JP2009290373A - A/d converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an A/D converter capable of being miniaturized even while preventing noise intrusion. <P>SOLUTION: The A/D converter includes: two A/D conversion blocks CB provided with a signal selection part 2 for selecting one from a plurality of inputted analog signals and outputting it and an A/D conversion part 3 for preparing digital data from the analog signal outputted from the signal selection part 2; and a data transfer block TB for outputting the digital data to an external apparatus MB. To a transmission path between the A/D conversion block CB and the data transfer block TB, an insulated transmitter 8 for transmitting data between an input end and an output end electrically insulated from each other is inserted. Each A/D conversion block CB is provided with an operation processing part 4 for executing: signal selection processing of controlling the signal selection part 2 so as to output a desired analog signal; and data output processing of transmitting the digital data prepared in the A/D conversion part 3 to the data transfer block TB by the insulated transmitter 8. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an A / D conversion device.

  Conventionally, a programmable controller that sequentially controls the operation of a load device has been provided. As such a programmable controller, there are proposed ones in which various functional units such as a CPU unit and a power supply unit are mounted on the motherboard, and those in which various functional units are mounted on the control unit. It can be used for various purposes depending on the combination of the unit to be used and the functional unit attached to the control unit. For example, the programmable controller is also used for various feedback controls. In this case, in order to take in an analog signal indicating temperature or the like from a sensor or the like, an A / D that converts the analog signal into digital (digital) data. A conversion device (A / D conversion unit) is used.

  As this type of A / D converter, for example, the one shown in FIG. 3 has been proposed. The A / D converter shown in FIG. 3 is mainly output from an analog signal input unit 1 to which a plurality of analog signals are input, a signal selection unit 2 connected to the analog signal input unit 1, and the signal selection unit 2. Two A / D conversion blocks CB having an A / D conversion unit 3 that quantizes the analog signal to create digital data (distinguished by reference numerals CB1 and CB2 as necessary), and an A / D conversion device An arithmetic processing unit 4 that performs overall control and a data transfer block TB that includes a buffer storage unit 5 that temporarily stores digital data created by each A / D conversion block CB.

  The analog signal input unit 1 is configured by a device that outputs an analog signal, for example, a terminal block including a plurality of wire connection terminals (not shown) for connecting wires of various sensors. In the A / D conversion device shown in FIG. 3, the analog signal input unit 1 includes a plurality of wire connection terminals for the A / D conversion block CB1 and a plurality of wire connection terminals for the A / D conversion block CB2. It is possible to simultaneously capture up to two isolated analog signals.

  The signal selection unit 2 includes a multiplexer having a plurality of switches SW that are alternatively set to ON. Each of the plurality of switches SW of the signal selection unit 2 is individually connected to each of the plurality of wire connection terminals for the A / D conversion block CB in the analog signal input unit 1. Further, the signal selection unit 2 selects one of the analog signals input to the analog signal input unit 1 and outputs it by setting any switch SW to ON based on the input selection signal.

  The A / D conversion unit 3 includes an A / D converter that quantizes an input analog signal to create digital data having a predetermined number of bits (for example, 16 bits). The A / D converter 3 has an input terminal (not shown) for inputting an analog signal, an output terminal for outputting digital data, and a clock terminal (not shown) for inputting a clock signal. A conversion start terminal (not shown) to which a conversion start signal is input is provided. Therefore, the A / D conversion unit 3 takes in an analog signal based on the clock signal, and creates and outputs digital data from the taken-in analog signal when the conversion start signal is inputted.

  Incidentally, the A / D conversion device shown in FIG. 3 is provided with a signal amplification unit 6 that amplifies the analog signal selected by the signal selection unit 2 with a predetermined amplification factor and outputs the amplified signal to the A / D conversion unit 3. The signal amplifying unit 6 includes a variable amplifying unit 6a composed of a variable amplifier capable of changing the amplification factor of the analog signal, and an amplification factor switching unit 6b that changes the amplification factor in the variable amplifying unit 6a according to the amplification factor setting signal. Is done.

  The selection signal, clock signal, conversion start signal, and amplification factor setting signal described above are supplied from the arithmetic processing unit 4 of the data transfer block TB. In the A / D conversion device shown in FIG. 3, the A / D conversion block CB is provided with a data conversion unit 7 including a serial / parallel converter that converts a serial signal into a parallel signal and outputs the parallel signal. The selection signal and the amplification factor setting signal converted into the parallel format by the data converter 7 are input to the signal selection unit 2 and the amplification factor switching unit 6b.

  The arithmetic processing unit 4 includes a CPU that executes a program stored in a memory, and includes a microcomputer (microcontroller, abbreviated as a microcomputer, also referred to as a CPU in a broad sense) that executes various processes. The processing executed by the arithmetic processing unit 4 mainly selects signals so that a desired analog signal is output from the signal selection unit 2 in accordance with an input of an input switching unit (not shown) provided in the data transfer block TB. A process (signal selection process) for controlling the unit 2 (outputting a selection signal), a clock signal and a conversion start signal are output for acquiring digital data from the A / D conversion unit 3, and the acquired digital data is stored in the storage unit 5 (data output processing) and processing for setting the amplification factor in the signal amplifier 6 (outputting an amplification factor setting signal) (amplification factor setting processing).

  Two storage units 5 are provided in the data transfer block TB, and are used as a shared memory or data buffer with an external device (for example, the above-described mother board or control unit) MB. Hereinafter, as necessary, a storage unit that stores digital data of the A / D conversion block CB1 is denoted by reference numeral 5A, and a storage unit that stores digital data of the A / D conversion block CB2 is denoted by reference numeral 5B.

  The storage unit 5 is connected to the external device MB via a data bus (for example, an I / O bus), and digital data is transmitted through the data bus in response to a request from the external device MB. Such a storage unit 5 includes, for example, a data buffer 50H that stores a higher-order bit string of digital data created by the A / D conversion block CB, and a data buffer 50L that stores a lower-order bit string of digital data. Consists of. As a specific example, an 8-bit shift register can be cascade-connected to store 16-bit digital data.

  In the example shown in FIG. 3, the arithmetic processing unit 4 outputs a serial-format signal indicating the digital data of the A / D conversion block CB to the storage unit 5A and also to the storage unit 5B via the storage unit 5A. . Therefore, the arithmetic processing unit 4 outputs the digital data of the A / D conversion blocks CB1 and CB2 to the storage units 5A and 5B as serial format signals (in the configuration shown in FIG. 3, the A / D conversion block CB2 The upper 8 bits and lower 8 bits of the digital data are output in the order of the upper 8 bits and the lower 8 bits of the digital data of the A / D conversion block CB1). In addition, the arithmetic processing unit 4 individually outputs a clock signal for writing and a latch (latch clock) signal indicating the end of writing to both the data buffers 50H and 50L of the respective storage units 5A and 5B. Data stored in the storage unit 5 can be read from the external device MB. Thereby, the digital data of the A / D conversion block CB1 is stored in the storage unit 5A, and the digital data of the A / D conversion block CB2 is stored in the storage unit 5B.

  By the way, in the A / D conversion device shown in FIG. 3 described above, the noise of the A / D conversion block CB on the input side (side connected to a sensor or the like that outputs an analog signal) is output side (reads digital data). It is important to prevent intrusion into the data transfer block TB which is the side connected to the external device MB or the like, and conversely, prevent noise from the data transfer block TB from entering the A / D conversion block CB.

  Therefore, in such an A / D converter, in order to electrically insulate between the A / D conversion block CB and the data transfer block TB, between the A / D conversion block CB and the data transfer block TB. Conventionally, it has been proposed to insert an insulated transmission device 8 (see FIG. 3) into the transmission line (see, for example, Patent Document 1).

  Such an insulated transmission device 8 performs data transmission between an input end and an output end that are electrically insulated from each other. For example, an electrical signal indicating digital data is converted into an optical signal and transmitted. Insulated signal transmission parts such as photocouplers.

In the A / D conversion device shown in FIG. 3, the insulated transmission device 8 is inserted in a transmission path for transmitting digital data from the A / D conversion block CB to the data transfer block TB. In addition, a transmission path for transmitting a selection signal from the arithmetic processing unit 4 to the signal selection unit 2, a transmission path for transmitting an amplification factor setting signal from the arithmetic processing unit 4 to the signal amplification unit 6, and the arithmetic processing unit 4 Insulating transmission device 8 is also inserted into two transmission paths for individually transmitting a clock signal and a conversion start signal to A / D conversion unit 3. That is, in the A / D conversion device shown in FIG. 3, five insulated transmission devices 8 are provided for each A / D conversion block CB.
JP-A-7-58638

  By the way, as shown in FIG. 4, the A / D conversion apparatus as described above has predetermined components (electronic components) constituting the signal selection unit 2, the A / D conversion unit 3, the arithmetic processing unit 4, and the like. Are mounted on a printed circuit board P on which a wiring pattern (not shown) is formed. In FIG. 4, only a schematic diagram of electronic components corresponding to the signal selection unit 2, the A / D conversion unit 3, the arithmetic processing unit 4, the data conversion unit 7, and the insulated transmission device 8 is shown for simplification of explanation. The printed circuit board P is shown in a simplified manner.

  In order to ensure good insulation between the A / D conversion block CB and the data transfer block TB when mounting the electronic components constituting the A / D conversion device on such a printed circuit board P, A / D The electronic components and wiring patterns constituting the conversion block CB and the electronic components and wiring patterns constituting the data transfer block TB are mounted on the printed circuit board P with an insulating gap.

  Therefore, the printed circuit board P is provided with a component mounting area CA for the A / D conversion block CB and a component mounting area TA for the data transfer block TB. Hereinafter, the component mounting area for the A / D conversion block CB1 is denoted by reference sign CA1 and the component mounting area for the A / D conversion block CB2 is denoted by reference sign CA2 as necessary.

  In the A / D conversion device shown in FIG. 3, since it is necessary to provide five insulating transmission devices 8 for each A / D conversion block CB, between the component mounting area CA1 and the component mounting area TA, and the component mounting The insulated transmission devices 8 are arranged in a straight line between the area CA2 and the component mounting area TA. As a result, as shown in FIG. 4, a total of ten insulated transmission apparatuses 8 are arranged side by side.

  Here, when a photocoupler is used as the insulated transmission device 8, the photocoupler is a package of a light emitting diode and a photodiode that receives light emitted from the light emitting diode so that the light of the light emitting diode does not leak outside. Therefore, the area occupied by the insulated transmission device 8 on the printed circuit board P is much larger than that of an electric signal transmission path constituted by a wiring pattern of the printed circuit board P or the like. growing.

  Therefore, when the insulated transmission device 8 is inserted into the transmission path between the A / D conversion block CB and the data transfer block TB for the purpose of preventing noise from entering, a region for mounting the insulated transmission device 8 is printed. It must be secured on the board P (the component mounting area of the printed board P must be increased), resulting in an increase in the size of the printed board P, which contributes to an increase in the size of the A / D converter. It was.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an A / D conversion device that can be reduced in size while preventing intrusion of noise.

  In order to solve the above problems, in the invention of claim 1, a signal selection unit that selects and outputs one of the analog signals input to the analog signal input unit to which a plurality of analog signals are input, and the signal An A / D conversion block having an A / D conversion unit that generates digital data by quantizing an analog signal selected by the selection unit, and digital data created by the A / D conversion block are temporarily stored. A data transfer block that has a buffer storage unit and outputs digital data stored in the storage unit to an external device, and is electrically connected to a transmission path between the A / D conversion block and the data transfer block. An A / D converter in which an isolated transmission device for transmitting data between an input terminal and an output terminal isolated from each other is inserted, and a desired analog signal is selected in the A / D conversion block. An arithmetic processing unit is provided for executing signal selection processing for controlling the signal selection unit so that the data is output and data output processing for transmitting the digital data created by the A / D conversion unit to the storage unit by the insulated transmission device. It is characterized by being.

  According to the first aspect of the present invention, since the arithmetic processing unit is provided not in the data transfer block but in the A / D conversion block, the signal selection unit and the arithmetic operation required when the arithmetic processing unit is provided in the data transfer block. The need for an insulated transmission device between the processing units is eliminated, and the number of insulated transmission devices required can be reduced compared to the case where the arithmetic processing unit is provided in the data transfer block, thereby reducing the component mounting area of the printed circuit board. Therefore, it is possible to reduce the size of the printed circuit board. As a result, it is possible to reduce the size of the printed circuit board while preventing intrusion of noise.

  According to a second aspect of the invention, in the first aspect of the invention, the A / D conversion block amplifies the analog signal selected by the signal selection unit with a predetermined amplification factor and outputs the amplified signal to the A / D conversion unit. The signal processing unit includes a signal amplification unit, and the arithmetic processing unit executes amplification factor setting processing for setting an amplification factor in the signal amplification unit according to the type of the analog signal selected by the signal selection unit.

  According to the second aspect of the present invention, an analog signal can be amplified with an amplification factor suitable for the type, and there is no need to provide an insulated transmission device in the transmission path between the arithmetic processing unit and the signal amplification unit. The component mounting area of the printed circuit board can be reduced, and the size can be reduced.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the arithmetic processing unit outputs the digital data created by the A / D conversion unit according to the type of the analog signal selected by the signal selection unit. A conversion process for converting into digital data suitable for the process in the external device is executed.

  According to the invention of claim 3, since the user or the like does not have to perform the process of converting the digital data into the digital data suitable for the process in the external device, the usability is improved.

  The present invention has an effect that it is possible to reduce the size while preventing intrusion of noise.

  As shown in FIG. 1, the A / D converter according to an embodiment of the present invention selects and outputs one analog signal input to an analog signal input unit 1 to which a plurality of analog signals are input. Two A / D conversion blocks CB each including a selection unit 2 and an A / D conversion unit 3 that quantizes the analog signal selected by the signal selection unit 2 to create digital data, and each A / D conversion A buffer storage unit 5 for temporarily storing digital data created in the block CB, and two data transfer blocks TB for outputting the digital data stored in the storage unit 5 to the external device MB. In the following description, the two A / D conversion blocks CB are denoted by reference numerals CB1 and CB2 as necessary to distinguish between the two A / D conversion blocks CB. In order to distinguish the two data transfer blocks TB, they are denoted by reference numerals TB1 and TB2 as necessary. To express.

  The analog signal input unit 1 in the present embodiment includes a terminal block including a plurality of wire connection terminals (not shown) that connect wires of various sensors. Here, the various sensors are, for example, temperature sensors. In the A / D converter according to the present embodiment, a K-type thermocouple (hereinafter referred to as sensor A) and a J-type thermocouple (hereinafter referred to as sensor B). Temperature sensor (hereinafter referred to as sensor C) using platinum or the like, or a temperature sensor (hereinafter referred to as sensor D) such as a cold junction temperature sensor that generates a direct current or direct current voltage having a magnitude corresponding to the detected temperature. ) Can be used. Also in this embodiment, the analog signal input unit 1 includes a plurality of wire connection terminals for the A / D conversion block CB1 and a plurality of wire connection terminals for the A / D conversion block CB2, and has a maximum of two insulations. It is possible to simultaneously take in analog signals. That is, the A / D conversion device of this embodiment has two channels for taking in analog signals.

  As shown in FIG. 1, the A / D conversion block CB in the present embodiment includes a signal amplifying unit 6, an arithmetic processing unit 4, and an input switching unit 9 in addition to the signal selection unit 2 and the A / D conversion unit 3. With. The signal selection unit 2, the A / D conversion unit 3, and the signal amplification unit 6 are the same as those in the conventional example shown in FIG. The signal selection unit 2, the A / D conversion unit 3, and the signal amplification unit 6 are not limited to those described above, and other conventionally known ones can be employed.

  The input switching unit 9 is for switching an analog signal output from the signal selection unit 2 (that is, a sensor to be used), and is configured by, for example, a two-pole DIP switch.

  The arithmetic processing unit 4 according to the present embodiment includes a CPU that executes a program stored in a memory as in the case shown in FIG. 3 and includes a microcomputer that executes various processes. However, the processing contents are different. .

  In the arithmetic processing unit 4 in the present embodiment, a desired analog signal (that is, an analog signal output from the desired sensors A to D) is a signal in accordance with the input of the input switching unit 9 (that is, on / off of the DIP switch). Processing (signal selection processing) for controlling the signal selection unit 2 (outputting the selection signal) so as to be output from the selection unit 2 is executed.

  For example, a combination of on / off of the DIP switch of the input switching unit 9 and the sensors A to D are related, and the combination of on / off of the DIP switch of the input switching unit 9 detected by the arithmetic processing unit 4 is the sensor. If the combination corresponds to A, a selection signal is output to the signal selection unit 2 so as to select an analog signal corresponding to the sensor A.

  As an example of the relationship between the combination of ON / OFF of the DIP switch of the input switching unit 9 and the sensors A to D, if both switches of the input switching unit 9 are OFF, only the sensor A is ON. If there is a sensor B, if only the other switch is on, the sensor C is considered. If both switches are on, the sensor D is considered.

  In addition, the arithmetic processing unit 4 executes a process (amplification factor setting process) for setting the amplification factor in the signal amplifying unit 6 according to the input of the input switching unit 9. For example, in the A / D conversion device of the present embodiment, the amplification factor is set corresponding to each of the sensors A to D, and the arithmetic processing unit 4 is based on the input of the input switching unit 9 to determine the amplification factor setting signal. Is output to the amplification factor switching unit 6b to change the amplification factor in the variable amplification unit 6a. This is because the difference in the magnitude of the analog signal in the sensors A to D (for example, the range of the voltage value) is taken into account. Thus, by setting the amplification factor to a value suitable for the sensors A to D, the resolution can be reduced. Improvements can be made.

  Further, the arithmetic processing unit 4 outputs a clock signal and a conversion start signal to the A / D conversion unit 3 in order to acquire digital data from the A / D conversion unit 3, and the acquired digital data is stored in the storage unit 5. The process to transmit to (data output process) is executed. During this processing, the arithmetic processing unit 4 is created by the A / D conversion unit 3 in accordance with the input of the input switching unit 9, that is, in accordance with the type of analog signal (sensor type) selected by the signal selection unit 2. A process of converting the converted digital data into digital data suitable for the process in the external device MB (conversion process) is executed. The arithmetic processing unit 4 transmits the digital data to the storage unit 5 after performing the conversion process.

  For this reason, the storage unit 5 in this embodiment stores digital data that has been converted by the arithmetic processing unit 4 into a form suitable for processing in the external device MB.

  For example, when the digital data created by the A / D conversion unit 3 is digital data obtained by linearly converting the magnitude of an analog signal, the digital data handled by the external device MB is digital data obtained by logarithmically converting the analog signal. In the case of data, the arithmetic processing unit 4 converts the analog signal into logarithmically converted digital data based on the digital data created by the A / D conversion unit 3. The content of the conversion performed by the arithmetic processing unit 4 may be set to a suitable one according to the type of the A / D conversion unit 3, the type of the sensor, and the type of the external device MB, and is not limited to the above example. . If the digital data created by the A / D conversion unit 3 is a straight binary code and the digital data handled by the external device MB is an offset binary code, the arithmetic processing unit 4 The data format of the digital data created by the A / D converter 3 is converted from a straight binary code to an offset binary code. Note that the data format to be converted by the arithmetic processing unit 4 may be set to a suitable one according to the type of the A / D conversion unit 3, the type of sensor, and the type of the external device MB. Various data formats that can be handled by the external device MB, such as 1's complement code, 2's complement code, and Gray code, can be used without being limited to codes and offset binary codes.

  As described above, in the A / D conversion device of the present embodiment, since the arithmetic processing unit 4 executes the conversion processing, a user or the like performs processing for converting digital data into a data format suitable for processing in the external device MB. Since it is not necessary to do so, usability is improved.

  The A / D conversion device of the present embodiment has two data transfer blocks TB, and a storage unit 5 is provided in each of the two data transfer blocks TB1 and TB2. Here, the storage unit 5 of the data transfer block TB1 (hereinafter denoted by reference numeral 5A as necessary) is used for storing digital data of the A / D conversion block CB1, and the storage unit 5 of the data transfer block TB2 (hereinafter required). Is represented by reference numeral 5B) for use in storing digital data of the A / D conversion block CB2. Such a storage unit 5 includes, for example, a data buffer 50H that stores a higher-order bit string of digital data created by the A / D conversion block CB, and a data buffer 50L that stores a lower-order bit string of digital data. Consists of. As a specific example, an 8-bit shift register can be cascade-connected to store 16-bit digital data. In the data output process, the arithmetic processing unit 4 outputs a serial signal indicating the digital data of the A / D conversion block CB to the storage unit 5 and transmits the digital data to the storage unit 5. The write clock signal and the latch clock signal indicating the end of writing are individually output to both of the data buffers 50H and 50L, thereby enabling the data stored in the storage unit 5 to be read from the external device MB.

  Also in the A / D conversion device of this embodiment, in order to electrically insulate between the A / D conversion block CB and the data transfer block TB and prevent intrusion of noise, the A / D conversion block CB and the data The insulated transmission device 8 is inserted into the transmission path between the transfer block TB. The insulated transmission device 8 is the same as that shown in FIG. 3, and is a photocoupler as an example. However, the insulated transmission device 8 is not limited to a photocoupler, and may be an isolator or a pulse transformer. In short, data transmission is performed between an input end and an output end that are electrically insulated from each other. Anything is acceptable.

  In the A / D conversion device according to the present embodiment, as shown in FIG. 1, a transmission path between the arithmetic processing unit 4 and the storage unit 5, that is, a serial format corresponding to digital data output from the arithmetic processing unit 4. Insulated transmission device 8 (indicated by reference numeral 8A if necessary) is inserted into the transmission path for the signal, and isolated transmission apparatus 8 (indicated by reference numeral 8B if necessary) is inserted in the transmission path for the clock signal for writing. The insulated transmission device 8 (indicated by reference numeral 8C as necessary) is inserted into the transmission path for the latch clock signal indicating the end of writing.

  As described above, the A / D converter according to the present embodiment includes the signal selection unit 2 that selects and outputs one of the analog signals input to the analog signal input unit 1 to which a plurality of analog signals are input, A plurality of (two in the illustrated example) A / D conversion blocks CB having an A / D conversion unit 3 that quantizes the analog signal selected by the signal selection unit 2 to create digital data, and A / D conversion A plurality of (two in the illustrated example) data that has a buffer storage unit 5 for temporarily storing the digital data created in the block CB and outputs the digital data stored in the storage unit 5 to the external device MB An insulated transmission device 8 that includes a transfer block TB and performs data transmission between an input end and an output end that are electrically insulated from each other is inserted into a transmission path between the A / D conversion block and the data transfer block. Have been In each A / D conversion block CB, signal selection processing for controlling the signal selection unit 2 so that a desired analog signal is output from the signal selection unit 2, and digital data created by the A / D conversion unit 3 Is provided with an arithmetic processing unit 4 that executes data output processing for transmitting the data to the storage unit by the insulated transmission device 8.

  Next, the operation of the A / D conversion device of this embodiment will be briefly described. As a previous step, a sensor is connected to the analog signal input unit 1. Here, when the sensor A is connected to a plurality of wire connection terminals for the A / D conversion block CB1 in the analog signal input unit 1, the combination of the DIP switches of the input switching unit 9 of the A / D conversion block CB1 is detected as a sensor. A combination corresponding to A is used. As a result, the arithmetic processing unit 4 of the A / D conversion block CB1 executes the selection process and the amplification factor setting process described above, and the signal selection unit 2 can output an analog signal corresponding to the sensor A. The amplification factor in the amplification unit 6 is set to the amplification factor corresponding to the sensor A.

  Thereafter, the arithmetic processing unit 4 executes the above-described data output process, whereby the digital data created by the A / D conversion unit 3 of the A / D conversion block CB1 is input to the arithmetic processing unit 4 and the above-described data output processing is performed. After the data format is converted by the conversion process, the data format is output to the storage unit 5A of the data transfer block TB1. The digital data output from the arithmetic processing unit 4 is transmitted to and stored in the storage unit 5A via the insulated transmission devices 8A to 8C. The digital data stored in the storage unit 5A is read by the external device MB, whereby the analog signal output from the sensor A is taken into the external device MB as digital data.

  The operation described above is performed in the same manner even when a sensor is connected to a plurality of wire connection terminals for the A / D conversion block CB2 in the analog signal input unit 1, and a plurality of wire connections for the A / D conversion block CB2 are performed. An analog signal input from a sensor connected to the terminal is converted into digital data and stored in the storage unit 5B. Therefore, since the A / D conversion device of this embodiment includes two sets of the A / D conversion block CB and the data transfer block TB, two analog signals are simultaneously output to the external device MB as digital data. It is possible.

  The A / D conversion apparatus according to the present embodiment as described above is also configured by mounting various electronic components on a printed circuit board P on which a predetermined wiring pattern (not shown) is formed, as shown in FIG. The Here, when mounting various electronic components on the printed circuit board P, in order to ensure good insulation between the A / D conversion block CB and the data transfer block TB, the printed circuit board P has an A / D A component mounting area CA for the D conversion block CB and a component mounting area TA for the data transfer block TB are provided. In FIG. 2, only a schematic diagram of electronic components corresponding to the signal selection unit 2, the A / D conversion unit 3, the arithmetic processing unit 4, and the insulated transmission device 8 is illustrated for the sake of simplicity of explanation. . Further, as necessary, a component mounting area for the A / D conversion block CB1 is denoted by reference sign CA1, and a component mounting area for the A / D conversion block CB2 is denoted by reference sign CA2.

  In this case, as shown in FIG. 2, the insulated transmission device 8 is arranged in a straight line between the component mounting area CA1 and the component mounting area TA and between the component mounting area CA2 and the component mounting area TA. However, in the A / D conversion device of the present embodiment, the arithmetic processing unit 4 is provided not in the data transfer block TB but in the A / D conversion block CB, so that the A / D of the conventional example shown in FIG. Between the signal selection unit 2 and the calculation processing unit 4 and between the signal amplification unit 6 and the calculation processing unit 4 that are necessary when the calculation processing unit 4 is provided in the data transfer block TB as in the conversion device. The insulated transmission device 8 becomes unnecessary, and the required number of the insulated transmission devices 8 can be reduced as compared with the case where the arithmetic processing unit 4 is provided in the data transfer block TB. In particular, in the case of the present embodiment, as shown in FIG. 2, the number of insulated transmission devices 8 required for one A / D conversion block CB can be reduced by two compared to the conventional example shown in FIG. Can be reduced by four.

  Therefore, according to the A / D conversion device of the present embodiment, the component mounting area of the printed circuit board P can be reduced, and the printed circuit board P can be downsized. As a result, noise can be prevented from entering. While achieving this, it is possible to reduce the size.

  By the way, since the A / D conversion device of this embodiment includes two A / D conversion blocks CB, it has two arithmetic processing units 4, and the conventional A / D conversion device shown in FIG. Compared to, the number of arithmetic processing units 4 is increased. Conventionally, the CPU used for the arithmetic processing unit 4 has been expensive and large in size. However, in recent years, the CPU has been reduced in cost and size, and the CPU of the arithmetic processing unit 4 is low in cost. Therefore, a package with a small mounting area can be used. Therefore, even if the number of arithmetic processing units 4 increases, there is no significant problem because the cost and mounting area do not increase significantly.

  In addition, by providing the arithmetic processing unit 4 in the A / D conversion block CB, the selection signal and the amplification factor setting signal may be output from the arithmetic processing unit 4 in parallel format instead of serial format. The number of 8 does not increase, and conversely, by outputting the selection signal and the amplification factor setting signal in parallel format, the data conversion unit 7 (see FIG. 3) is not required, so that the mounting area of the component is further reduced. And further downsizing can be achieved. Furthermore, since it is not necessary to provide the insulated transmission device 8 in the transmission path between the A / D conversion unit 3 and the arithmetic processing unit 4, the A / D conversion unit 3 and the arithmetic processing unit 4 are integrally formed ( For example, it can be integrated as an IC), and further miniaturization is possible.

  In addition, since the arithmetic processing unit 4 is provided for each A / D conversion block CB, the processing content can be set for each A / D conversion block CB. Therefore, by providing a plurality of sets of A / D conversion blocks CB and data transfer blocks TB, it is possible to easily realize multi-channel. Moreover, the function can be easily expanded by rewriting the program stored in the memory of the arithmetic processing unit 4. In addition, since the data transfer block TB does not have to be shared by a plurality of A / D conversion blocks CB as in the conventional example shown in FIG. 3, insulation between channels (ie, insulation between A / D conversion blocks CB). ) And the processing time in the arithmetic processing unit 4 can be prevented from becoming long when the number of channels is increased because the processing is not concentrated on one arithmetic processing unit 4. Further, since the A / D conversion block CB and the data transfer block TB can be used as a single device, it can be easily transferred to various other devices.

  Note that the configuration of the A / D conversion device of the present embodiment is merely an embodiment of the present invention, and the technical scope of the present invention is not limited to the above example, but is changed to the extent that does not depart from the spirit. be able to. For example, although the A / D conversion apparatus of the present embodiment includes two A / D conversion blocks CB, the number of A / D conversion blocks CB may be one or three or more. May be. Further, although a temperature sensor is illustrated as a sensor connected to the analog signal input unit 1, such a sensor is not limited to a temperature sensor, and is a sensor used for detecting various physical quantities such as acceleration and weight. It's okay.

It is a block diagram of the A / D conversion device of one embodiment of the present invention. It is the schematic which shows component arrangement | positioning same as the above. It is a block diagram of the conventional A / D converter. It is the schematic which shows component arrangement | positioning same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Analog signal input part 2 Signal selection part 3 A / D conversion part 4 Arithmetic processing part 5 Memory | storage part 6 Signal amplification part 8 Insulated transmission apparatus CB A / D conversion block TB Data transfer block MB External apparatus

Claims (3)

A signal selection unit that selects and outputs one of the analog signals input to the analog signal input unit to which a plurality of analog signals are input, and creates the digital data by quantizing the analog signal selected by the signal selection unit An A / D conversion block having an A / D conversion unit, and a buffer storage unit for temporarily storing digital data created by the A / D conversion block, and the digital stored in the storage unit A data transfer block that outputs data to an external device, and transmits data between an input end and an output end that are electrically insulated from each other in a transmission path between the A / D conversion block and the data transfer block. An A / D converter with an insulated transmission device to be inserted,
In the A / D conversion block, signal selection processing for controlling the signal selection unit so that a desired analog signal is output from the signal selection unit, and digital data created by the A / D conversion unit are stored in the isolated transmission device An A / D conversion apparatus, comprising: an arithmetic processing unit that executes data output processing to be transmitted to the unit. The A / D conversion block includes a signal amplification unit that amplifies the analog signal selected by the signal selection unit at a predetermined amplification factor and outputs the amplified signal to the A / D conversion unit.
2. The A / D according to claim 1, wherein the arithmetic processing unit executes an amplification factor setting process for setting an amplification factor in the signal amplification unit in accordance with the type of the analog signal selected by the signal selection unit. Conversion device.   The arithmetic processing unit converts the digital data created by the A / D conversion unit according to the type of the analog signal selected by the signal selection unit into digital data suitable for processing by the external device. The A / D conversion apparatus according to claim 1, wherein:

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