 14, and the CPU 12 reads necessary data from the input port 7, exchanges data with the RAM 15, or generates a clock according to this program. The clock signal supplied from the device 13 is used to count time as an interrupt process, and necessary data is output to the output port 16. The output boat 16 includes a display section 17 and three-way solenoid valves 18 and 1.
9 is connected. Display section 17 is output port 16
A message indicating an abnormality in the supply of low gas or abnormality in the supply of high gas is displayed according to the signal given from the controller. The three-way solenoid valves 18 and 19 switch between supplying high gas or low gas based on the output of the output port 16.

Next, the configuration of the gas circuit will be explained with reference to FIG. The low gas cylinder 21 supplies low gas, and the high gas cylinder 22 supplies high gas. The low gas cylinder 21 and the high gas cylinder 22 are each connected to pressure regulators 23 and 24 via piping. These pressure regulators 23 and 24 each adjust the low gas and high gas to approximately 1.5 kg/cm.
The pressure is adjusted to 2. Pressure regulator 23°24
On the outlet side, there is a pressure switch 8 for detecting abnormality in the raw gas supply.
and a pressure switch 9 for detecting high gas supply abnormality. These low gas supply abnormality detection pressure switch 8 and high gas supply abnormality detection pressure switch 9
Flow rate regulators 25 and 26 are connected to the outlet side of the flow rate regulators 25 and 26 via piping.

These flow rate regulators 25 and 26 are for adjusting the flow rates of low gas and high gas to approximately 5 mQ/min. Further, the three-way solenoid valves 18, 19 shown in FIG. 1 mentioned above are connected to the outlet sides of these flow rate regulators 25, 26.

A sensor spot 27 is connected to the outlet side of the two-way electromagnetic valve 18 and 19.

The sensor spot 27 is used to calibrate the PCO□ sensor 5 by placing the PCO2 sensor 5 thereon. For this purpose, the sensor spot 27 is constructed as shown in FIG. That is, the low gas or high gas led from the gas circuit explained in FIG.
The sensitive surface 51 of the O2 sensor 5 is placed in a low gas atmosphere or a high gas atmosphere. The gas outlet passage 274 is provided for the purpose of keeping the pressure within the gas reservoir section 272 substantially equal to atmospheric pressure and for the purpose of rapidly exchanging gas within the gas reservoir section 272. Furthermore, the rotation arm 275 presses the PCO2 sensor 5 against the ring-shaped packing 271 due to the tension of the spring 276, thereby preventing gas from leaking between the PCO2 sensor 5 and the sensor spot 27.

FIG. 5 is a flowchart showing the main routine of an embodiment of the present invention, FIG. 6 is a diagram showing a subroutine for canceling automatic calibration, FIG. 7 is a diagram showing a standby subroutine, and FIG. 8 is a diagram showing a subroutine for waiting. The figure shows a clock signal interrupt processing routine.

Next, with reference to FIGS. 2 to 8, specific operations of an embodiment of the present invention will be described.

First, place the PCO□ sensor 5 on the sensor spot 27 shown in FIG. 4, operate the automatic calibration switch 10, and select execution of automatic calibration.The main routine program shown in FIG. Start. First, CPU1
2 clears a counter, which is a variable for measuring time, in step (abbreviated as SP in the figure) SPI. This variable is stored in the RAM 5, and is incremented in the interrupt processing routine shown in FIG. 8, which is executed by a clock signal input from the clock generator 13 to the CPU 12 at regular intervals. In step SP2, the CPU 12 activates the three-way solenoid valve 18 for raw gas.
and close the high gas three-way solenoid valve 19. Thereby, the pressure of the raw gas discharged from the raw gas cylinder 21 is adjusted by the pressure regulator 23, and the flow rate is further adjusted by the flow rate regulator 25, and the raw gas is supplied to the sensor spot 27.

In step SP3, the CPU 12 determines whether raw gas is being supplied normally. This determination is made by reading the output voltage of the low gas supply abnormality detection pressure switch 8 via the input boat 7. That is, when the output voltage of the pressure switch 8 for detecting abnormality in raw gas supply is Ov, it is determined that the raw gas supply is normal, and when the output voltage is Vcc, it is determined that the raw gas supply is abnormal. If the raw gas supply is not normal, the process proceeds to step SP4, and the process of canceling automatic calibration shown in FIG. 6 is executed. That is, the CPU 12
7 displays a message indicating that the raw gas supply is abnormal.

However, if the raw gas supply is normal, step SP
5, based on the clock output of the time counter, 14
Determine whether time has elapsed.

Then, the CPU 12 performs the steps SP2 and SF3 described above until the time measurement output of the time counter reaches 17 hours.
Repeat the action. This is an operation for waiting until the sensor spot 27 is in a low gas atmosphere and the PCO2 sensor 5 placed on the sensor spot 27 is stabilized in the low gas atmosphere. If the supply of raw gas becomes abnormal before 17 hours have elapsed, the operation of canceling automatic calibration in step SP4 is executed.

In step SP5, when the CPU 12 determines that 14 hours have elapsed from the time counter output, the CPU 12 reads the output voltage (pL) of the PCO2 sensor 5 converted by the A/D converter 6 via the input port 7. Then, it is stored in the RAM 15. The CPU 12 performs step SP7.
At this point, it is determined whether the execution procedure has been changed by the automatic calibration execution procedure changeover switch 11. Here, if the execution procedure has not been changed by the automatic calibration execution procedure changeover switch 11, the process advances to step SP8, and the standby routine shown in FIG. 7 is executed.

That is, the CPU 12 closes the three-way solenoid valve 18 in step SP81 to stop the gas supply, and then proceeds to step SP81.
At P82, the time counter is cleared. Then, in step 5P83, it is determined whether or not the automatic calibration switch 10 is turned on. If it is not turned on, automatic calibration is ended in step 5P84. If the automatic calibration switch 10 is turned on, step 5P8
In step 5, it is determined whether or not the clock output of the time counter has exceeded 18 hours. If 13 hours have not passed,
Repeat steps SpH13 and 5P85, and
When it is determined that one hour has elapsed, the process returns to the main routine shown in FIG. 5 again.

If the execution procedure has been changed by the automatic calibration execution procedure changeover switch 11 in step SP7 described above, the time counter is cleared in step SP9. Then, in step 5PIO, the CPU 12 closes the three-way solenoid valve 18 for low gas, and opens the three-way solenoid valve 19 for high gas to supply high gas to the sensor spot 27. That is, the pressure of the high gas discharged from the high gas cylinder 22 is adjusted by the pressure regulator 24, and the flow rate thereof is adjusted by the flow rate regulator 26. The high gas is then supplied to the sensor spot 27 via the three-way solenoid valve 19. CPU12 is step 5P
In II, it is determined whether or not high gas is being supplied normally.

If the high gas supply is not normal, the automatic calibration is stopped in step 5P12, and a message indicating that the high gas supply is abnormal is displayed on the display unit 17. If high gas is being supplied normally, step 5P13
At this point, it is determined whether or not the clock output of the time counter has exceeded 12 hours. If 12 hours have not passed,
The operations of steps 5PIO and 5P11 are repeatedly executed, and if 12 hours have elapsed, in step 5P14, the output of the PCO2 sensor 5 (PM ) and store it in RAM8. Thereafter, the CPU 12 executes the standby processing routine shown in FIG.

Here, the operating method when an abnormality in the supply of low gas or high gas occurs will be explained. First, when an abnormality in the supply of low gas or high gas is detected, a message indicating that the gas supply is abnormal is displayed on the display unit 17. After checking the message, the user selects the end of automatic calibration using the automatic calibration switch 10. . If you choose to end automatic calibration,
The automatic calibration program ends. The user then takes measures to restore the gas supply to normal, such as replacing the low gas cylinder 21 or the high gas cylinder 22, and again selects execution of automatic calibration using the automatic calibration switch 10, as shown in FIG. Restart the automatic calibration program.

Figures 9A and 9B are diagrams showing the connection between the PCO□ sensor and this device in other embodiments of the present invention. In particular, Figure 9A shows a state in which the PCO2 sensor is not connected, and Figure 9B shows a state in which the PCO2 sensor is not connected. The figure shows a state in which the PCO2 sensor is connected.

In FIGS. 9A and 9B, the connector 31 is
It is provided on the O2 sensor side, and terminals 32 and 33 are short-circuited. The connector 34 is provided on the device side,
The terminal 35 is connected to the input boat 7, and
It is connected to a DC power supply Vcc via a pull-up resistor 37, and a terminal 36 is grounded. Therefore, the second
When the PCO2 sensor 5 shown in the figure is not connected to the device side, the voltage of the power supply Vcc is applied to the input boat 4. However, when the PCO2 sensor 5 is connected to the device, the terminals 32 and 33 of the connector 31 on the PCO2 sensor 5 side are connected to the terminals 35 and 33 of the connector 34 on the device side.
Since input boat 4 is connected to
A voltage of v is given.

FIG. 10 is a diagram showing a clock signal interrupt processing routine according to another embodiment of the invention, and FIG. 11 is a diagram showing the main routine as well.

Next, specific operations of other embodiments of the present invention will be described. When the CPU 12 receives a clock signal from the clock pulse generator 13, it proceeds to the clock signal interrupt processing routine shown in FIG. Then, in step 5P21, the time counter is incremented by 1, and in step SP22, it is determined whether the pco and sensor 5 are connected. This determination can be made by reading the voltage input to the input port 7 from the connector 34.

That is, the CPU 12 determines that the PCO2 sensor 5 is not connected when the voltage input to the input boat 7 is the power supply Vcc, and determines that the PCO2 sensor 5 is connected when it is Ov.

If PCO□ sensor 5 is not connected,
In step SP23, the sensor flag stored in the RAM 15 is set to "0" and the execution of the clock signal interrupt processing routine is ended. However, if it is determined that the PCO2 sensor 5 is connected, the CPU 12 performs step 5.
At P24, it is determined whether the sensor flag is 0 or not, and if the sensor flag is 0, the value of the sensor flag is set to 2.
As a result, execution of the clock signal interrupt processing routine ends. This sensor flag is a variable that indicates the connection state of the PCO□ sensor 5, and the flag θ'' indicates the state in which the PCO2 sensor 5 is not connected, and the flags 1'' and ``2'' indicate that the PCO□ sensor 5 is connected. It represents the state of being. Flag 2# represents a state in which the state in which the PCO2 sensor 5 is not connected has changed to the state in which the PCO2 sensor 5 is connected and automatic calibration has not been executed. Further, flag 1'' represents other states.

Next, the main routine shown in FIG. 11 will be explained. In FIG. 11, steps SPI to SF3 are the same as those in FIG. 5 described above, and their explanation will be omitted. CPU12
In step 5P16, it is determined whether the sensor flag is "2" or not. If the sensor flag is not "2#", the process advances to step S8 and a standby subroutine is executed.

However, if the sensor flag is “22”, step 5P
After setting the sensor flag to "1" in step SP17, steps SP9 to SP5 are performed in the same manner as described in FIG.
Execute the operation of P15. That is, in another embodiment of the present invention, the CPU notifies that the PCO2 sensor 5 has been replaced.
12, the automatic calibration execution procedure is automatically switched.

As described above, according to this embodiment, the PCO2 sensor 5
Only when you need to perform low and high calibrations, such as when replacing the This makes it possible to shorten the execution time of automatic calibration.

In the above-mentioned embodiment, the present invention is applied to an automatic calibration device for the PCO2 sensor 5, but the present invention is not limited to this, and can be applied to a transcutaneous oxygen partial pressure sensor, a transcutaneous oxygen partial pressure sensor, or a transcutaneous carbon dioxide gas partial pressure sensor. Needless to say, it is applicable.

[Effects of the Invention] As described above, according to the present invention, an abnormality in the supply of the standard gas is detected when one of two or more types of standard gases is being guided to the gas partial pressure measurement sensor. In response to the,
Since automatic calibration is now interrupted, the conventional problem of not being able to detect standard gas supply abnormalities has been solved unless automatic calibration is performed using the two-point calibration method using two types of standard gases. This can reduce the execution time of automatic calibration.

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining the invention in detail. FIG. 2 is a schematic block diagram of an embodiment of the present invention. FIG. 3 is a diagram showing a gas piping route for standard gas. FIG. 4 is a diagram showing the configuration of the sensor spot. FIG. 5 is a flow diagram showing the main routine of one embodiment of the present invention. FIG. 6 is a flow diagram showing a subroutine for canceling automatic calibration. FIG. 7 is a flow diagram showing the standby subroutine. FIG. 8 is a flow diagram showing the clock signal interrupt processing routine. FIGS. 9A and 9B are diagrams showing a connection part of a PCO2 sensor in another embodiment of the present invention. FIG. 10 is a flow diagram showing a clock signal interrupt processing routine according to another embodiment of the present invention. FIG. 11 is a diagram showing the main routine of another embodiment of the invention. In the figure, 5 is a PCO2 sensor, 6 is an A/D converter,
7 is an input boat, 8 is a pressure switch for detecting low gas supply abnormality, 9 is a pressure switch for detecting high gas supply abnormality, 10 is an automatic calibration switch, 11 is an automatic calibration execution procedure changeover switch, 12 is a CPU, 13 is a clock generator, 1
4 is ROM, 15 is RAM, 16 is output port, 17 is display, 18.19 is three-way solenoid valve, 21 is low gas cylinder, 22 is high gas cylinder, 23.24 is pressure regulator, 25.26 is flow rate adjustment 27 is a sensor spot, and 31.34 is a connector. Figure 1 Figure 3? 1. Ouka “Suzanhe” zz:Mu4FXO;〉be゛275! I'm in trouble -4 zyt λ7+Resistance Fig. 5 Fig. 6 Fig. 3 Fig. 7 Fig. 10 Fig. 11

Claims (4)

[Claims] (1) An automatic calibration device for a gas partial pressure measurement sensor that calibrates a gas partial pressure measurement sensor in an atmosphere of two or more types of standard gases, the standard gas supply source supplying the two or more types of standard gases; a sensor mounting section for placing a gas partial pressure measurement sensor to be calibrated thereon and placing the gas partial pressure measurement sensor in the standard gas atmosphere; a sensor mounting section for connecting the standard gas supply source to the sensor mounting section; a detection means provided on a gas circuit that guides a standard gas to detect an abnormality in the supply of the standard gas; a detection means provided on the gas circuit and supplied from the standard gas supply source of two or more types of standard gas; gas switching means for selecting and supplying the gas to the sensor mounting section; storage means for storing the output of the gas partial pressure measurement sensor; and gas partial pressure measurement sensor mounted on the sensor mounting section is configured to supply a standard gas to the sensor mounting section; When placed in an atmosphere, the output of the gas partial pressure measuring sensor is stored in the storage means, and in response to an abnormality in the supply of the standard gas being detected by the detection means, the output is stored in the storage means. An automatic calibration device for a gas partial pressure measurement sensor, comprising automatic calibration control means for interrupting storage of the output of the gas partial pressure measurement sensor. (2) The automatic calibration control means includes a selection means for selecting an execution procedure for automatic calibration, and a switch between the two or more standard gases by the gas switching means according to the selection of the execution procedure by the selection means; 2. The automatic calibration device for a gas partial pressure measurement sensor according to claim 1, further comprising: automatic calibration execution means for executing automatic calibration in accordance with the switched standard gas. (3) The selection means includes a removal detection means for detecting that the gas partial pressure measurement sensor is removed from the apparatus, and a removal detection means for detecting that the gas partial pressure measurement sensor is removed by the removal detection. and a determination means for determining that the gas partial pressure measurement sensor has been removed, and the automatic calibration control means changes the automatic calibration execution procedure in response to the determination by the determination means that the gas partial pressure measurement sensor has been removed. including means;
An automatic calibration device for a sensor for gas partial pressure measurement according to claim 1 or 2. (4) The gas partial pressure measurement sensor includes a transcutaneous oxygen partial pressure measurement sensor, a transcutaneous carbon dioxide partial pressure measurement sensor, a transcutaneous oxygen partial pressure measurement sensor/a transcutaneous carbon dioxide partial pressure measurement sensor. An automatic calibration device for a gas partial pressure measurement sensor according to any one of claims 1 to 3.