JP4532918B2 - Digital self-recording pressure gauge for governor room - Google Patents

Description

  The present invention relates to an improvement in a digital self-recording pressure gauge used in a gas supply governor chamber.

  In the gas supply business, governors are installed at the bases of the high and medium pressure conduits, which are the main lines for gas supply, to maintain the gas pressure at a constant level, and the governor room has pressure on the primary and secondary sides of the governor. A self-recording pressure gauge is recorded.

(First prior art)
As this type of self-recording pressure gauge, a digital self-recording pressure gauge proposed by the applicant of the present application is known (see Patent Document 1).

  FIG. 1 shows a state in which this digital self-recording pressure gauge is connected to a gas conduit in a governor chamber. In FIG. 1, a primary side gas conduit 1 that is a high pressure side and a secondary side gas conduit 2 that is a low pressure side are connected via a governor 3, and supply pressure in the secondary side gas conduit 2 by the governor 3. Is held constant.

  A pressure extraction pipe 4 is connected to the gas conduit 1 on the primary side, and a connector 5 is provided at the tip thereof. Further, a pressure take-out pipe 6 is connected to the secondary side gas conduit 2, and a connector 7 is provided at the tip thereof. The primary side connector 5 is connected to a connector 9 provided in a primary side pressure sensor 8 which is an inlet side pressure sensor, and the secondary side connector 7 is connected to a secondary side pressure sensor 10 which is an outlet side pressure sensor. The connector 11 provided in the is connected.

  Both the pressure sensors 8 and 10 sense the gas pressure in the gas conduits 1 and 2 connected to each other, and transmit a voltage changing due to the pressure change to the acquisition device 14 side as an electrical signal through the cables 12 and 13. It has become. Further, a primary side connector 15 is attached to the other end of the primary side cable 12, and this is detachably connected to a primary side connector 16 provided in the acquisition device 14. Further, a secondary side connector 17 is attached to the other end portion of the secondary side cable 13, and this is detachably connected to a secondary side connector portion 18 provided in the acquisition device 14.

  A battery box 19 is detachably attached to the acquisition device 14, and a cable 20 is connected to the battery box 19, and a connector 21 attached to the other end of the cable 20 is provided in the acquisition device 14. The connector portion 22 is detachably connected.

  The case 14a of the acquisition device 14 is formed with an insertion hole 24 that forms a mounting portion for a PC card 23 that is a recording medium, with its lower end opened, and an opening / closing lid provided at the lower end of the opening is shown in the lower part of the figure. The PC card 23 can be detachably inserted into the insertion hole 24 from the lower surface of the case 14a.

  Next, the recording device 14 and the battery box 19 will be described with reference to FIG. The acquisition device 14 inputs the voltage generated in both the pressure sensors 8 and 10 through both the connector portions 16 and 18, performs A / D conversion by the A / D converter 26, and stores it in the memory of the CPU 27. A liquid crystal display 28 for displaying necessary data among the data stored in the CPU 27, a display switch 29 for displaying and operating the liquid crystal display 28, and a PC card 23 to which the data stored in the CPU 27 is attached. A PC card interface 30 for recording, a communication interface 31, and a communication connector 31a are provided.

  When the display switch 29 is turned on, the screen of the liquid crystal display 28 displays the maximum pressure and the minimum pressure in the recording period of the primary side pressure and the secondary side pressure, the generation date and time, the current pressure and the current time, respectively. It can be displayed.

  The battery box 19 contains a dry battery 32 and a current limiting resistor 33 connected in series with the battery box 19, and the dry battery 32 drives the recording device 14 and the pressure sensors 8 and 10 through the cable 20. The current limiting resistor 33 is a so-called intrinsically safe explosion-proof circuit in which even if some accident (short circuit etc.) occurs on the side of the acquisition device 14, the current is limited and the ignition energy to the gas is suppressed to prevent ignition. (The cheap circuit). Further, since the battery box 19 and the acquisition device 14 are separable and the cable 20 is separable from the acquisition device 14 by the connectors 21 and 22, the battery box 19 is separated from the gas conduit portion of the governor chamber. You can take it out and replace the battery.

  A mounting piece (not shown) is provided on the case 14a of the acquisition device 14, and the acquisition device 14 and the battery box 19 are attached to the wall surface of the governor chamber by the attachment piece.

  Both pressure sensors 8, 10 are time-division driven by a program of the CPU 27 in the acquisition device 14. The driving cycle (measurement cycle) is, for example, every 0.5 seconds. The drive time is about 15 ms.

  By driving both the pressure sensors 8 and 10, the gas pressure in the primary side gas conduit 1 which is the high pressure side and the gas pressure in the secondary side gas conduit 2 which is the low pressure side are detected. The voltage generated in the pressure sensors 8 and 10 is A / D converted by the A / D converter 26 and stored in the memory of the CPU 27. In addition, the recording cycle is set to 3 minutes, and the maximum pressure value and the minimum pressure value on the high pressure side and the maximum pressure value and the minimum pressure value on the low pressure side every 3 minutes are stored, and further, the maximum pressure value and the minimum pressure value are stored. Stores the date and time of occurrence of a value.

  The stored data is written and recorded on the PC card 23 mounted in the acquisition device 14. This recording is performed every 12 minutes. That is, when data every 3 minutes is taken 4 times, it is written in the PC card 23. With such writing, for example, when a 4 MB PC card is used, the amount of data that can be recorded is about six months.

  The patrol inspector extracts and collects the PC card 23 on which the above data is recorded every predetermined period from the acquisition device 14, reads the data recorded on the PC card 23 into a personal computer, and creates a file on the personal computer side. Change and process the data. In other words, from this read data, you can check the presence or absence of pressure abnormality on the graph display screen, register the data in a hard disk or an external MO disk, etc., read the data registered in the past, etc. Perform data processing and data management.

  In this way, by processing data on a personal computer, data verification, search, etc. can be speeded up, the details of data in a desired period of 1 hour, 1 day, 1 week, etc. are easy to see, and the response to abnormal data is quick. it can. In addition, the operating time on the acquisition device side is shortened and the current consumption is also reduced. In combination with the intermittent driving of the pressure sensor, the life of the dry battery is prolonged and it is assumed that it will last for 6 months or more with 4 single batteries.

  The liquid crystal display unit 28 is normally turned off, but is turned on when the inspection inspector switches the display switch 29 of the acquisition device 14 at the site, and the maximum pressure and the minimum pressure within the recording period and the respective occurrence date and time are displayed. The current pressure and current time are confirmed.

(Second prior art)
The applicant of the present application has also proposed a remote monitoring system that transmits gas pressure data collected in a digital self-recording pressure gauge acquisition device provided in the governor room to a remote center device via a wireless transmission path (hereinafter referred to as this). Is referred to as the second prior art). (See Patent Document 2).

  This second prior art will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part same as the said 1st prior art, and the description is abbreviate | omitted as much as possible.

  Reference numeral 14A denotes a digital self-recording pressure gauge including the acquisition device 14, the battery box 19, both pressure sensors 8, 10 and the like as in the first prior art, and the collected gas pressure data is transmitted to the wireless communication unit described later as a communication line 40A. It has a communication function to send via. This digital self-recording pressure gauge includes a battery for power supply and a current limiting resistor connected in series with the battery in a battery box 19, and supplies power to the acquisition device 14 through a cable 20. The digital self-recording pressure gauge 14A is thus constituted by a battery-powered safety circuit.

  42A is a wireless communication unit using PHS, and a battery for power supply and a current limiting resistor connected in series to the battery are built in the battery box 42a, and power is supplied to the electronic circuit of the wireless communication unit through the cable 42b. Reference numeral 40A denotes a communication line for transmitting gas pressure data from the digital self-recording pressure gauge 14A to the wireless communication unit 42A. Reference numeral 55 denotes a gas alarm unit including a gas sensor 55a. The battery power source provided in the battery box 55b operates the gas sensor 55a and the attached electronic circuit every minute for one hour to intermittently perform a gas leak detection operation. Reference numeral 55c denotes a power supply cable. Thus, the radio communication unit 42A and the gas alarm unit 55 are both battery-driven and configured by a safety circuit.

  The digital self-recording pressure gauge 14A, the wireless communication unit 42A, and the gas alarm unit 55 remove the battery boxes 19, 42a and 55b together with the cables 20, 42b and 55c, respectively, at the time of battery replacement and put them in a non-hazardous area outside the governor room. Carry it out and replace the battery to make it explosion proof.

  In the system of FIG. 3, the inlet pressure of the governor 3 is converted into an electrical signal by the primary side pressure sensor 8, the outlet pressure is converted into an electrical signal by the secondary side pressure sensor 10, and the gas pressure data is acquired at regular intervals. Acquired on the device 14. The collected data is transmitted to the wireless communication unit 42A via the communication line 40A. The wireless communication unit 42A collects the sent gas pressure data for a certain period, for example, one week, and wirelessly transmits it to the base station 48 via PHS communication when the gas pressure data for a predetermined period is collected. Further, the data is transmitted to the center device 47 via the general telephone line 46. The center device 47 captures this gas pressure data into the personal computer 51 via the terminal adapter 52A. 53 is a magneto-optical disk driver.

  When the gas alarm unit 55 detects a gas leak, the gas alarm unit 55 transmits an external output signal to the wireless communication unit 42A via the signal line 56. When the wireless communication unit receives an external output signal from the gas alarm unit 55, the wireless communication unit notifies the center device 47 as an alarm signal.

  In this system, the digital self-recording pressure gauge 14A is composed of a battery-powered safety circuit, and the gas pressure data is automatically transmitted to the central unit over a certain period of time by wireless communication and a general telephone line, and also a PC card Also record the pressure data. The wireless communication unit 42A and the gas alarm unit 55 are both battery-driven and configured by a safety circuit.

  By the way, in the system of FIG. 3, the battery of the battery box 19 uses four single type alkaline batteries in series connection, and the rated voltage is 1.5V × 4 = 6.0V. Since the pressure sensors 8 and 10 and the A / D converter are 5V systems, the voltage supplied to the acquisition device 14 through a current limiting resistor connected in series to a battery having a rated voltage of 6.0V is a 5V system pressure sensor. When the 8, 10 or A / D converter is operated, the final voltage per battery becomes 5/4 = 1.25V even if the voltage drop due to the current control resistor is zero. In this state, a battery life of more than half a year cannot be realized. Therefore, the voltage supplied from the battery box is boosted by a booster circuit built in the acquisition device 14 and used for a 5V pressure sensor or an A / D converter.

  The booster circuit used in the past is of a switching type, and the boost ratio is determined by adding a voltage dividing resistor outside the dedicated booster IC. In order to use such a booster circuit safely in the governor room, which is an explosion-proof hazardous area, it is necessary to pass the explosion-proof certification regarding the intrinsically safe explosion-proof circuit of the Industrial Safety Technology Association. This explosion-proof certification requires that there is no fear of igniting the gas atmosphere even with a large voltage generated at the time of failure. In a booster circuit of a system in which a boosting ratio is determined by an external voltage dividing resistor in a boosting switching IC, when one of the resistors is short-circuited, the voltage dividing ratio may be ∞. Then, the output voltage of the booster circuit rises extremely, and there is a risk of ignition in the acquisition device 14. Therefore, in order to obtain certification as a safety circuit, a Zener diode (constant voltage diode) is connected to the output side of the booster circuit so that the output voltage is kept below a certain level.

  Such a conventional circuit around the booster circuit is shown in FIG. The battery voltage supplied from the dry battery 32 rated 6V (= 1.5 × 4) in the battery box 19 to the booster circuit 61 of the acquisition device 14 via the current limiting resistor 33 is determined by the voltage dividing resistors R1 and R2. The voltage is boosted at the step-up ratio and supplied to the pressure sensors 8 and 10 (not shown) as the output voltage Vout. ZD1 and ZD2 are Zener diodes (constant constants) connected to the output Vout so that an abnormal high voltage that may cause ignition is not applied to the pressure sensor or the like of the acquisition device 14 even if an accident occurs in the booster circuit 61. For safety, two diodes ZD1 and ZD2 are connected in parallel as is normally used in the safety circuit.

The output voltage Vout is determined to be an appropriate voltage of 5 V or more in order to operate a 5 V pressure sensor. Further, since the Zener diodes ZD1 and ZD2 have a large leakage current in the vicinity of the Zener voltage, if the Zener voltage ZD of the Zener diodes ZD1 and ZD2 is set to a value close to the output voltage Vout, the current consumption of the battery 32 is affected by the leakage current. May increase and the battery life may be shortened. In particular, diodes approved for use by the Industrial Safety Technology Association have a large leakage current. Therefore, in order to reduce the adverse effect on the battery life due to such leakage current, the Zener voltage of the Zener diodes ZD1 and ZD2 is set to a voltage 1V higher than the output voltage Vout. Furthermore, it is necessary to consider the tolerance of the Zener voltage ZD of the Zener diodes ZD1, ZD2. In addition, the limiting voltage including the temperature characteristic of the Zener voltage of the Zener diode is defined as the maximum voltage of the booster circuit for explosion protection. When the rated value of the Zener voltage of the Zener diode is ZD and the tolerance including the temperature characteristic is ± α, the minimum value ZD−α of the Zener voltage needs to be set larger than the output voltage Vout. In addition, including the consideration of 1V for leakage current,
VD-α> Zout + 1V
It is necessary to satisfy. Therefore, the maximum voltage ZD + α (V) of the Zener diodes ZD1, ZD2 is
ZD + α (V) = Vout + 1V + 2α
It becomes. Therefore, in the safety maintenance of the booster circuit 61, the maximum explosion-proof voltage is Vout + 1V + 2α, and 1V + 2α≈about 2V is higher than the output voltage Vout. The maximum explosion-proof voltage is a voltage that does not increase physically even if a circuit board, circuit, or component breaks down. Lowering the maximum voltage as much as possible improves spark ignition characteristics (safety) Leads to.

In the digital self-recording pressure gauge, a large number of digital ICs that operate by being supplied with the output voltage Vout of the booster circuit 61 are used in the acquisition device 14, and these digital ICs are mounted on a printed wiring board. A circuit board on which a large number of digital ICs are mounted includes several bypass capacitors (pass capacitors) between the ground and the power supply wiring in order to lower the apparent power supply impedance. In this safety circuit, it is necessary to design the energy when the capacitor is charged at the explosion-proof maximum voltage to a certain value or less without risk of spark ignition. Lowering leads to improvement (safety) of spark ignition characteristics.
JP-A-11-108788 JP-A-11-232579

  In the prior art as described with reference to FIG. 4, it is necessary to use double Zener diodes as safety holding parts, and thus there is a problem that the power supply circuit becomes complicated and the cost increases. In addition, the maximum voltage of the booster circuit for explosion protection is 1V + α higher than the output voltage Vout required for a 5V pressure sensor, which is a negative factor in the spark ignition characteristics of explosion protection. there were. Furthermore, since the maximum voltage of the booster circuit for explosion prevention becomes a voltage higher by 1V + 2α, there is a problem that the total capacity of the capacitor such as a bypass capacitor is limited.

  Therefore, an object of the present invention is to provide a digital self-recording pressure gauge for a governor room that can solve these problems.

  The present invention is a digital self-recording pressure gauge for a governor room, which is driven by a battery and is constituted by a safety circuit, wherein a voltage supplied from a battery via a current limiting resistor is used as a charge pump using two capacitors. The most important feature is that the voltage is boosted by the double booster circuit of the formula, and the pressure sensor or the like is supplied with the boosted voltage.

  In order to achieve the above object, the invention of claim 1 is a digital self-recording pressure gauge used in a gas supply governor chamber, wherein the pressure sensor senses the pressure on the primary side of the governor, and the pressure on the secondary side. A pressure sensor that senses the pressure, an A / D converter that converts the signal of each pressure sensor into a digital signal, and a recording device that records the pressure data converted into a digital signal,

  A charge pump type double booster circuit is provided for receiving a voltage from a battery and a battery box having a current limiting resistor connected in series with the battery, and boosting the voltage by a factor of two, and an A / D converter from the output voltage And a digital self-recording pressure gauge for the governor chamber, characterized in that the operation power is supplied to the pressure sensor.

According to a second aspect of the present invention, in the digital self-recording pressure gauge for the governor chamber according to the first aspect, the charge pump type double booster circuit includes two capacitors C1, C2, two diodes D1, D2, a switching IC, Tona is, double the output voltage of the booster circuit is supplied to the a / D converter and a pressure sensor via a constant voltage circuit, CPU of the acquisition device via another constant voltage circuit voltage from the battery box It is characterized by supplying to.

  Since the digital self-recording pressure gauge for the governor chamber according to the present invention is configured as described above, the output voltage of the booster circuit is the voltage supplied from the battery box even when the double booster circuit, particularly the switching IC, fails. Therefore, there is an advantage that two Zener diodes for voltage limitation required in the prior art are not required. Further, since the maximum voltage on explosion-proof is limited to the output voltage Vout of the booster circuit and there is no additional 2V of Vout + about 2V as in the prior art, the spark ignition characteristic as the actual safety circuit is improved. Also, since it is not necessary to use Zener diodes ZD1 and ZD2 as safety holding parts, not only is the structure simple and cost-effective, but there is a need to worry about battery consumption due to Zener diode leakage current. Also disappear. Furthermore, since the maximum voltage for explosion protection can be reduced, the spark ignition characteristics due to the charge charged to decaps etc. will also be on the safe side, and it is possible to increase the capacity of capacitors such as decaps and reduce the apparent power supply impedance. It becomes.

  Since the input voltage Vin from the battery box is boosted twice, the energy of the battery can be used effectively and the battery life is extended.

According to the second aspect of the present invention, the power supply voltage applied to the A / D converter and the pressure sensor is kept constant until a certain drop even when the voltage of the double booster circuit is lowered according to the drop of the battery power supply. The operation of the digital self-recording pressure gauge is stabilized and the accuracy of pressure measurement is improved.

Moreover, even if the operating voltage is different from that of the A / D converter and pressure sensor using a 3V system IC for the CPU, an effective and stable voltage can be supplied to the CPU. The operation of the meter is stabilized.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described based on the embodiments shown in the drawings.

  FIG. 5 is a block diagram of the first embodiment of the present invention, and the switching IC 63 used in the double booster circuit 62 equivalently shows its internal circuit with a broken line. This switching IC uses ICL7660 manufactured by MAXIM, and FIG. 6 shows a functional block diagram published by the manufacturer. Of the eight pins of the IC, only four pins 2, 2, 5, and 8 are used. An internal circuit equivalently shown based on the functional block diagram of FIG. 6 is indicated by a broken line of the switching IC 63 of FIG.

  The inside of the switching IC 63 (ICL 7660) has no capacity and is only switching.

1. When CAP + is switched to GND, the + side (point A) voltage of the capacitor C1 is (Vin−Vd). The negative side (point B) voltage of the capacitor C1 is GND. Vin
Is an input voltage from the battery box 19, and Vd is a forward voltage of the diodes D1 and D2.

  2. When CAP + is switched to V +, the voltage on the negative side (point B) of the capacitor C1 becomes Vin, and the voltage on the positive side (point A) of the capacitor C1 rises by the voltage of Vin and becomes Vin + (Vin−Vd). Become.

3. The above 1.2 is switched at 10 kHz.
FIG. 7 is a timing diagram showing voltage waveforms at points A and B. The peak value at point A is (2Vin−Vd), this voltage is smoothed by the second diode D2 and the second capacitor C2, and the output voltage Vout is approximately twice the input voltage Vin. Vout = 2Vin−2Vd
As obtained.

Even in the worst case where the switching IC 63 fails, the output voltage Vout of the booster circuit 62
Becomes 2Vin-2Vd. Further, the worst values at the time of failure at the points A and B are 2Vin−Vd and Vin. In the circuit configuration of the double booster circuit, the capacitor C1 connected to CAP + is charged to the maximum voltage (Vin−Vd) when CAP + is switched to GND inside the IC. Thereafter, when CAP + is switched from GND to V +, the voltage at point A becomes Vin + (Vin−Vd). Therefore, when the switch between CAP + and V + fails in the ON state, the maximum (2Vin−Vd) voltage can be generated at point A.

  The output voltage Vout is controlled to about 5V by a constant voltage circuit 64 using a constant voltage IC and supplied to the 5V A / D converter 26 and the pressure sensors 8 and 10. The bypass capacitors Cp are mounted at various places on the printed wiring board to lower the apparent power supply impedance and ensure the operation of the digital IC. The input voltage Vin is controlled to about 3V by another constant voltage circuit 65 using a constant voltage IC and supplies operating power to the 3V CPU 27 and the liquid crystal display drive circuit 66. The battery 32 can be used up to a final voltage of about 3.5V.

6-8 5V / 3V interface inserted between the CPU27 the 3V system and A / D converter 26 of the 5V system, 6 9 was inserted between the PC card interface 30 of CPU27 and 5V system the 3V 3V / 5V interface. Note that about 5 V of the output voltage of the constant voltage circuit 64 is also supplied to the PC card interface 30. When the voltage drops below a predetermined value, the voltage drop detection circuit 67 displays the information on the liquid crystal via the CPU or notifies the management center.

  Although the cable 20, the connector 21, and the connector 22 that electrically connect the battery box 19 and the acquisition device 14 are shown in FIG. Since the line 20 to be connected and the line 20 to which the right end of the current limiting resistor 33 is connected are shown in the figure, only the two lines are apparently connected. Actually, the description has been made with reference to FIGS. One by one.

  In addition, the same code | symbol as the prior art of FIGS. 1-4 is attached | subjected to the element which carries out the same effect | action as demonstrated with the prior art of FIGS. 1-4, and the description is abbreviate | omitted.

The figure which shows the installation state of a prior art. The block diagram which shows the wiring state of the acquisition apparatus of the prior art of FIG. 1, and a battery box part. Schematic of prior art. The electric circuit diagram around the booster circuit of a prior art. It is a block diagram of the Example of this circuit, and an electric circuit diagram is a part. 6 is a functional block diagram of a switching IC used in the embodiment of FIG. FIG. 6 is a timing diagram for explaining the operation of the switching IC used in the embodiment of FIG. 5, and is a voltage waveform diagram at points A and B;

Explanation of symbols

3 Governor 8 Primary pressure sensor 10 Secondary pressure sensor 19 Battery box 27 CPU
32 battery 33 current limiting resistor 62 double booster circuit 63 switching IC
64 constant voltage circuit 65 another constant voltage circuit

Claims (2)

This is a digital self-recording pressure gauge used in the gas supply governor chamber, which senses the pressure on the primary side of the governor, the pressure sensor that senses the pressure on the secondary side, and converts each pressure sensor signal into a digital signal. And an A / D converter that has a recording device that records pressure data converted into a digital signal,
A charge pump type double booster circuit is provided for receiving a voltage from a battery and a battery box having a current limiting resistor connected in series with the battery, and boosting the voltage by a factor of two, and an A / D converter from the output voltage And a digital self-recording pressure gauge for the governor chamber, characterized in that the operation power is supplied to the pressure sensor. Double boosting circuit of charge pump type is the two capacitors C1, C2, two diodes D1, D2, Ri Do and a switching IC, and output voltage of the double boosting circuit through a constant voltage circuit A / D 2. The digital self-recording pressure gauge for a governor room according to claim 1, wherein the voltage is supplied to the converter and the pressure sensor, and the voltage from the battery box is supplied to the CPU of the acquisition device via another constant voltage circuit. .

Images