JP2005140661A - Measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring instrument which prevents necessary data, a maximum value and a minimum value for example, from disappearing, even if momentary service interruption or the like occurs. <P>SOLUTION: If power interruption is detected, the necessary data, the maximum value and the minimum value for example, are written for protection in a nonvolatile storage or the like which does not require power for storage and retaining. Moreover, before writing the maximum value and the minimum value, the maximum value and the minimum value are compared with a maximum value and a minimum value having been written in the storage medium, necessity for the writing is judged, and by preventing unnecessary writing, the life of the storage medium such as a nonvolatile storage is extended. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a measuring instrument that measures various inputs such as temperature, voltage, and current.

A digital panel meter is known as this type of measuring device (see, for example, Patent Document 1).
JP 2002-116063 A

  This digital panel meter updates and stores the maximum and minimum values in the measurement period from when the power is turned on to the start of measurement until the present, and displays the maximum or minimum value according to the user's operation. There are things that can be confirmed.

  However, in the conventional digital panel meter, the measured maximum value and minimum value are stored in the volatile RAM. Therefore, if a momentary power failure or power failure occurs due to some factor, There is a difficulty that data of the maximum value and the minimum value is lost.

  Therefore, a user who wants to hold the required data such as the maximum and minimum values without being affected by a momentary power outage or the like outputs and holds the maximum or minimum data on another external device. There was a need.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a measuring instrument that can retain necessary data without losing data even if an instantaneous power failure or the like occurs.

  In order to achieve the above object, the present invention is configured as follows.

  That is, the present invention is a measuring instrument that measures input, and includes a power interruption detection circuit that detects that power supply has been cut off, a storage medium that does not require power for data storage, and the power interruption detection. A protection circuit that writes the required data to the storage medium and protects the required data in response to the detection output of the circuit, the protection circuit before the writing of the required data to the storage medium The required data is compared with the required data already written in the storage medium to determine whether or not writing to the storage medium is necessary.

  Here, the required data is data that should be protected from loss due to power interruption such as a momentary power failure or a power failure. For example, various parameters that define the operating state of the measuring instrument or measurement data that should be protected It is data.

  A storage medium that does not require power to store and store data is a non-volatile memory or a memory card.

  Further, determining whether or not to write is to determine whether or not required data needs to be written to the storage medium. For example, the required data is a parameter and the parameter to be written to the storage medium is determined. And the already written parameters are the same, it is determined that writing is not necessary, or the required data is the maximum value and the maximum value to be written to the storage medium is less than the maximum value already written. In some cases, the necessity of writing is determined such that writing is not required, and meaningless writing is not performed.

  Moreover, the measuring device should just be an apparatus which measures an input at least, and also includes the measuring device which has a function which measures an input and performs control based on it.

  According to the present invention, when power is interrupted, required data can be written and protected in a storage medium that does not require power to store and store data. The maximum and minimum values in the data are never lost. In addition, since the protection circuit determines whether or not writing is necessary in comparison with the required data already written in the storage medium before writing the required data in the storage medium, unnecessary writing to the storage medium is performed. Will be avoided.

  In one embodiment of the present invention, the storage medium is a non-volatile memory, and the required data is data of at least one of a maximum value and a minimum value of measurement data.

  According to this embodiment, when a power interruption occurs, it is possible to protect the required data such as the maximum value and the minimum value of the measurement data by writing them into the nonvolatile memory, and unnecessary to the nonvolatile memory. Therefore, the lifetime of the nonvolatile memory can be extended.

  In another embodiment of the present invention, there is provided setting means for selectively setting a protection mode in which the required data is protected and a non-protection mode in which the protection is not performed.

  According to this embodiment, the user can select and set a protected mode in which required data is protected from power interruption or an unprotected mode in which the required data is not protected as necessary.

  In still another embodiment of the present invention, a base board having a plurality of connectors and a plurality of mounting boards detachably attached to the connectors are provided, and the base board is connected to the plurality of connectors. The mounting board has a dedicated circuit corresponding to a function, and the dedicated circuit is connected to the bus wiring by being mounted on the connector. A control circuit is mounted on any of the mounting boards and connected to the bus wiring, and the control circuit identifies a plurality of mounting boards attached to the connector of the base board. It controls to operate as a required model among the models.

  Here, the function means not only functions such as input, output, power supply, and communication, but also functions such as analog input, digital input, output format such as relay output and transistor output, and input / output points. A dedicated circuit refers to a dedicated circuit corresponding to such a function, for example, a circuit such as an input circuit, an output circuit, or a power supply circuit.

  The model refers to the type of device, for example, not only the type of device itself, such as a temperature controller or a digital panel meter, but also the same type of device, for example, a digital panel meter, its upper model or lower model. In addition, for example, types such as the number of input / output points and output format, and other types are included.

  According to this embodiment, the dedicated circuit and the bus wiring are connected to each other by attaching the mounting board having the dedicated circuit corresponding to the function to the connector of the base board having the bus wiring. Since the control circuit mounted on any of the above identifies the mounting board via the bus wiring and operates as a required model, it selects the mounting board having a function according to the required model as the base board. By installing, the required model can be configured. Therefore, between models having the same function, for example, between models having the same relay output function, a mounting board corresponding to the function, for example, a mounting board for relay output can be shared.

  In one embodiment of the present invention, the dedicated circuit includes input, power supply, and output mounting boards each having an input circuit, a power supply circuit, and an output circuit, and the power supply mounting board includes The power interruption detection circuit is mounted, and the protection circuit and the storage medium are mounted on the input mounting substrate.

  According to this embodiment, when power interruption is detected by the power interruption detection circuit mounted on the power supply mounting board, a detection output is output to the protection circuit mounted on the input mounting board via the bus wiring. Given the protection circuit, it is possible to write and protect the required data in the storage medium.

  In a preferred embodiment of the present invention, the power supply backup means for backing up the power supply for a certain period when the power supply is cut off is provided, and the protection circuit responds to the detection output of the power interruption detection circuit. Thus, the operation of at least the output circuit of the output mounting substrate is stopped.

  According to this embodiment, when power interruption is detected, the operation of the output circuit of the mounting board for output is stopped at least, so that the power consumption in the output circuit with relatively large power consumption is eliminated, and the power backup means A sufficient power backup period can be ensured, and the required data can be written to the storage medium using this backup period.

  As described above, according to the present invention, it is possible to avoid the loss of required data, for example, data such as the maximum value and the minimum value, due to a power interruption such as a momentary power failure or a power failure. It is possible to avoid unnecessary data writing to the storage medium.

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

  FIG. 1 is a front view of a digital panel meter as a measuring instrument according to an embodiment of the present invention.

  The digital panel meter 1 has a current value display unit 2 for displaying a current value, a set value display unit 3 for displaying a set value, and a position meter unit 4 for displaying a position of the current value with respect to an arbitrary scale. Are provided with various operation keys such as a MAX / MIN key 5 for switching display values, a level key 6 for switching levels, and a mode key 7 for switching parameters to be displayed. Yes.

  The digital panel meter 1 of this embodiment can store and display the maximum value (MAX value) and the minimum value (MIN value) of the measured values from the time of power-on to the present, as in the conventional example. By operating the MAX / MIN key 5, the current value display unit 2 can switch and display the current value, the maximum value, or the minimum value.

  FIG. 2 is an exploded perspective view of the digital panel meter, and FIG. 3 is a block diagram showing the overall configuration.

  The digital panel meter of this embodiment is a configuration proposed by the present applicant in “Electronic device and method of using electronic device” filed as Japanese Patent Application No. 2002-144490 on May 20, 2002. have.

  That is, the digital panel meter 1 of this embodiment has different specifications and functions such as input / output, power supply, input / output formats such as analog input, digital input, relay output, transistor output, and the number of input / output points. Various substrates are prepared, and necessary substrates are selected and stored in a common case to constitute a required model.

  This makes it possible to share circuit boards between models with different functions compared to the conventional example, which is designed individually for each model and has different types and numbers of circuit boards mounted for each model. It is possible to share the same relay output board among models having a relay output function, thereby reducing costs in design, manufacturing, and management.

  The digital panel meter 1 includes a case 10 composed of a front case 8 and a rear case 9, and the front case 8 includes an operation of a display unit such as the current value display unit 2 and the MAX / MIN key 5 described above. A key is provided.

  The digital panel meter 1 is configured by housing a plurality of module boards 11 to 14 in a case 10. In this embodiment, the digital panel meter 1 includes a front module board 11 as a base board, and the front module board 11. As the plurality of mounting boards to be mounted on the board, an input module board 12, a power supply module board 13, and an output / communication module board 14 are provided.

  Each module substrate 12 to 14 is equipped with a terminal block 15, and a terminal cover 16 is attached so as to cover these terminal blocks 15.

  A front module substrate 11 as a base substrate is housed on the above-described front case 8 side, and for displaying on the current value display unit 2 or the like, as shown in FIG. 3, a liquid crystal cell (LCD) 17, an LCD driver 18, a backlight LED 19 and a display sub CPU 20, and a key switch 21 and a decoder 22 corresponding to various operation keys such as the above-described MAX / MIM key 5.

  Further, the front module board 11 includes bus wiring for connecting the input module board 12, the power supply module board 13, and the output / communication module board 14 to each other via a bus.

The input module board 12 includes a main CPU 23 as a control circuit for controlling the operation of each model of the digital panel meter 1, an input circuit 24 to which an input from a sensor (not shown) is given, and a maximum value as required data as will be described later. And an E ² PROM 25 which is a non-volatile memory as a storage medium in which the minimum value is stored. The input module board 12 is detachably attached to a front module board 11 as a base board via a connector.

  The main CPU 23 of the input module board 12 can control the operation of each model having different specifications such as an output format. The main CPU 23 determines the type of each module board to be mounted on the front module board 11. They are identified as described later and operated as models corresponding to them.

Further, the main CPU 23 of the input module board 12 has a function as a protection circuit, and in the event of a power interruption such as a momentary power failure or a power failure, in response to a power interruption detection signal of the power module board 13, required data The maximum value and minimum value data are stored in the E ² PROM 25 for protection.

  The power supply module board 13 includes a power supply circuit 26 and supplies power to each part. The power supply module board 13 is detachably attached to the front module board 11 serving as a base board via a connector. Accordingly, a necessary power supply module board is selected from the plurality of power supply module boards and mounted on the front module board 11.

  The power supply circuit 26 of the power supply module board 13 is provided with a power interruption detection circuit 38 that detects when power supply is cut off due to an instantaneous power failure or a power failure. As shown in FIG. 4, for example, the power interruption detection circuit 38 of this embodiment includes resistors R1 to R4, a Zener diode ZD, and a transistor TR. The power interruption detection signal 38 detects a decrease in power supply voltage. Is output. In addition, the power supply circuit 26 includes a backup capacitor that backs up the power supply for a certain time after the supply of power is cut off, for example, about several tens of milliseconds.

  The output / communication module substrate 14 includes a serial / parallel conversion circuit 27, an output circuit 28, and a communication circuit 29.

  This output / communication module board 14 is detachably attached to the front module board 11 via a connector, and various outputs such as relay output, current output, transistor open collector output, BCD output, RS-485, A required output / communication module board 14 is selected from a plurality of output / communication module boards that output communication outputs such as RS-232C, and is mounted on the front module board 11.

  The front module board 11 as a base board has a size corresponding to the front case 8, and the front module board 11 is detachably mounted with the input module board 12, the power supply module board 13 and the output / communication module board 14. It has a plurality of connectors as connection parts for doing.

  As described above, the front module board 11 has bus wiring for connecting the module boards. In this embodiment, the front module board 11 has the following bus configuration.

  That is, as shown in FIG. 3, the front module board 11 is a display sub that is a serial bus (UART) for performing data communication between the main CPU 23 of the input module board 12 and the display sub CPU 20 of the front module board 11. A CPU bus 30; a module address bus 40 for an address signal for generating a module select signal for accessing each module substrate; a module select bus 31 for a select signal for accessing each module; A (TYPE) type bus 32 for identifying the type of function of the module board, a UART bus 33 for external communication, a synchronous serial bus 34 for data communication with each module board, and a power supply line 35 are provided. ing. The synchronous serial bus 34 is configured by a plurality, and the power supply line 35 is configured by a plurality of different power supply lines.

  2 and 3 show an example of the configuration of the module substrate, and the number of each module substrate mounted on the front module substrate 11 as the base substrate according to the specifications such as the number of input / output points and the output format. The type and type are appropriately selected. The output / communication module substrate 14 may be separated into an output module substrate and a communication module substrate.

  In the digital panel meter 1 configured by mounting the input module board 12, the power module board 13, and the output / communication module board 14 on the front module board 11 as described above, the main CPU 23 of the input module board 12 When the power is turned on, as will be described later, the types of module boards attached to the connectors of the front module board 11, for example, the module boards attached as the power module board 13 and the output / communication module board 14 The function module board is read in order to identify its type, recognizes the specifications of the output format, input / output points, etc. Control operation suitable for the model is performed.

  Further, as described above, the digital panel meter 1 of this embodiment can store and display the maximum value and the minimum value of the measured values from when the power is turned on to the present time. Even when the power supply is cut off due to a stop or power failure, the maximum value and the minimum value are not lost if the user desires.

  In other words, this embodiment is configured so that the power interruption write mode as a protection mode for storing the maximum value and the minimum value can be set by operating the operation keys even when the power interruption occurs.

When the power interruption write mode is set, the main CPU 23 of the input module board 12 sets the maximum value and the minimum value to the E ² PROM 25 in response to the power interruption detection signal from the power interruption detection circuit 38 of the power module board 13. I write and protect it.

  FIG. 5 is a flowchart of the measurement process after the power is turned on.

  First, when the power is turned on, as described above, the main CPU 23 of the input module board 12 sequentially reads and identifies the types of module boards attached to the connectors of the front module board 11 as the base board. (Step n1). Identification of the type of the module substrate is performed as described later using the module select bus 31 and the type bus 32 described above. The type of the front module substrate 11 is determined by serial communication with the display sub CPU 20.

  As a result, the main CPU 23 can recognize the specifications of the input / output format, the number of input / output points, etc., determine the model, move to step n3, and perform measurement processing corresponding to the model. Start (step n2).

In step n3, the internal variable is initialized, the data written in the E ² PROM 25 is read, measurement is started to obtain the measured value (step n4), and whether or not the interruption write mode is set. (Step n5), and when the interruption write mode is not set, the acquired measurement value is set to the MAX value (maximum value) and the MIN value (minimum value) is transferred to step n8 (step n6).

In step n5, when the power interruption write mode is set, the registered MAX value already written in the E ² PROM 25 is set as the MAX value, and the registered MIN value already written in the E ² PROM 25 is set as the MIN value. The process proceeds to step n8 (step n7).

  In step n8, the measured value is acquired, and it is determined whether or not the measured value is larger than the MAX value (step n9). If not larger, the process proceeds to step n11. The processing proceeds to step n11 as the MAX value (step n10).

  In step n11, it is determined whether or not the acquired measurement value is smaller than the MIN value. If it is not smaller, the process proceeds to step n13. If it is smaller, the acquired measurement value is moved to step n13 as a new MIN value. The measurement process is performed and the process returns to step n8 (step n12).

When the power is turned on in this way, the maximum value and minimum value already written in the E ² PROM 25 or the acquired measured value is set to the maximum value depending on whether or not the power interruption write mode is set. And it is updated and stored in a RAM (not shown) of the input module board 12 as a minimum value.

  FIG. 6 is a flowchart for explaining the operation when a power interruption such as a momentary power failure or a power failure occurs during the measurement process.

First, when a power interruption is detected, it is determined whether or not a power interruption write mode is set (step n20). If it is set, the E ² PROM write flag is turned off (step n21), and E ^{2 is set.} It is determined whether or not the MAX value registered in the PROM 25 is smaller than the current MAX value stored in the RAM (step n22). If not, the process proceeds to step n24. it ^is, is larger than the MAX value registered in the E 2 PROM ^25, moves to step n24 to turn on the ^E 2 PROM write flag as a registered MAX value to be written to the E 2 PROM 25 (step n23).

In step n24, it is determined whether or not the MIN value registered in the E ² PROM 25 is larger than the current MIN value stored in the RAM. If not, the process proceeds to step n26. write ^value, is smaller than the MIN value registered in the E 2 PROM ^25, moves to step n26 to turn on the ^E 2 PROM write flag as a registered MIN value to be written to the E 2 PROM 25 (step n25).

In step n26, it is determined whether or not the E ² PROM write flag is turned on. If it is not turned on, the process proceeds to step n28. If it is turned on, the MAX corresponding to the E ² PROM write flag turned on is determined. The value or MIN value is written and registered in the E ² PROM 25 (step n27), and the process proceeds to step n28.

  In step n28, another power interruption process is performed and a reset standby state is entered (step n29).

As described above, when a power interruption such as a momentary power failure occurs while the power interruption write mode is set, the current MAX value and MIN value stored in the RAM are stored in the E ² PROM 25. Compare with the registered MAX value and registered MIN value that have already been written. When the current MAX value is larger than the registered MAX value or when the current MIN value is smaller than the registered MIN value, writing to the E ² PROM 25 is performed. As a result, unnecessary writing can be avoided and the life of the E ² PROM 25 can be extended, and the MAX value and the MIN value are not lost by power interruption.

  Next, determination of the presence / absence of mounting of another module substrate on the front module substrate 11 as a base substrate and identification of each mounted module substrate will be described with reference to FIGS.

  First, as shown in FIG. 7, the main CPU 23 of the input module board 12 uses a 4-bit module address signal as a selection signal for sequentially selecting a plurality of (11 in this example) connectors of the front module board 11. MA0 to MA3 are output to the decoder 22 shown in FIG. 3 of the front module board 11, and the decoder 22 decodes the module address signal and designates one of the module boards corresponding to the plurality of connectors. As shown in FIG. 8, the transistor 36 on the corresponding module substrate is turned on by the MS signal that outputs the signal and inverts the signal. Each module substrate has a plurality of diodes 37 that are turned on when the transistor 36 is turned on, and the number of the diodes 37 corresponds to the type, that is, the function of the module substrate.

  Therefore, the type signals TYPE0 to TYPE6 as identification signals corresponding to the number of diodes 37 of the module board mounted on the designated connector are given to the main CPU 23 via the type bus 32, whereby the main CPU 23 Thus, it is possible to determine whether or not the module board is mounted on the designated connector, and to identify the type of the mounted module board.

  As described above, the type of each module board such as input, power supply and output / communication can be identified and operated as a corresponding model, so between models having the same function, for example, the same relay output function It is possible to share the same relay output module board among models with the same design, which reduces design costs, simplifies assembly, and makes it the same as compared to designing each model individually. The cost can be reduced by increasing the mass production quantity of the substrate.

(Other embodiments)
As another embodiment of the present invention, when power interruption is detected, for example, the operation of an output circuit or the like of the output module substrate may be stopped to suppress power consumption.

  The present invention can be suitably applied not only to a digital panel meter but also to a device that measures input, for example, a temperature controller that measures temperature and performs control based on the measured temperature.

  In the above-described embodiment, the maximum value and the minimum value are written in the non-volatile memory at the time of power interruption. However, not only the maximum value and the minimum value but also parameters may be written.

In the above-described embodiment, E ² PROM is used as the nonvolatile memory. However, the present invention is not limited to the E ² PROM, and may be a flash memory or the like. A card or the like may be used.

  The present invention is useful as a measuring instrument for measuring various inputs.

It is a front view of the digital panel meter which concerns on one embodiment of this invention. It is a disassembled perspective view of the digital panel meter of FIG. It is a block diagram which shows the circuit structure of the digital panel meter of FIG. FIG. 4 is a configuration diagram of a power interruption detection circuit of FIG. 3. It is a flowchart with which operation | movement description of measurement processing is provided. It is a flowchart with which it uses for operation | movement description at the time of a power failure. It is a figure which shows the production | generation of the module select signal for identification of a module board. It is a figure which shows the production | generation of the type signal for the identification of a module board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital panel meter 2 Present value display part 5 MAX / MIN key 11 Front module board 12 Input module board 13 Power supply module board 14 Output / communication module board 23 Main CPU
25 E ² PROM

Claims (6)

A measuring device that measures input,
A power interruption detection circuit for detecting that the supply of power has been cut off, a storage medium that does not require power for storing data, and a storage medium that receives required data in response to a detection output of the power interruption detection circuit And a protection circuit for protecting the required data by writing to
The protection circuit compares the required data with the required data already written to the storage medium before writing the required data to the storage medium, and whether or not writing to the storage medium is necessary. Measuring instrument characterized by determining. The storage medium is a non-volatile memory;
The measuring device according to claim 1, wherein the required data is at least one of a maximum value and a minimum value of measurement data.   The measuring device according to claim 1, further comprising a setting unit that selectively sets a protection mode for protecting the required data and a non-protection mode for which the protection is not performed. A base board having a plurality of connectors, and a plurality of mounting boards detachably attached to the connectors,
The base substrate has bus wiring connected to the plurality of connectors, and the mounting substrate has a dedicated circuit corresponding to a function, and the dedicated circuit is mounted on the connector so that the dedicated circuit is connected to the bus wiring. Connected to the
A control circuit mounted on either the base substrate or the mounting substrate and connected to the bus wiring,
4. The control circuit according to claim 1, wherein the control circuit identifies a mounting board that is mounted on the connector of the base board, and controls to operate as a required model among a plurality of models. 5. Measuring equipment. The dedicated circuit includes an input circuit, a power supply circuit, and an output circuit each having a mounting board for input, power supply, and output, respectively.
The power interruption detection circuit is mounted on the power supply mounting board,
The measuring instrument according to claim 4, wherein the protection circuit and the storage medium are mounted on the input mounting substrate. Power supply backup means for backing up the power supply for a certain period when the power supply is cut off,
6. The measuring device according to claim 5, wherein the protection circuit stops the operation of at least the output circuit of the mounting board for output in response to the detection output of the power interruption detection circuit.

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