Signal output device and method for producing the same

Abstract

To prevent a deterioration in accuracy of an output signal depending on a type of a power source connected to a signal output device.SOLUTION: A signal output device 10 can be connected with a plurality of types of power sources S, and the device which is configured to operate by electric power from the power source connected thereto, of the plurality of types of power sources S. A signal conversion circuit 30 of the signal output device 10 is configured to derive a voltage conversion value P1 on the basis of an input signal Vin from a sensor element 20, convert the derived voltage conversion value P1 into an output signal Vout, and output the converted output signal Vout. Further, a power source detection circuit 50 of the signal output device 10 detects a type of the power source S connected to the signal output device 10, of the plurality of types of power sources. The signal conversion circuit 30 corrects the voltage conversion value P1 in accordance with the type of the power source S identified by the power source detection circuit 50 and then converts the voltage conversion value to the output signal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a signal output device that outputs an output signal such as a voltage signal of 0 to 10 V, and a method for producing the same. [Background technology]

[0002] In a signal output device such as a vacuum gauge, the voltage value (output voltage) of the output signal may change depending on the external environment, so when the output signal is generated, a correction may be made depending on the external environment (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-258088 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, there are signal output devices that are configured to be connectable to multiple types of power sources. In such signal output devices, the voltage value of the output signal may change depending on the power source actually used, which may result in a decrease in the accuracy of the output signal. This is not taken into consideration in Patent Document 1.

[0005] An object of the present invention is to reduce a decrease in accuracy of an output signal caused by the type of power supply connected to a signal output device. [Means for solving the problem]

[0006] In order to solve the above problems, the signal output device of the present invention is a signal output device to which multiple types of power sources can be connected and which operates using power from a connected power source among the multiple types of power sources, and is equipped with a signal conversion circuit that derives a numerical value based on an input signal, converts the derived numerical value into an output signal, and outputs the converted output signal, and a power supply detection circuit that detects the type of power supply connected to the signal output device among the multiple types of power sources, and the signal conversion circuit corrects the numerical value in accordance with the type of power supply identified by the power supply detection circuit before converting it into the output signal.

[0007] As an example, the signal output device may further include a power supply circuit to which one of the multiple types of power supplies is connected, the power supply circuit having a location where a different voltage is generated depending on the type of power supply connected, the power supply detection circuit detecting the type by measuring the voltage at the location, and the signal conversion circuit correcting the numerical value based on the voltage detected by the power supply detection circuit and a preset correction coefficient.

[0008] As an example, the signal conversion circuit may correct the numerical value by converting it into another numerical value using the correction coefficient corresponding to the type of power supply identified by the power supply detection circuit, and then convert it into the output signal.

[0009] As an example, the multiple types of power sources may include a single power source and a dual power source.

[0010] As an example, the input signal may be indicative of a physical quantity sensed by a sensor element.

[0011] A method for producing a signal output device according to the present invention includes a first step of assembling the signal output device, and a second step of setting a correction coefficient to be used when correcting the numerical value in the signal conversion circuit provided in the signal output device after assembly. Effect of the Invention

[0012] According to the present invention, it is possible to reduce the deterioration of accuracy of an output signal caused by the type of power supply connected to a signal output device. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a configuration diagram of a signal output device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a circuit diagram of a portion of the power supply circuit of FIG. 1 and a single power supply. [Diagram 3] FIG. 3 is a circuit diagram of a portion of the power supply circuit of FIG. 1 and both power supplies. [Figure 4] FIG. 4 is a circuit diagram of the output circuit of FIG. [Diagram 5] FIG. 5 is a flow chart of the production of the signal output device. [Figure 6] FIG. 6 is a flowchart of the process of setting the correction coefficient VCOMK. [Figure 7] FIG. 7 is a flowchart of the process performed by the arithmetic circuit. [Figure 8] FIG. 8 is a graph for explaining that the output voltage Vout varies depending on the type of power supply, and that this variation can be reduced by correction. [Figure 9] FIG. 9 is a flowchart of a process for setting the correction coefficients aij and bij according to the second embodiment. [Figure 10] FIG. 10 is a flowchart of the process performed by the arithmetic circuit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0015] (First embodiment) The signal output device 10 according to the present embodiment shown in Fig. 1 is configured as a capacitance-type diaphragm vacuum gauge. The signal output device 10 includes a sensor element 20, a signal conversion circuit 30, a power supply circuit 40, a power supply detection circuit 50, and a temperature measurement circuit 60.

[0016] The sensor element 20 detects a pressure value (physical quantity) of an object to be measured by converting the pressure value into an analog electrical signal indicating the pressure value. The converted analog electrical signal is input from the sensor element 20 to the signal conversion circuit 30 as an input signal Vin.

[0017] The signal conversion circuit 30 converts an input signal Vin into an output signal Vout via a voltage conversion value described later and outputs the output signal Vout. The signal conversion circuit 30 includes a signal processing circuit 31, an AD converter 32, an arithmetic circuit 33, a DA converter 34, and an output circuit 35.

[0018] The signal processing circuit 31 includes a signal amplification circuit, a filter circuit, etc., and performs processing such as amplification and noise removal on the analog electrical signal from the sensor element 20 .

[0019] The AD converter 32 converts the analog electrical signal output from the signal processing circuit 31 into digital data and outputs the digital data. The digital data indicates the pressure value of the object to be measured.

[0020] The arithmetic circuit 33 is composed of a microcomputer or the like, and converts the value of the digital data from the AD converter 32 into a voltage value of 0 to 10 V. The converted voltage value is also called a voltage converted value. The arithmetic circuit 33 calculates a DA count value based on the voltage converted value. The DA count value is a numerical value obtained by converting the voltage converted value or the pressure value of the object to be measured into a format that can be digital-to-analog converted by the DA converter 34. The arithmetic circuit 33 outputs the calculated DA count value to the DA converter 34.

[0021] The DA converter 34 generates a voltage signal indicating an analog voltage value based on the DA count value. This converts the voltage converted value into a voltage signal. The converted voltage signal is output to the output circuit 35.

[0022] The output circuit 35 amplifies the voltage signal from the DA converter 34, and generates and outputs an output signal Vout indicating the pressure value of the object to be measured indicated by the voltage signal, by a voltage value of 0 to 10 V. The circuit configuration of the output circuit 35 will be described in detail later.

[0023] Either a single power supply S1 or a dual power supply S2 is connected to the power supply circuit 40. The single power supply S1 and the dual power supplies S2 are collectively referred to as power supplies S. The power supply circuit 40 is configured to supply power of the same voltage or current to each of the elements 20-30, 50-60 of the signal output device 10 regardless of which power supply S is connected. Note that the voltage value or current value of the power may differ depending on the supply destination of the power.

[0024] The power supply circuit 40 includes the circuits shown in Fig. 2 and Fig. 3. The power supply circuit 40 includes a first terminal T1, a second terminal T2 connected to a common potential OUTCOM, and a third terminal T3 connected to a ground GND. The terminals T1 to T3 are configured to be connectable to three terminals of a single power supply S1 (Fig. 2) or three terminals of a dual power supply S2 (Fig. 3), respectively. When the single power supply S1 is connected to the power supply circuit 40, the potential difference VOG between the common potential OUTCOM and the ground GND is 0V. When the dual power supplies S2 are connected to the power supply circuit 40, VOG is 15V. In this way, the power supply circuit 40 has a location where a different voltage VOG is generated depending on the type of the power supply S connected.

[0025] The power supply detection circuit 50 detects the type of power supply S connected to the power supply circuit 40 by measuring VOG. Here, the power supply detection circuit 50 detects a single power supply S1 as the type of power supply S by measuring 0V as VOG, and detects a dual power supply S2 as the type of power supply S by measuring 15V as VOG. VOG, which is the detection result, is output to the arithmetic circuit 33.

[0026] The temperature measuring circuit 60 measures the ambient temperature of the sensor element 20, such as the substrate temperature of the substrate on which the above circuits 30 to 50 are mounted, and outputs the measured ambient temperature to the arithmetic circuit 33.

[0027] As described above, the arithmetic circuit 33 of the signal conversion circuit 30 calculates the DA count value based on the voltage conversion value. The arithmetic circuit 33 also has a function of correcting the voltage conversion value, which is the basis of this DA count value, based on the type of power source S detected by the power source detection circuit 50 and the ambient temperature measured by the temperature measurement circuit 60. For the temperature correction based on the ambient temperature, a conventional technique is adopted. The feature of this embodiment is that the voltage conversion value is corrected according to the type of power source S. This point will be explained below. Here, the reason why the voltage conversion value is corrected according to the type of power source S is that the voltage value of the output signal Vout deviates depending on the type of power source S, and this deviation is caused by the circuit configuration of the output circuit 35 that outputs the output signal Vout. Below, the circuit configuration of the output circuit 35 will be explained, and then the correction of the voltage conversion value will be explained.

[0028] As shown in FIG. 4, the output circuit 35 is configured as a negative feedback differential amplifier circuit, and includes input terminals T11 and T12, an output terminal T21, an operational amplifier OP, and resistors R3 to R6. One end of each of resistors R3 and R4 is connected to an inverting input terminal (-) of the operational amplifier OP via a node N1. The other end of the resistor R3 is connected to an output terminal of the operational amplifier OP via a node N3. The output terminal T21 is connected to the node N3. The other end of the resistor R4 is connected to an input terminal T12. One end of each of resistors R5 and R6 is connected to a non-inverting input terminal (+) of the operational amplifier OP via a node N2. The other end of the resistor R5 is connected to an input terminal T11. The other end of the resistor R6 is connected to a reference potential OUTCOM.

[0029] A voltage signal is input to the input terminal T11 from the DA converter 34. A fixed voltage is input to the input terminal T12 from the power supply circuit 40. The voltage signal input to the input terminal T11 is Va with respect to the ground GND. The fixed voltage input to the input terminal T12 is also Vb with respect to the ground GND. When the common potential OUTCOM is used as the reference, these voltages are Va-VOG and Vb-VOG, respectively, because the potential difference between the common potential OUTCOM and the ground GND is VOG (see Figures 2 and 3).

[0030] If the resistance values ​​of the resistors R3 to R6 are r3 to r6, the potential Vc of the node N2 is calculated by the following formula (A).

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[0031] The output signal Vout, which is amplified by the output circuit 35 and output from the output terminal T21, is calculated by the following formula (B). The output signal Vout is a voltage signal, and the voltage value of the output signal Vout is also referred to as Vout or output voltage Vout as appropriate.

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[0032] When the above formula (A) is substituted for "Vc" in the above formula (B) and transformed, the output voltage Vout is expressed by the following formula (C).

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[0033] As is clear from the form of the above formula (C), the value of the first term of formula (C) does not include a value that varies depending on the type of power supply S, and is therefore constant regardless of the type of power supply S. On the other hand, the value of the second term includes the voltage VOG, whose value varies depending on the type of power supply S, and therefore varies depending on the type of power supply S. Here, in the output circuit 35, resistors R3 to R6 are selected such that r4=r5 and r3=r6, so the above second term is ideally 0, and the type of power supply S does not matter. However, in reality, even resistors of the same type have variations in resistance value (relative error), so the above second term does not become 0. Here, when the single power supply S1 is used, VOG becomes 0, so the second term becomes 0 regardless of the variations in resistance value. However, when the dual power supplies S2 are used, VOG becomes 15V, so the second term does not become 0. In other words, when the dual power supplies S2 are used, Vout deviates from when the single power supply S1 is used. In this embodiment, a correction is made to cancel the value of this second term, and the deviation of the output voltage Vout is suppressed. This correction will be described below.

[0034] When the single power supply S1 is connected, Vout and VOG are respectively Vout(single) and VOG(single), and when the dual power supplies S2 are connected, Vout and VOG are respectively Vout(both) and VOG(both). In addition, the part in parentheses of the second term of the above formula (C) is VCOMK as shown in the following formula (D).

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[0035] Here, if we take the difference between Vout (double) and Vout (single), we get the following formula (E). The difference between Vout (double) and Vout (single) indicates the amount of deviation in the output voltage Vout between the dual power supply S2 and the single power supply S1. Rearranging the formula (E) below gives the following formula (F). Vout(both)-Vout(single)=VCOMK*(VOG(both)-VOG(single)) (E) VCOMK=(Vout(both)-Vout(single)) / (VOG(both)-VOG(single)) (F)

[0036] Here, when dual power supplies S2 are used, the value of the output voltage Vout from the output circuit 35 will deviate by 0.5% when 10V is the full scale (100%) compared to when the single power supply S1 is used. If the pressure of the object to be measured is the same, the value of the digital data from the AD converter 32 that is input to the arithmetic circuit 33 will be the same for the single power supply S1 and dual power supplies S2, and Vout should also be the same. However, since Vout deviates as described above, this amount is corrected by the arithmetic circuit 33.

[0037] The arithmetic circuit 33 converts the digital data into a voltage equivalent value as described above, and also multiplies VCOMK by VOG to derive a correction value, and performs correction by subtracting the correction value from the voltage equivalent value. VCOMK is set in the arithmetic circuit 33 as a correction coefficient (details will be described later). VOG is measured by the power supply detection circuit 50. As described above, the deviation of Vout when both power supplies S2 are used is set to 0.5% FS, so 0.05V is calculated as the correction value here. Therefore, the voltage equivalent value after correction is 5V-0.05V=4.95V. The arithmetic circuit 33 calculates a DA count value from this voltage equivalent value, thereby obtaining an output voltage Vout=5V with the deviation corrected.

[0038] The correction coefficient VCOMK is set during the production of the signal output device 10 shown in Fig. 5. As shown in Fig. 5, in the production of the signal output device 10, the signal output device 10 is assembled (step S11), and then the assembled signal output device 10 is initialized (step S12). The initial setting includes characterization, which derives parameters specific to the signal output device 10 and sets the derived parameters in the signal output device 10. The parameters derived and set include the correction coefficient VCOMK. The parameters also include the correction coefficient a for the temperature correction described above. ij Also included is the correction coefficient a ij are coefficients of a polynomial, and since the conventional ones are used (for example, they are calculated by an inverse operation using the formula (H) described later), detailed explanations are omitted. By the initial setting, the signal output device 10 becomes operable and is completed as a device.

[0039] The process of setting the correction coefficient VCOMK will be described with reference to Fig. 6. In this process, first, the single power source S1 is connected to the signal output device 10, and the signal output device 10 is started (step S101). After that, an arbitrary DA count value is input to the arithmetic circuit 33 (step S102). After that, the output voltage Vout (single) output from the output circuit 35 is measured, and the voltage VOG (single) of the power supply circuit 40 is measured (step S103).

[0040] After step S103, the power supply S of the signal output device 10 is changed to the two power supplies S2 (step S104). Then, a DA count value that is the same as the DA count value input in step S102 is input to the arithmetic circuit 33 (step S105). Then, the output voltages Vout (both) and voltages VOG (both) are measured (step S106).

[0041] Then, Vout(single), Vout(double), VOG(single), and VOG(double) measured in steps S103 and S106 are substituted into the above formula (F) to calculate the correction coefficient VCOMK (step S107). Then, the derived VCOMK is stored in the memory of the arithmetic circuit 33 (step S108). As a result, VCOMK is set in the arithmetic circuit 33.

[0042] After the initial settings are completed, the arithmetic circuit 33 of the signal output device 10 executes the process shown in Fig. 7 during normal operation of the signal output device 10. The process in Fig. 7 is started when the signal output device 10 is started. At the time of startup, the arithmetic circuit 33 measures and holds the VOG of the power supply circuit 40 using the power supply detection circuit 50.

[0043] In the process of FIG. 7, the arithmetic circuit 33 converts the value of the digital data from the AD converter 32, that is, the value indicating the pressure value of the object to be measured, into a voltage equivalent value P1 of 0 to 10 V (step S201). The arithmetic circuit 33 applies the voltage equivalent value P1 obtained by the conversion to the following formula (G) to correct it and obtain a corrected converted value P2 (step S202). VCOMK is the correction coefficient set above, and VOG is measured and held above. In the case of a single power supply S1, VOG=0, so no correction is performed. P2 = P1 - VCOMK * VOG (G)

[0044] The arithmetic circuit 33 calculates the DA count value based on the corrected converted value P2 obtained in step S202 (step S203), and outputs the calculated DA count value to the DA converter 34 (step S204). If the DA count value is DA, the arithmetic circuit 33 multiplies the DA by a correction coefficient a for temperature correction. ij The DA count value is calculated by the following formula (H) using the ambient temperature BT measured by the temperature measurement circuit 60. ij The corrected converted value P2 also serves to perform temperature correction. In the following formula (H), n and m are arbitrary constants.

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[0045] The DA count value is converted to an analog voltage value by the DA converter 34, amplified to a voltage value of 0 to 10 V by the output circuit 35, and outputted to the outside of the signal output device 10 as an output voltage Vout.

[0046] Steps S201 to S204 are executed every time digital data is supplied from the AD converter 32.

[0047] As described above, in this embodiment, the signal output device 10 is configured to be connectable to a plurality of types of power sources S, and to operate with power from the connected power source among the plurality of types of power sources S. The signal conversion circuit 30 is configured to derive a voltage equivalent value P1 based on an input signal Vin from the sensor element 20, convert the derived voltage equivalent value P1 into an output signal Vout, and output the converted output signal Vout. Furthermore, the power source detection circuit 50 detects the type of the power source S connected to the signal output device 10 among the plurality of types of power sources S, and the signal conversion circuit 30 corrects the voltage equivalent value P1 according to the type of the power source S identified by the power source detection circuit 50 and then converts it into an output signal. Here, when the power source S is a single power source S1, the signal conversion circuit 30 does not correct the voltage equivalent value P1, but converts it into the output signal Vout through conversion into a DA count value by the calculation circuit 33 and conversion into a voltage signal by the DA converter 34. When the power supply S is a dual power supply S2, the signal conversion circuit 30 corrects the voltage conversion value P1, and converts the corrected conversion value P2 obtained by this correction into an output signal Vout via conversion into a DA count value by the calculation circuit 33 and conversion into a voltage signal by the DA converter 34.

[0048] If no correction is made according to the type of power source S, the graph showing the relationship between the output voltage Vout and the input signal Vin (pressure of the object to be measured) when the two power sources S2 are used will deviate from the graph when the single power source S1 is used due to the influence of the above VOG (FIG. 8). In this embodiment, when the two power sources S2 are used, the voltage conversion value P1, which is the numerical value before conversion to the output voltage Vout, can be corrected by the amount of deviation of the output voltage Vout, so that the graph when the two power sources S2 are used can be shifted toward the graph when the single power source S1 is used (FIG. 8), and ideally the two can be made to match. Therefore, according to this embodiment, the decrease in accuracy of the output signal Vout due to the type of power source S connected to the signal output device 10 is reduced.

[0049] As can be seen from the second term of the above formula (C), the deviation of Vout becomes smaller as the difference between r4 and r5 and the difference between r3 and r6 among the resistance values ​​r3 to r6 of the resistors R3 to R6 in FIG. 4 are reduced. Therefore, the deviation can be reduced by using expensive resistors with little variation in resistance as the resistors R3 to R6. However, the correction in this embodiment eliminates the need to reduce the difference between r4 and r5 and the difference between r3 and r6, so there is no need to use the expensive resistors as the resistors R3 to R6. This reduces costs.

[0050] Furthermore, in this embodiment, the power supply circuit 40 is configured so that the power supply S connected to the signal output device 10 is actually connected, and has a location where a different voltage VOG is generated depending on the type of the connected power supply S. The power supply detection circuit 50 detects the type of the power supply S by measuring the voltage VOG at the location, and the signal conversion circuit 30 corrects the voltage conversion value based on the voltage VOG detected by the power supply detection circuit 50 and a preset correction coefficient VCOMK. Therefore, the type of the power supply S can be easily detected by voltage measurement, making it easy to make corrections according to the type of the power supply S.

[0051] In the above, it has been explained that VOG is 0 V when the single power supply S1 is connected, but for example, if a diode for protection against reverse connection of the power supply is provided between the ground GND of the power supply circuit 40 and the third terminal T3 (FIGS. 2 and 3), VOG may become about 0.2 V due to the voltage drop of this diode. Even in such a case, since the above formula (G) is used in the first embodiment, VOG=-0.2 V is substituted into formula (G) to perform accurate correction.

[0052] In the above, the VOG used in the process of Fig. 7 has been described as being measured only at startup, but the VOG may be measured periodically and used during normal operation of the signal output device 10. For example, the VOG may be measured every time step S202 is executed. This allows accurate correction to be performed even if the VOG changes during normal operation.

[0053] Second embodiment In the first embodiment, one correction coefficient is used regardless of the type of power source S, but in this embodiment, a correction coefficient is prepared for each type of power source S. More specifically, in this embodiment, the DA count value is calculated by an equation in which P2 in the above equation (H) is changed to a voltage conversion value P1 (see equations (I) and (J) described later), but the correction coefficient a ij is derived and set for each type of power supply S. In the following, the correction coefficient when using a single power supply S1 is a ij The correction coefficient when using the dual power supply S2 is b ij The following description will focus on the differences from the first embodiment.

[0054] In this embodiment, in step S12 of FIG. 5, the correction coefficient setting process shown in FIG. 9 is executed. In this process, the signal output device 10 is placed in a chamber or the like capable of adjusting the room temperature. In this process, the single power source S1 is connected to the signal output device 10, and the signal output device 10 is started (step S301). After that, the room temperature is set as a first temperature (step S302), a predetermined DA count value is input to the signal output device 10 (step S303), and the output voltage Vout and the ambient temperature BT are measured (step S304). The ambient temperature BT is measured by the temperature measurement circuit 60. At the first temperature, steps S303 and S304 are repeated. More specifically, in the repeated step S303, the DA count value is sequentially increased by a predetermined increment, or a plurality of predetermined DA count values ​​are sequentially applied. Steps S303 and S304 are repeated (step S305) until a preset measurement end condition is met (for example, until the output voltage Vout reaches 10 V or until all of the multiple DA count values ​​have been applied). Thereafter, the room temperature is changed sequentially to a second temperature, a third temperature, ... a predetermined number of times (step S307), and steps S303 to S305 are performed at each temperature (step S306). The DA count value at each temperature is the same as that when the room temperature is the first temperature.

[0055] After step S307, both power sources S2 are connected to the signal output device 10, and it is determined whether steps S302 to S307 have been executed (step S308). If they have not been executed (step S308; No), both power sources S2 are connected to the signal output device 10 (step S309), the signal output device 10 is started, and then steps S302 to S307 are executed.

[0056] When the dual power supply S2 is connected to the signal output device 10 and steps S302 to S307 are executed (step S308; Yes), a correction coefficient a is calculated based on each pair of the DA count value input to the signal output device 10 with the single power supply S1 connected to the signal output device 10 and the output voltage Vout and the ambient temperature BT obtained by the measurement when the DA count value is input. ij (Step S310). ij The variables used to derive are the conventional correction coefficients a ij are the same variables used to derive the correction factor a ij The method of deriving the correction coefficient b is performed by a conventional method. Then, based on each pair of the DA count value input to the signal output device 10 with both power sources S2 connected to the signal output device 10 and the output voltage Vout and the ambient temperature BT obtained by measurement when the DA count value is input, the correction coefficient b ij (Step S311). ij The method of derivation of the correction coefficient a ij is carried out in the same manner as conventional methods.

[0057] Then, the correction factor a ij , b ij is stored in the memory of the arithmetic circuit 33 (step S312). ij , b ij The correction coefficient a is set. ij , b ij are derived when a single power supply S1 and a dual power supply S2 are used, respectively, and reflect the type of power supply S. In particular, the correction coefficient b ij is the correction coefficient b that reflects the second term of the above formula (C) ij It becomes.

[0058] After the initial settings including the processing in Fig. 9 are completed, the arithmetic circuit 33 of the signal output device 10 executes the processing shown in Fig. 10 during normal operation of the signal output device 10. The processing in Fig. 10 is started when the signal output device 10 is started.

[0059] 10, the arithmetic circuit 33 converts the value of the digital data from the AD converter 32, that is, the value indicating the pressure value of the object to be measured, into a voltage equivalent value P1 of 0 to 10 V (step S401). After that, the arithmetic circuit 33 measures the VOG of the power supply circuit 40 by the power supply detection circuit 50, and detects the type of power supply S currently connected to the signal output device 10 (step S402).

[0060] The arithmetic circuit 33 determines whether the type of the current power supply S is the single power supply S1 based on the VOG of the power supply circuit 40 measured in step S202 (step S403). For example, if VOG is within a first range (for example, within a range of -1.0V to 0V set corresponding to VOG=0V or -0.2V when the single power supply S1 is connected), the arithmetic circuit 33 determines that the current type is the single power supply S1. For example, if VOG is within a second range (for example, within a range of 14V to 16V set corresponding to VOG=15V when the dual power supplies S2 are connected), the arithmetic circuit 33 determines that the current type is the dual power supply S2.

[0061] If the type of the power source S this time is the single power source S1 (step S403; Yes), the calculation circuit 33 calculates the voltage conversion value P1 obtained by the above conversion, the correction coefficient a for the single power source S1 set in the initial setting, ij , and calculates the DA count value based on the following formula (I) (step S404). In the following formula (I), DA is the DA count value, BT is the ambient temperature measured by the temperature measurement circuit 60, and n and m are arbitrary constants. In step S404, the arithmetic circuit 33 uses the ambient temperature BT measured by the temperature measurement circuit 60.

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[0062] If the type of the power source S this time is the dual power source S2 (step S403; No), the calculation circuit 33 calculates the voltage conversion value P1 obtained by the above conversion, the correction coefficient b ij , and calculates the DA count value based on the following formula (J) (step S405). The explanations of DA, BT, n, and m in the following formula (J) are the same as those in the above formula (I).

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[0063] After step S404 or S405, the arithmetic circuit 33 outputs the calculated DA count value to the DA converter 34 (step S406). The output DA count value is converted to an analog voltage value by the DA converter 34, amplified to a voltage value of 0 to 10 V by the output circuit 35, and output to the outside of the signal output device 10 as the output voltage Vout.

[0064] Steps S401 to S406 are executed every time digital data is supplied from the AD converter 32.

[0065] As described above, in this embodiment, the signal conversion circuit 30 corrects the voltage conversion value P1 in accordance with the type of the power supply S identified by the power supply detection circuit 50, and then converts it into an output signal. Here, when the power supply S is a single power supply S1, the signal conversion circuit 30 converts the voltage conversion value P1 into an output signal by using a correction coefficient a ij Then, the signal conversion circuit 30 converts the voltage conversion value P1 into a voltage signal by the DA converter 34, and converts it into the output signal Vout. ij Then, the DA count value is corrected and converted to a DA count value using the correction coefficient b, and then converted to a voltage signal by the DA converter 34, and then converted to the output signal Vout. ijThus, when the DA count value is calculated based on the voltage conversion value P1, the voltage conversion value P1 is corrected by the amount of deviation of the output voltage Vout. This makes it possible to make the output voltage Vout of the single power supply S1 and the dual power supplies S2 closer to each other, and ideally to match each other. Therefore, according to this embodiment, the decrease in accuracy of the output signal Vout caused by the type of the power supply S connected to the signal output device 10 is reduced. Furthermore, according to this embodiment, as in the first embodiment, it is not necessary to use expensive resistors, and the cost of the signal output device 10 can be reduced.

[0066] Furthermore, in this embodiment, the signal conversion circuit 30 converts the voltage conversion value P1 into a correction coefficient a corresponding to the type of the power source S identified by the power source detection circuit 50. ij or b ij The correction coefficients used for conversion to DA count values ​​are then used to correct the signal before being converted to the output signal Vout. Therefore, by providing multiple types of correction coefficients for use in conversion to DA count values ​​according to the type of power source S, it is possible to reduce the decrease in accuracy of the output signal Vout.

[0067] (Modification) The present invention is applicable to a general signal output device that can be connected to multiple types of power sources and operates with power from a connected power source among the multiple types of power sources. The signal output device may include, for example, a signal conversion circuit that derives a numerical value based on an input signal, converts the derived numerical value into an output signal, and outputs the converted output signal, and a power source detection circuit that detects the type of power source connected to the signal output device among the multiple types of power sources. The signal conversion circuit may convert the numerical value into an output signal after correcting it according to the type of power source identified by the power source detection circuit. The specific configurations of these are not limited to the above-mentioned embodiment. For example, in the above-mentioned embodiment, the sensor element 20 may be changed to an element that detects a physical quantity other than the pressure value. The arithmetic circuit 33 may be configured by an FPGA or an ASIC. The power sources that can be connected to the signal output device 10 are not limited to the single power source S1 and the dual power sources S2 described above. The specific value of VOG when the power source is connected is not limited to 0V or 15V, and may be other values ​​(in this case, the above-mentioned first range or second range is also changed). VOG may be any voltage value that varies depending on the type of power supply.

[0068] A production method for a signal output device may include, for example, a first step of assembling the signal output device, and a second step of setting a correction coefficient to be used when correcting the numerical value in the signal conversion circuit provided in the signal output device after assembly, and the specific form thereof is arbitrary.

[0069] (Scope of the present invention) Although the present invention has been described above with reference to the embodiments and modifications, the present invention is not limited to the above embodiments and modifications. For example, the present invention includes various modifications to the above embodiments and modifications that can be understood by a person skilled in the art within the scope of the technical concept of the present invention. The configurations listed in the above embodiments and modifications can be appropriately combined within a range without contradiction. Also, the omission of each configuration is optional. [Explanation of symbols]

[0070] 10...signal output device, 20...sensor element, 30...signal conversion circuit, 31...signal processing circuit, 32...AD converter, 33...arithmetic circuit, 34...DA converter, 35...output circuit, 40...power supply circuit, 50...power supply detection circuit, 60...temperature measurement circuit, N1 to N3...nodes, S...power supply, S1...single power supply, S2...dual power supplies, T1 to T3...first to third terminals, T11...input terminal, T12...input terminal, T21...output terminal, Vin...input signal, Vout...output signal (output voltage).

Claims

1. A signal output device to which a plurality of types of power sources can be connected and which operates using power from a connected power source among the plurality of types of power sources, a signal conversion circuit that derives a numerical value based on an input signal, converts the derived numerical value into the output signal, and outputs the converted output signal; a power supply detection circuit that detects a type of a power supply connected to the signal output device, among the plurality of types of power supplies; the signal conversion circuit corrects the numerical value in accordance with the type of the power supply identified by the power supply detection circuit and then converts it into the output signal. Signal output device.

2. a power supply circuit to which the power supply among the plurality of types of power supplies is connected, the power supply circuit has a portion where a different voltage is generated depending on the type of the power supply connected thereto; The power supply detection circuit detects the type by measuring a voltage at the location; the signal conversion circuit corrects the numerical value based on the voltage detected by the power supply detection circuit and a preset correction coefficient.

2. The signal output device according to claim 1.

3. the signal conversion circuit corrects the numerical value by converting it into another numerical value using the correction coefficient corresponding to the type of the power supply identified by the power supply detection circuit, and then converts it into the output signal.

2. The signal output device according to claim 1.

4. The multiple types of power sources include a single power source and a dual power source.

2. The signal output device according to claim 1.

5. The input signal indicates a physical quantity detected by a sensor element.

2. The signal output device according to claim 1.

6. A method for producing the signal output device according to any one of claims 1 to 5, comprising the steps of: a first step of assembling the signal output device; a second step of setting a correction coefficient used for correcting the numerical value in the signal conversion circuit included in the signal output device after assembly; A method for producing a signal output device.

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