JPS63148121A - Input signal converting device - Google Patents

Abstract

PURPOSE:To perform efficient input signal conversion with small-sized constitution by sending the output of a control part to plural multiplexers through a channel selection line and performing disconnection abnormality detection for a signal input system and an input signal data processing at the same time. CONSTITUTION:One of thermoelectromotive forces generated by thermocouples 10, 11...12 is selected through compensating leads 13, 14...15 and filter parts 7, 8...9 and led to an analog multiprocessor 4. A signal line 20 which selects an input channel by this processor 4 is outputted from a CPU control part 1 and consists of three control signal lines when there are eight input channels. Then one of the input channels is selected according to the logical combination of the lines 20, and the detection signal of one of the thermocouples 10...12 is sent to a data processing part 2, whose output is supplied to the input terminal of the control part 1. At the same time, the output of the control part 1 supplies from an analog multiplexer 4 to multiplexers 5 and 6, so the disconnection of compensating leads and thermocouples can be detected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an input conversion device, and more specifically, to a digital input conversion device that can process analog quantity data supplied from detection means arranged at a large number of measurement points by a computer or the like. The present invention relates to an input signal conversion device that converts signals into signals and detects abnormalities in an input system including detection means.

[Prior Art] Conventionally, methods for detecting abnormalities in this type of input signal converter include the method shown in FIG. 3 disclosed in JP-A-55-117932, and the method shown in FIG. 4 disclosed in JP-A-55-60828.
Something like the one shown in the figure is known.

FIG. 3 shows an example in which one thermocouple disconnection detection circuit is provided for one thermocouple serving as a detection means.
It is connected to the control device 303 via. Control device 3
03, the thermocouple disconnection detection circuit 308 and the filter section 30
5, the thermoelectromotive force from the thermocouple 301 is input to the data processing unit 304 for measurement processing.

The thermocouple disconnection detection circuit 308 includes resistors 309 and 310 and a battery 311. In addition, the filter section 30
5 shows the case of a primary filter including an i resistor 308 and a capacitor 307.

In this configuration, the thermocouple 301 generates a thermoelectromotive force e (V) between the terminals AB based on the temperature of the constant object. This electromotive force is guided between the input terminals CD of the control device 303 by the compensating conductor 302.

Here, the circuit resistance value of the compensation conductor 302 is r+(
Ω), r2 (Ω), and the resistance 3 of the thermocouple detection circuit 308
The resistance values of 09 and 310 are R1 (Ω) and R2 (Ω
), the electromotive force of the battery 11 is E (V), and the terminal EF
Of the voltage ■ applied between the thermocouple disconnection detection circuit 30
The human error δ due to the insertion of
Normally (r, +r2')'-z is several Ω to several lOΩ, and e=several 10 mV, so δ is on the order of 10-' to 10-', so small that it can be almost ignored. Therefore, it can be said that there is no problem in normal measurements.

Here, when the thermocouple 301 or the compensation conducting wire 302 is disconnected, the electromotive force E (V) of the battery is applied between the terminals EF. At this time, a voltage that is an order of magnitude higher than the normally applied voltage such that E>e is applied between EF and, therefore, the data processing unit 304 can determine that a disconnection has occurred.

Next, a conventional example shown in FIG. 4 will be explained. The conventional example shown in the figure is a device in which thermocouples 405 as detection means are arranged at many positions of a measurement target and conversion is performed on multi-point inputs. Here, the terminals of the thermocouples 405 are connected to a scanner 401 that selects human input signals (electromotive force) from the plurality of thermocouples 405 . The electromotive force of the thermocouple 405 selected by the scanner 401 is
02 to the input processing unit 403. The human processing unit 403 includes a filter that removes noise from the electromotive force data from the thermocouple 405 and an A/D converter that converts the electromotive force data into digital values. Human power processing section 4
The digital data converted by 03 is processed by the next stage data processing device 404.

Further, the data processing device 404 performs data processing for temperature measurement, and also performs control to update input data of the scanner 401 via a control line 406.

Furthermore, the path that forms a closed circuit with the thermocouple 405 via the compensation conductor 402, that is, the circuit of contact 407-resistor R2-power supply E-contact 407, measures the voltage between the thermocouple 405 and the thermocouple 405 or This is to detect a disconnection of the compensation conducting wire 402.

In such a configuration, the thermal lightning pair 405 and the compensation conductor 40
When 2 is normal, that is, when there is no abnormality such as disconnection,
Voltage E2. Resistor R2, interlocking contact 407. Power flows through a closed circuit including the thermocouple 405. Here, the interlocking contact 407 is opened and closed by separately provided means.

At this time, since the DC resistance value of the thermocouple is small, the electromotive force e of the thermocouple 405 is generated in the manual processing unit 403.

In addition, a voltage that is the sum e2 of the voltage drop across the resistor R2 and E2 is applied, that is, a voltage e, +02.

Note that the resistance R2 is set to a value that does not cause overscaling when el+e2 is manually input to the data processing device 404 via the manual processing unit 403.

On the other hand, thermocouple 405. Compensation conductor 402. When a disconnection occurs in that circuit, no current flows to the thermocouple 405 side, and an input that scales over is applied to the data processing unit 404 via the voltage E2 or resistor R2 and the human power processing unit 403. Accordingly, the data processing unit 404 detects whether there is an abnormality such as a disconnection.

[The problem that the invention attempts to solve]

However, the conventional example described above based on FIGS. 3 and 4 has the following problems. That is, (1) Regarding the conventional example shown in FIG. +r2) becomes a dog relative to R2, and the magnitude of the error δ cannot be ignored. Therefore, in order to reduce the value of (r, +r2), for example, it may be possible to make the compensation conductor 302 a little thicker, but this would increase the price and especially if a large number of thermocouples are manually operated. However, it cannot be said that determining the thickness of the compensating lead wire according to its length is efficient in terms of cost, device configuration, etc.

(2) Regarding the conventional example shown in Figure 3, if a disconnection detection circuit 308 as shown in the figure is used, when manually processing a large number of thermocouples, it is necessary to use the same number of batteries as the number of thermocouples. Therefore, the gB becomes larger and more expensive.

('l) On the other hand, in the conventional example shown in FIG. 4, since the scanner 401 is disposed between the compensation conductor 402 and the thermocouple 405, It has a two-stage device configuration including the scanner 401 side, and this fruiting device is expensive.

(4) Also, regarding the conventional example shown in Figure 4, in the circuit configuration shown in the figure, one point is selected by the scanner 401 for multiple points of human power, so processing of human power data and disconnection detection processing is required. cannot be executed at the same time, which increases the processing time in the manual measurement process.

(5) Furthermore, when using a configuration such as the scanner 401 in relation to the conventional example shown in FIG. It becomes a problem.

([i) If a mercury relay or other device with low contact resistance is used for the interlocking contact 407, the price will be high; if a relatively inexpensive analog multiplexer (analog switch) such as C-MOS is used, the internal~! 0
Since there is a discharge of the capacitor charge of the 5FET, the 5th
As shown in the figure, there is a possibility that crosstalk noise may be generated, and it is necessary to perform processing that takes into consideration the time period t between the amount of crosstalk noise generation.

In view of the above-mentioned conventional problems, the present invention provides an inexpensive input signal conversion device that is small, explosion-proof, and safe, and capable of simultaneously detecting disconnection abnormalities in a human signal system and processing human signal data. The purpose is to

(Means for Solving the Problems) Therefore, in the present invention, the
a detection means for detecting a conditioner to be measured; a first selection means for selecting one of the signals detected by the plurality of detection means; and converting and processing the signal selected by the first selection means. a processing means, a second selection means for selectively supplying a predetermined signal to a plurality of detection means, and a predetermined signal supplied via the detection means selected by the second selection means; A determination means for determining the presence or absence of an abnormality in the selected detection means, and a selection command signal for instructing the first selection means to select one of the detection means, and a selection command signal for instructing the first selection means to select one of the detection means, as well as a determination means for determining the presence or absence of an abnormality in the selected detection means; The feature 1v is that the second selection means includes a selection command means for causing the second selection means to select one of them.

[Operation] With the above configuration, the first and second selection means select different detection means according to the selection command signal of the selection command means, so that the human data from one of the detection means can be processed at the same time. determines whether there is an abnormality in the detection means.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 shows an embodiment of an input signal conversion device to which the present invention is applied.

In the figure, thermocouples 10 and 11° are used as detection means.
..., 12, a thermoelectromotive force is generated based on the temperature of the object to be measured. This generated thermal electromotive force is absorbed by the compensation conductor 13.1.
4. ..., 15. Filter parts 7, 8. ...9, for example C-MOS! It is constituted by f-conductor elements and leads to an analog multiplexer 4 which selects 12 input channels from among a plurality of thermal lightning anti-human power channels.

Generally, when measuring temperature using a thermocouple, a circuit and processing for performing reference junction compensation on the input signal are added, but these are not directly related to the present invention and are therefore omitted.

A signal line 20 for manually selecting a channel with the analog multiplexer 4 is output from the output port of the CPU control unit 1. In this case, for example, if the analog multiplexer has eight input channels, the channel selection line 18 20 only needs to be configured with three (ie, 23=8) control signal lines. By combining the logic of these three trees of control signal lines, one manual channel is selected and the thermocouples 10, 11 . . . , 12 detection signals are sent to the data processing section 2. Here, the data processing section 2 can be configured with, for example, an amplifier that amplifies a human signal, an A/D conversion circuit, or the like. The digitally converted input data is input to the manual port of the control unit 1 and processed as measured temperature data. In addition, the control unit l includes, for example, a CPU that executes processing procedures described later in FIG. 2 for processing input data and detecting abnormalities, a ROM that stores programs and fixed data corresponding to the processing procedures, and the like. It can be in the form of a one-chip microcomputer that integrally includes a RAM and the like used for processing during processing.

The manual channel selection signal 1jQ20 supplied to analog multiplexer 4 is also supplied to analog multiplexers 5 and 6. However, the logic of one control signal line of the input channel selection signal lines 20 supplied to the analog multiplexers 5 and 6 is inverted by the inverter 3.

For example, assuming that the number of manually operated channels in each of analog multiplexers 4 to 6 is 8, and therefore the manually operated channel selection signal MA20 is made up of three control signal lines A, B, and C, it is supplied to analog multiplexer 4. If the logic of the three control signal lines A, B, C of the selection signal line 20 and the manual channel numbers are made as shown in the upper part of the first table, the three of the selection signal lines 20 supplied to the analog multiplexers 5 and 6 Since the logic of C, which is one of the main control signal lines, is inverted by the inverter 3 to form C, the correspondence as shown in the lower part of Table 1 is obtained for the analog multiplexers 5 and 6.

Table 1 Therefore, for example, when channel 0 of multiplexer 4 is selected by selection signal line 20, channel 4 will be selected in multiplexers 5 and 6. Thereafter, other channels are sequentially selected manually and connected as shown in Table 1.

That is, if the human input signal on channel 0 is selected by the analog multiplexer 4, and the data processing section 2 and the control section 1 process the measured temperature data of the human input signal, during that time channel 4 is selected at the multiplexers 5 and 6. Multiplexer 6 for abnormalities such as disconnection of compensation conductor and thermocouple connected to channel 4
can be detected via Thereafter, the same process will be applied to other channels in sequence.

FIG. 2 shows an example of a procedure of manual data processing and abnormality detection processing executed by the control unit 1.

First, in step 51, channel X (in this example, X=O
~7) When the selection signal of 7) is sent using the logic shown in Table 1,
The human power data corresponding to the selected channel is supplied to the human power boat of the control section 1 via the multiplexer 4 and the data processing section 2. In the control unit 1, step S3
Then, data processing is performed on this manually inputted data to obtain information on the temperature of the object to be measured.

On the other hand, by sending the selection signal in step Sl, the analog multi-break? 5 and 6 for other channels (in this example,
+4 channel) is selected, the control unit 1 reads the logic of the channel and makes a determination.

That is, when channel 4 is selected by multiplexers 5 and 6, and there is no abnormality such as disconnection in the compensation 4 wire or thermocouple connected to it, channel 4 of multiplexer 6 receives a constant voltage from power supply 16. Vcc
A voltage of vcc-R2/(R1+R2), which is a voltage obtained by dividing the voltage (which may be a power supply voltage for driving the multiplexer 5) by the resistor 17 (R, ) and the resistor 18 (R2), is applied.

Here, the channel 4 is connected by a switch, and the output 21 of the multiplexer 6 is supplied to the human-powered boat of the control section 1 as a disconnection detection signal 21.

Therefore, the above values of Vcc, R, , R2 are such that the potential level Vcc -R2/(R++th) of the disconnection detection signal 21 supplied to the manual boat of the control unit 1 is the threshold of the logic "H" of the control unit 1. It is sufficient to set it so that it exceeds the level voltage and has an appropriate margin above it. Furthermore, the current flowing from the power supply 16 through the resistor 17, approximately cc/ (R++R2) (the resistance of the compensation lead wire and the resistance of the thermocouple are ignored as they are sufficiently small compared to R1), is It is possible to set it so that it does not become energizing.

That is, if there is no abnormality such as disconnection in the compensation conductor or thermocouple, the signal level manually input to the control unit 1 is "H",
In this case, the process proceeds to step S7, where the value of X is incremented by +1, and then the process proceeds to the next process.

On the other hand, if there is an abnormality in the compensation conductor or thermocouple, such as a disconnection, disconnection, or disconnection, the constant voltage Vcc is not applied through the multiplexer 5, so approximately the reference voltage 19 is applied to channel 4 of the multiplexer 6. , the disconnection detection signal 21 is manually input to the control unit 1 at the logic "L" level. In this case, the process proceeds to step S9, where the abnormality is detected and the operator is made aware of the occurrence of the abnormality, for example, by using an alarm means that issues an alarm by sound or display.

As discussed above, this embodiment, which makes use of the present invention, has various features as shown below.

(1) Excellent processing efficiency.

It is possible to simultaneously detect abnormalities in compensation conductors and thermocouples and measure temperatures on other human-powered channels, and even when sequentially changing the human-powered channels and performing temperature measurement and abnormality detection on each human-powered channel, the control Section 1 only needs to increment the channel counter by software, and has excellent processing efficiency.

(2) It should be inexpensive in terms of cost.

For multiplexing of input channels for multi-point temperature measurement and disconnection abnormality detection, semiconductors, especially c-! Since a 1+OS analog multiplexer is used, the cost is lower than methods using mercury relays, mechanical switches, etc.

(3) It is advantageous in terms of explosion protection.

Since C-MO5 semiconductor elements are used in analog multiplexers and other manual processing parts, conventional TT
It is advantageous in terms of explosion protection, since it is much smaller in energy than L logic or analog amplifier configurations, and there is no concern about spark discharge caused by mercury relays or mechanical switches.

(4) Being able to utilize the feature of low power.

Since the C-MO5 semiconductor element has a low current consumption and the device circuit also suppresses the current, it is possible to measure temperature using, for example, a normal battery or solar cell as a power source.

(5) There are no regulations regarding the length or thickness of the compensation conductor.

Disconnection abnormality detection is identified by the voltage level and is separated from temperature measurement, so there is no need to incorporate wiring resistance countermeasures into the circuit that take into account the length and thickness of the compensation conductor as in the conventional case. There is no need to worry about this.

(6) The circuit configuration is simple.

The circuit configuration of the device is extremely simple, and it is independent of the thermoelectromotive force filter amplifier section for temperature measurement, and channels that do not detect abnormalities are turned off and disconnected from the measurement circuit. Do not discuss measurement errors.

(7) Be able to identify the point where an abnormality is detected.

The channel selection signal of the analog multiplexer is uniquely given by the control unit 1, and the disconnection abnormality signal 21 is stored in the memory stored in the control unit 1, so it is easy to identify which manual channel point the abnormality detection point is. is possible.

Although eight thermocouple measurement points have been described in this embodiment, it is clear that the present invention can be applied to any number of measurement points.

Furthermore, the present invention is not only applicable to temperature measurement using a thermocouple, but also to other manual measurements and input devices. Furthermore, on the upper side, the multiplexer 6 is provided in the configuration shown in the first figure, or the multiplexer 6 may not be used.

Similarly to the multiplexer 5, the multiplexer 6 also has thermocouples 10, 11 . ..., 12 terminals can be connected in a matrix. In this case, only either multiplexer 5 or 6 may be provided.

[Effects of the Invention] As is clear from the above description, it is possible to realize an inexpensive input signal conversion device that is small, explosion-proof, safe, and capable of simultaneously detecting disconnection abnormalities in a human signal system and processing input signal data. can.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing one embodiment of an input signal conversion device to which the present invention is applied; FIG. 2 is a flowchart showing an example of a processing procedure for human data processing and abnormality detection according to the present embodiment; FIGS. FIG. 4 is a circuit diagram showing two examples of conventional devices, and FIG. 5 is an explanatory diagram for explaining the problems of the conventional example shown in FIG. 1.303...Control unit, 2.304,404...Data processing unit, 3...Inverter, 4.5.6...Analog multiplexer, 7.8,9
, 305... filter section, 10.11, 12, 301
,405...Thermocouple, 13.14,15,302,4
02... Compensation lead wire, 16... Power supply voltage, 17.18, 306, 309... Resistor, 19... Reference voltage, 20... Channel selection signal line, 21... Disconnection detection signal, 307.310... Capacitor, 308... Disconnection detection circuit, 311... Battery, 401...-Scanner, 103... Input processing unit, 406... Control line, 407... Grounding . Flowchart showing the processing manual page on page 1, Figure 2, Figure 5.

Claims (1)

[Claims] 1) Detection means arranged at a plurality of positions of the measurement object to detect the state quantity of the measurement object; and a detection means for selecting one of the signals detected by the plurality of detection means. a processing means for converting and processing the signal selected by the first selection means; a second selection means for selectively supplying a predetermined signal to the plurality of detection means; (2) determining means for determining whether or not there is an abnormality in the selected detecting means based on the predetermined signal supplied via the detecting means selected by the second selecting means; and one of the detecting means in the first selecting means. and a selection command means for supplying a selection command signal for commanding the selection of the second selection means and for causing the second selection means to select any of the detection means other than the detection means according to the command. Device. 2) In the input signal conversion device according to claim 1, the selection command means sends, as the selection command signal, a signal constituted by a plurality of control signal logics corresponding to the number of the detection means arranged. An input signal converting device comprising: sending means for sending the signal to the first selecting means; and logic converting means for changing the control signal logic of the signal to be sent and supplying it to the second selecting means. 3) The input signal conversion device according to claim 1 or 2, wherein the first and second selection means include a multiplexer configured using a semiconductor element. Device.