JP4782721B2 - measuring device - Google Patents

Description

  The present invention relates to a measuring apparatus configured to be able to repeatedly execute measurement of a predetermined physical quantity based on measurement target signals input from a plurality of channels while switching channels.

As this type of measuring device, an input device disclosed in Japanese Patent No. 3178944 is known. This input device includes an input switching device, a filter circuit, an amplifier, an A-D converter, and a processing means, and is configured to be able to measure measurement input signals input through a plurality of channels. In this case, this input device switches the zero input switch of the input switch and supplies the zero input signal to the filter circuit to identify the drift amount (offset value) caused by the characteristics of the amplifier and measure the drift amount. The effect of drift is eliminated by subtracting from the value.
Japanese Patent No. 3178944 (2nd page, Fig. 1)

  However, the above input device has the following problems. That is, in this input apparatus, in order to eliminate the influence of the drift, the zero input signal is supplied by switching the zero input switch to specify the drift. In this case, in this type of input device capable of inputting measurement input signals through a plurality of channels, the amplification factor differs for each type of measurement input signal, that is, for each channel, so that it is necessary to specify the drift amount for each channel. Therefore, in this type of input device including the above input device, it is necessary to specify the drift amount by switching the zero input switch every time the channel is switched, that is, every time the amplification factor is changed. There is a problem of doing. In this case, for example, when an automatic monitoring system incorporating this input device is used to continuously measure physical quantities such as voltages at a plurality of measurement points in the monitoring target device while switching the switches as described above. In some cases, the automatic monitoring function may be hindered due to a decrease in processing speed.

  The present invention has been made in view of such problems, and a main object of the present invention is to provide a measuring apparatus capable of improving the processing speed when performing continuous measurement.

  In order to achieve the above object, the measuring apparatus according to claim 1 includes a switching unit that switches and outputs a plurality of measurement target signals respectively input from a plurality of channels by channel switching, and the measurement target that is output from the switching unit. A signal processing unit that executes predetermined signal processing including amplification processing at a gain corresponding to a channel on the signal, and a processing signal that is signal-processed by the signal processing unit while causing the switching unit to perform the channel switching A control unit that calculates a predetermined physical quantity based on the signal, specifies an offset value due to the electrical characteristics of the signal processing unit for each channel, and adjusts the calculated physical quantity based on the offset value; A measuring device configured to repeatedly execute the measurement of the physical quantity, wherein the control unit is configured to satisfy a predetermined condition. The measurement of the physical quantity based on the processing signals for all the channels is performed once, and the offset value is newly specified only for a part of the channels during one round measurement. In addition, the physical quantity is measured in the first mode in which the offset values for all the channels are newly specified while the round measurement is performed a plurality of times. In this case, all the channels that execute the measurement of the physical quantity based on each measurement target signal once in one round measurement mean all the channels that are measurement targets among the channels of the measurement apparatus. Therefore, for example, when 8 channels are provided and 6 of the 8 channels are to be measured, all channels mean all 6 channels to be measured.

  The measuring apparatus according to claim 2 is the measuring apparatus according to claim 1, wherein the control unit sets the offset value only for one channel during the round measurement once in the first mode. Newly identify.

  The measuring device according to claim 3 is the measuring device according to claim 1 or 2, further comprising a temperature detecting unit that detects the temperature of at least one of the inside and the surrounding of the measuring device, and the control unit includes the temperature When the rate of change of the temperature detected by the detection unit exceeds a first predetermined value, the offset value for all the channels is newly specified each time the round measurement is performed once in the second mode. The physical quantity is measured, and the physical quantity is measured in the first mode on the assumption that the predetermined condition is satisfied when the rate of change of the temperature is equal to or less than the first predetermined value.

  Furthermore, the measuring device according to claim 4 is the measuring device according to claim 3, wherein the control unit is configured to set the offset value when the rate of change of the temperature is equal to or smaller than a second predetermined value smaller than the first predetermined value. The measurement of the physical quantity is executed in the third mode in which the new identification is omitted.

  According to the measuring apparatus of claim 1, an offset value is newly specified only for a part of all channels during one round measurement, and all the round measurements are performed during one round measurement. By measuring a physical quantity (for example, a voltage value) in the first mode in which an offset value for a channel is newly specified, new specification of an offset value for a channel other than a new target channel can be omitted. . For this reason, as a result of being able to sufficiently shorten the processing time required for one round measurement, it is possible to sufficiently improve the processing speed when performing continuous measurement. Therefore, according to this measurement apparatus, for example, even when the physical quantity (voltage value as an example) at a plurality of measurement points in the measurement object is continuously measured while performing channel switching, the measurement object is automatically monitored. It is possible to reliably prevent a situation in which the automatic monitoring function is hindered due to a decrease in processing speed.

  In addition, according to the measuring apparatus of claim 2, by newly specifying an offset value for only one channel during one round measurement, two or more (all all) during one round measurement are performed. Compared to a configuration that newly specifies an offset value for less than the number of channels), the processing time required for one-round measurement can be further shortened, so that the processing speed for continuous measurement is further improved. Can do.

  According to the measuring device of claim 3, when the rate of change of the temperature detected by the temperature detector exceeds the first predetermined value, the physical quantity (voltage value as an example) is measured in the second mode, When the rate of change in temperature is less than or equal to the first predetermined value, the physical rate (voltage value as an example) is measured in the first mode, so that the rate of change in temperature is large, and the offset value may change greatly accordingly. In such a case, offset values for all channels are newly specified every time one round measurement is performed. Therefore, even if the offset value changes greatly, the offset adjustment process can be performed sufficiently accurately.

  Further, according to the measurement device of claim 4, when the rate of change in temperature is equal to or lower than the second predetermined value smaller than the first predetermined value, the physical quantity (voltage value as an example) is measured in the third mode. When the rate of change in temperature is sufficiently small and the change in offset value is also sufficiently small, new identification of offset values for all channels is omitted, so that the processing time can be further shortened, resulting in continuous The processing speed when performing measurement can be further improved.

  Hereinafter, the best mode of a measuring apparatus according to the present invention will be described with reference to the drawings.

  First, the configuration of the measuring apparatus 1 will be described with reference to the drawings. A measuring apparatus 1 shown in FIG. 1 is an example of a measuring apparatus according to the present invention, and includes a switching unit 2, a signal processing unit 3, a temperature detection unit 4, a control unit 5, a storage unit 6, and a data transmission unit 7. It is configured. The switching unit 2 inputs a plurality of (for example, eight) measurement target signals Sm1 to Sm8 (hereinafter also referred to as “measurement target signal Sm” when not distinguished), and input terminal pairs 21a to 21h (hereinafter referred to as “not distinguished”). An input unit 11 of eight channels CH1 to CH8 (hereinafter also referred to as “channel CH” when not distinguished) and one of the measurement target signals Sm of each channel CH having “input terminal pair 21”). A switching circuit 12 having switches 22a to 22p (hereinafter also referred to as "switch 22" when not distinguished) for switching and outputting, and an offset adjusting switch 13 for connecting the input unit of the signal processing unit 3 to the ground potential And a plurality of measurement target signals Sm respectively input from a plurality (eight in this example) of channels CH. Yan'neru switching (i.e., switching of the switch 22) for switching outputs one by.

  The signal processing unit 3 includes a filter circuit 31 that filters the measurement target signal Sm output from the switching unit 2, an amplifier 32 that amplifies the filtered measurement target signal Sm with a predetermined amplification factor, and an amplified measurement. It comprises an A / D converter 33 that performs analog-digital conversion on the target signal Sm and outputs measurement data Dm (processed signal in the present invention). In this case, the amplifier 32 is configured by connecting amplifier circuits such as operational amplifiers in multiple stages, and each amplifier circuit performs an amplification operation with each gain according to the gain control signal Sg output from the control unit 5. Thus, the measurement target signal Sm is amplified by the total gain (amplification factor corresponding to the channel in the present invention) for each channel CH defined in advance as the entire amplifier 32 (execution of amplification processing in the present invention). As the amplifier 32, an amplifier circuit can be configured in one stage. Further, a plurality of amplifiers 32 may be provided, and one of the plurality of amplifiers 32 may be selectively switched according to the channel CH and operated. Further, the amplifier 32 can be configured by combining an amplifier circuit and an attenuator using a passive element such as a resistor. Furthermore, the amplifier 32 can be configured by an attenuator using an amplifier circuit (active element) to define a gain of 1 or more or 1 or less. In addition, each process performed by the filter circuit 31, the amplifier 32, and the A / D converter 33 corresponds to a predetermined signal process in the present invention. The temperature detector 4 detects the temperature inside the measuring device 1 (an example of at least one of the temperature inside and around the measuring device in the present invention) and outputs a detection signal St. In this case, the temperature detector 4 can be installed outside the measuring device 1 to measure the temperature around the measuring device.

  The control unit 5 executes a measurement process 50 to be described later, based on the measurement data Dm output from the signal processing unit 3, a predetermined physical quantity (as an example, the voltage value Vm) for the measurement target signal Sm of each channel CH. ) Is repeated. In this case, the control unit 5 outputs the control signal Sc and controls the switching circuit 12 of the switching unit 2, whereby one measurement target signal Sm among the measurement target signals Sm of each channel CH is set in a predetermined order ( For example, the measurement target signal Sm processed by the signal processing unit 3 (in other words, the measurement data Dm processed by the measurement target signal Sm and output by the signal processing unit 3) is output while being switched in order of channel CH number). The voltage value V of the measurement target signal Sm is measured based on the above. The measurement of the voltage value V based on the measurement target signal Sm of all the channels CH to be measured among the channels CH1 to CH8 while switching the channels once is also referred to as “one-round measurement”. Further, the control unit 5 outputs the gain control signal Sg, and sets the amplification factor of the amplifier 32 to a predetermined amplification factor for each channel CH. Further, the control unit 5 offsets the above-described physical quantity (in this example, the voltage value V) caused by the electrical characteristics of the filter circuit 31, the amplifier 32, and the A / D conversion unit 33 configuring the signal processing unit 3. An offset adjustment process is performed in which the difference between the measurement target signal Sm and the actual physical quantity) is specified, and the measured physical quantity is adjusted with the specified offset value. In this case, the control unit 5 stores the offset data Do for the specified offset value in the storage unit 6.

  Furthermore, the control unit 5 measures the temperature change rate (hereinafter also referred to as “temperature change rate Tr”) in the measuring device 1 based on the detection signal St output from the temperature detection unit 4, and the temperature change Depending on the rate Tr, the measurement process 50 is executed in one of the measurement modes of a first mode, a second mode, and a third mode, which will be described later. In this case, when the temperature change rate Tr becomes equal to or lower than the first reference value (first predetermined value in the present invention: 0.2 ° C./sec as an example) (the predetermined condition in the present invention). When the temperature change rate Tr exceeds the first reference value, the measurement process 50 is executed in the second mode. Further, the control unit 5 executes the measurement process 50 in the third mode when the temperature change rate Tr becomes equal to or less than the second reference value (second predetermined value in the present invention: 0.1 ° C./sec as an example). To do.

  The storage unit 6 stores the amplification factor of the amplifier 32 defined in advance for each channel CH. Further, the storage unit 6 stores the offset data Do according to the control of the control unit 5. The data transmission unit 7 transmits the physical quantity data measured by the control unit 5 (in this example, the voltage data Dv for the voltage value V) to an external device (not shown).

  Next, operation | movement of the measuring apparatus 1 is demonstrated with reference to drawings. In this case, the measurement apparatus 1 inputs eight measurement target signals Sm1 to Sm8 via each input terminal pair 21 of the input unit 11 in the switching unit 2, and calculates the voltage value V for each measurement target signal Sm1 to Sm8. Shall be measured.

  In the measurement apparatus 1, the control unit 5 starts the measurement process 50 shown in FIG. 3 in accordance with a measurement start operation by an operation unit (not shown) or a measurement start instruction signal from an external device. In this measurement process 50, the control unit 5 reads the amplification factor of the amplifier 32 that is defined in advance for each channel CH from the storage unit 6 (step 51). Next, the control unit 5 specifies an offset value for each channel CH (step 52). Specifically, the control unit 5 connects the input unit of the signal processing unit 3 (filter circuit 31) to the ground potential by outputting the control signal Sc and shifting the offset adjustment switch 13 to the ON state.

  Subsequently, the control unit 5 outputs the gain control signal Sg and sets the amplification factor of the amplifier 32 to the amplification factor corresponding to the channel CH1. At this time, the A / D conversion unit 33 outputs measurement data Dm for an offset value resulting from the electrical characteristics of the signal processing unit 3 at the amplification factor. Next, the control unit 5 specifies an offset value based on the measurement data Dm and causes the storage unit 6 to store the offset data Do (offset data Do for the channel CH1). Subsequently, the control unit 5 outputs the gain control signal Sg, sets the amplification factor of the amplifier 32 to the amplification factor corresponding to the channel CH2, and executes the same process as described above, thereby performing the process for the channel CH2. Are stored in the storage unit 6. Next, the control unit 5 stores the offset data Do for the channels CH3 to CH8 in the storage unit 6 in the same manner.

  Subsequently, the control unit 5 performs measurement of the voltage value V for the measurement target signal Sm of each channel CH1 to CH8 and offset adjustment processing for the voltage value V (step 53). Specifically, the control unit 5 outputs the measurement target signal Sm1 of the channel CH1 by outputting the control signal Sc and shifting the switches 22a and 22b of the switching circuit 12 in the switching unit 2 to the ON state. Next, the control unit 5 outputs the gain control signal Sg and sets the amplification factor of the amplifier 32 to the amplification factor corresponding to the channel CH1. At this time, the filter circuit 31 filters the measurement target signal Sm1, and the amplifier 32 amplifies the measurement target signal Sm1 with the set amplification factor. Subsequently, the A / D converter 33 performs analog-digital conversion on the amplified measurement target signal Sm and outputs measurement data Dm.

  Next, the control unit 5 measures the voltage value V for the measurement target signal Sm1 based on the measurement data Dm, and also compares the voltage value V based on the offset data Do for the channel CH1 stored in the storage unit 6. The offset adjustment process is executed, and the voltage data Dv for the voltage value V after the offset adjustment process is output to the data transmission unit 7. Subsequently, the control unit 5 controls the data transmission unit 7 to transmit the voltage data Dv to the external device. Next, the control unit 5 performs similar processing to output voltage data Dv for the measurement target signals Sm2 to Sm8 of the channels CH2 to CH8, and controls the data transmission unit 7 to output the voltage data Dv. Transmit (step 54).

  Subsequently, the control unit 5 measures the temperature change rate Tr inside the measurement apparatus 1 based on the detection signal St output from the temperature detection unit 4 at the time when the round measurement is performed once (step 55). . Next, the control unit 5 compares the measured temperature change rate Tr with the first reference value (0.2 ° C./sec) and the second reference value (0.1 ° C./sec) to determine the measurement mode ( Step 56). At this time, for example, when the temperature change rate Tr exceeds the first reference value (0.2 ° C./sec), that is, the temperature change is large, and the offset value may change greatly accordingly. Sometimes, the control unit 5 determines the measurement mode as the second mode.

  In the second mode, the control unit 5 newly sets offset values for all the channels CH to be measured (channels CH1 to CH8 in this example) in step 52 described above every time one round measurement is performed. Identify and update, then perform steps 53-56. Therefore, in the second mode, it is possible to accurately perform the offset adjustment process even if the offset value changes greatly. Thereafter, when the temperature change rate Tr exceeds the first reference value, the control unit 5 repeatedly executes Step 52 to Step 56 in the second mode.

  Next, for example, when the temperature change rate Tr measured in step 55 is equal to or less than the first reference value, that is, when the temperature change is small and the change in the offset value is also small, the control unit 5 sets the measurement mode to the first mode. Determine (change) the mode. In the first mode, the control unit 5 newly specifies and updates an offset value only for a part of all the channel CHs (for example, one channel CH) in step 52, 53 to 56 are executed. That is, in the first mode, the control unit 5 sets the offset value only for some of the channels CH1 to CH8 during one round measurement (for one execution of the round measurement). Newly identify and update.

  In this case, in step 53, the control unit 5 performs an offset adjustment process on the newly specified (updated) target channel CH based on the newly specified latest offset value, and for other channel CHs, The offset adjustment process is executed using the offset value specified immediately before. Further, in this first mode, as shown in FIG. 3, the control unit 5 changes a new specific target channel CH every time a round measurement is performed once, and performs a round measurement a plurality of times (in this example, 8 times). Times), the offset values for all the channels CH1 to CH8 are newly specified and updated. Thereafter, when the temperature change rate Tr is equal to or lower than the first reference value, the control unit 5 repeatedly executes Step 52 to Step 56 in the first mode. In this case, in the first mode, since one round of measurement is performed once, new identification (update) of offset values for some channels CH (seven channels CH in this example) is omitted. Can be shortened sufficiently.

  Next, for example, when the temperature change rate Tr measured in step 55 becomes equal to or lower than the second reference value (0.1 ° C./sec), that is, the temperature change is sufficiently small and the change in the offset value is also sufficiently small. Sometimes, the control unit 5 determines (changes) the measurement mode to the third mode. In the third mode, the control unit 5 does not execute Step 52, that is, omits changing the offset value, and executes Steps 53 to 56 described above. In this case, the control unit 5 performs an offset adjustment process in step 53 using the offset value specified immediately before. In the third mode, since the new identification (update) of the offset values for all the channels CH1 to CH8 is omitted, the processing time can be further shortened.

  Thereafter, the control unit 5 repeatedly executes the above steps 52 to 56 and repeatedly executes the measurement process in one of the processing modes of the first mode, the second mode, and the third mode.

  As described above, according to the measurement apparatus 1, when the temperature change rate Tr is equal to or less than the first reference value, the offset value is set only for some of the channels CH during one round of measurement. By measuring the voltage value V in the first mode in which the offset values for all the channels CH1 to CH8 are newly specified and updated while performing one round measurement a plurality of times, the temperature is measured. When the change rate Tr is small and the change in the offset value is also small, new specification (update) of the offset value for the channel CH excluding the channel CH to be newly specified (updated) can be omitted. For this reason, as a result of being able to sufficiently shorten the processing time required for one round measurement, it is possible to sufficiently improve the processing speed when performing continuous measurement. Therefore, according to this measuring apparatus 1, for example, even when the voltage values V at a plurality of measurement points in the measurement object are continuously measured while performing channel switching, the measurement object is automatically monitored. It is possible to reliably prevent a situation in which the automatic monitoring function is hindered due to the decrease.

  Further, according to this measuring apparatus 1, by newly specifying an offset value for only one channel CH during one round measurement, two or more (all channel CHs) during one round measurement are performed. The processing time required for one-round measurement can be further shortened compared to a configuration in which offset values for channel CHs newly specified) are newly specified, so that the processing speed when performing continuous measurement is further improved. Can do.

  Furthermore, according to the measuring apparatus 1, the voltage value V is measured in the second mode when the temperature change rate Tr exceeds the first reference value, and the first mode when the temperature change rate Tr is less than or equal to the first reference value. When the temperature change rate Tr is large by measuring the voltage value V and there is a possibility that the offset value also changes greatly with this, every time one round measurement is performed, all the channels CH1 to CH8 are measured. Since the offset value is newly specified, the offset adjustment process can be performed sufficiently accurately even if the offset value changes greatly.

  Further, according to the measuring apparatus 1, the temperature change rate Tr is sufficiently small by measuring the voltage value V in the third mode when the temperature change rate Tr is equal to or smaller than the second reference value smaller than the first reference value. When the change of the offset value is also sufficiently small, the new specification (update) of the offset value for all the channels CH1 to CH8 is omitted, so that the processing time can be further shortened, so that continuous measurement is performed. The processing speed can be further improved.

  In addition, this invention is not limited to said structure. For example, although the example applied to the measurement apparatus 1 including the input unit 11 of 8 channels CH1 to CH8 has been described above, the present invention can be applied to various measurement apparatuses including an input unit of arbitrary plural channels CH. Further, the example in which the offset value is newly specified only for one channel CH during one round measurement in the first mode has been described above. However, the channel CH for newly specifying the offset value during one round measurement is described. The number of channels is not limited to this, and may be arbitrarily changed within the range of 2 or more of the channels to be measured (eight in this example) to 7 (the number of all channels to be measured-1) or less. Can do. In this case, in this example, all of the channels CH1 to CH8 are to be measured. However, when six channels (for example, channels CH1 to CH6) are used for measurement among the eight channels CH1 to CH8, the channels to be measured. The number can be arbitrarily changed within a range of 2 or more of 5 (6 in this example) (the number of all channels to be measured-1). Moreover, although the example which measures a voltage was mentioned above, various physical quantities, such as an electric current, temperature, resistance, humidity, and flow volume, are contained in the physical quantity in this invention.

1 is a configuration diagram showing a configuration of a measuring device 1. FIG. 5 is a flowchart of a measurement process 50. It is explanatory drawing for demonstrating the method of an offset adjustment process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measuring apparatus 2 Switching part 3 Signal processing part 4 Temperature detection part 5 Control part 11 Input part Dm Measurement data Do Offset data Sm1-Sm8 Measurement object signal Tr Temperature change rate V Voltage value

Claims (4)

A switching unit for switching and outputting a plurality of measurement target signals respectively input from a plurality of channels one by one by channel switching, and an amplification process with an amplification factor corresponding to the channel for the measurement target signals output from the switching unit A signal processing unit that executes predetermined signal processing, and calculates a predetermined physical quantity based on the processing signal that has been signal-processed by the signal processing unit while causing the switching unit to perform the channel switching, and the signal processing unit A controller that specifies an offset value due to electrical characteristics for each channel and adjusts the calculated value of the physical quantity based on the offset value, and is configured to repeatedly execute the measurement of the physical quantity. Measuring device,
The control unit performs measurement of the physical quantity based on the processing signals for all the channels once when a predetermined condition is satisfied, while performing one round measurement once for all the channels. The physical quantity is measured in the first mode in which the offset value is newly specified only for some of the channels, and the offset values for all the channels are newly specified during the round measurement. Measuring device to perform.   The measurement apparatus according to claim 1, wherein in the first mode, the control unit newly specifies the offset value only for one channel while performing the round measurement once. A temperature detecting unit for detecting the temperature of at least one of the inside and the surrounding of the measuring device;
When the rate of change of the temperature detected by the temperature detection unit exceeds a first predetermined value, the control unit newly sets the offset values for all the channels each time the round measurement is performed once. The physical quantity is measured in the second mode to be specified, and the physical quantity is measured in the first mode on the assumption that the predetermined condition is satisfied when the change rate of the temperature is equal to or less than the first predetermined value. Item 3. The measuring device according to item 1 or 2.   The said control part performs the measurement of the said physical quantity in the 3rd mode which omits the new specification of the said offset value, when the rate of change of the said temperature is below the 2nd predetermined value smaller than the said 1st predetermined value. Item 4. The measuring apparatus according to Item 3.

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