JPS61222322A - Analog-digital signal converter - Google Patents

Abstract

PURPOSE:To decrease the number of transducers by activating the transducer inputting the output of an input classification circuit and a scanner having plural analog signal inputs while the conversion mode is switched in response to the input classification. CONSTITUTION:Scanners D1, D2 have plural analog inputs respectively. Input classification circuits E1, E2 output a classification signal and a range selection signal in response to the analog input classification. The scanners D1, D2 have different scan periods respectively. The transducer F1 converts the output of the scanners D1, D2 by using the conversion mode and range set by the output of the circuits E1, E2. The analog output of the transducer F1 is converted into a digital output by an A/D converter H. Thus, plural input signals are converted by using one transducer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an analog/digital signal converter that converts various analog signals such as current input, voltage input, and resistance input into digital signals.

FIG. 1 shows a conventional example. In the figure, A1...-AN are transducers each having one analog signal input terminal, B is a scanner that inputs the output analog signal of transducer A1...AN, and C is a scanner that inputs the output analog signal of scanner B. This is an A/D converter that inputs the signal and converts it into a digital signal. The transducers A, . . . AN convert various analog signals such as current input, voltage input, and resistance input into one type of analog signal (for example, voltage). The scanner B inputs the signals from the transducers A1...A to the A/D converter C in time series for each transducer A1...AN. The A/D converter C converts the analog signal for each transducer input from the scanner B into a digital signal in time series.

This conventional example has the following problems. That is, since one transducer corresponds to one input analog signal, many transducers are required when there are many inputs. Moreover, if there are multiple types of input analog signals (current, voltage, resistance, etc.), transducers with correspondingly different specifications are required.

Transducers are generally expensive, and when a large number or types of transducers are used, the overall cost becomes extremely high and the installation space is also very large.

An object of the present invention is to provide an analog/digital signal converter that uses fewer transducers and can handle various analog signals.

An embodiment of the first invention will be described based on FIG. 2. D
l is a scanner with multiple analog signal input terminals, El
is Scanner D! This is an input type circuit that determines whether the analog signal input to the range is current, voltage, resistance, etc.
θ~10V, 0~5V, 0~20mA, N15
00, N i 1000, etc.). F] is a transducer which inputs the output analog signal from the scanner D and also receives the type signal from the input type circuit El.

Conversion mode (current/voltage) depending on range selection signal.

resistance/voltage, voltage/voltage, etc.) and range.

That is, this transducer F1 incorporates conversion mode switching means and range switching means. H is an A/D converter which inputs the output analog signal of the transducer and converts it into a digital signal. D2 is a second scanner, E2 is a second input type circuit, and these are intended for input analog signals having a scan period different from that of the input analog signal of the scanner Dl.
2. The configurations of the input type circuit E2 and the relationship between them and the transducer F1 are similar to those of the input type circuit E1 of the scanner D11. Scanner Dt, D2. A/D
The converters H are each controlled by a central processing unit (CPU) of a microcomputer.

According to this embodiment, since the transducer F1 is shared and unified for a plurality of input analog signals, the structure is much simpler than the conventional example even if an input type circuit El is provided, resulting in a significant cost reduction. and space reduction can be achieved.

Note that the second scanner D2. An embodiment in which the input type circuit E2 is omitted is also an embodiment of the first invention.

An embodiment of the second invention will be described based on FIGS. 3 and 4. This is the third scanner D3. Input type circuit E3. In addition to adding a transducer F2, a range switching circuit G is also added. The scanner D3 handles multiple analog signals whose levels are significantly different from those handled by the scanners DI and D2, and the scanner D3. Input type circuit E
The configuration of the 3° transducer F2 and the related configuration between them is similar to that of the scanner D1. Type circuit E1. It is similar to that of transducer F1. The range switching circuit G selectively inputs the output analog signals of both transducers F, F2, and maintains the output at a substantially constant level according to the output signal level set in advance for each transducer Fl, F2. Switch the range so that A
/D converter H outputs a signal. Both the third scanner D3 and the range switching circuit G are controlled by the CPU.

Next, the operation will be explained based on the flowchart shown in FIG. In step (2), the void number of the scanner D1 is set. Input waiting time at step ■ 7 w 1
cent. Start the wait timer in step ■. In step (2), it is determined whether the waiting time T w 1 has ended. If it has not been completed, the process moves to step (2), and it is determined whether or not the input point of the scanner D3 has been completed. If it has not finished, move to step ■ and scan the scanner D3.
Set the point number. In step 3, the input waiting time T w 3 is set. Twl>7w3. Start the wait timer in step ■. In step (2), it is determined whether the waiting time 7'w3 has ended. If the process has not been completed, the process moves to step [phase] and the pond process is executed until the process is completed. This processing time 'ro is 7w3>To. If the waiting time Tw3 has ended, the process moves to step (2), where the range switching circuit G is switched and the output of the transducer F2 is input to the A/D converter H. In step @, A/D converter H starts converting.

At the step [phase] Ill! Start the timer T W 2.

7' 0 > TW 2. Data is read in step [phase], and the input point number of scanner D3 is incremented by 1 in step [phase]. Then return to step ■.

When the waiting time Tw1 ends in step ■, step [
phase], the range switching circuit G is switched and the output of the transducer F1 is input to the A/D converter H. At step O, the A/D converter H starts converting. In step [phase], a timer with time limit Tw2 is started. Data is read in step 0, and the input point number of scanner D1 is incremented by 1 in step [phase].

In step 0, it is determined whether or not the input point of the scanner D1 has been completed. If the process has not been completed, the process returns to step (2), and if it has been completed, the process proceeds to step [phase] and the process by the scanner D2 is performed in the same manner as the process by the scanner D.

In addition, 7w1=1sec, 7w3=100m
5ec, TO=l Om5ec, 7w2=
100 ttsec is given as an example.

As described above, each group of inputs to each scanner D1...D3 is treated independently.

Even if the transducer has an operation delay, it is possible to establish the transducer output while the inputs of other input groups are being A/D converted, and the A/D conversion is completed. After that, the established data can be subjected to A/D conversion immediately after range switching. In other words, processing efficiency of various analog signals can be improved.

In this embodiment, a fourth scanner, with input type circuitry added in association with transducer F2, or conversely, a second scanner D2. An embodiment in which the classification circuit E2 is omitted is also an embodiment of the second invention.

Although the embodiments have been described above, the analog/digital signal converter of the first invention includes a scanner having a plurality of analog signal input terminals, an input type circuit for classifying analog signals input to the scanner, a transducer that receives an output analog signal from the scanner and converts the input analog signal into a predetermined quantity of electricity by switching a conversion mode according to a type signal from the input type circuit; and an output of this transducer. It is equipped with an A/D converter that inputs an analog signal and converts it into a digital signal.

According to this first invention, since a single transducer is shared for a plurality of input analog signals, the structure can be greatly simplified compared to the conventional example, even though an input type circuit is provided. This has the effect of achieving significant cost and space savings.

Further, the analog/digital signal converter of the second invention includes a scanner having an input terminal for a plurality of analog signals, and a scanner having an input terminal for a plurality of analog signals whose levels are significantly different from those of the plurality of analog signals. , an input type circuit for classifying analog signals inputted to each scanner and provided for each scanner; and an input type circuit for inputting output analog signals from each scanner and corresponding to each scanner. It switches the conversion mode according to the type signal and converts the input analog signal into a predetermined electrical quantity.The transducer provided for each scanner and the output analog signals of both transducers are selectively input. A range switching circuit that switches the range so that the output is at a nearly constant level according to the output signal level preset for each transducer, and an analog signal output from this range switching circuit is input and converted into a digital signal. The device is equipped with an A/D converter.

According to the second invention, it is possible to collectively handle a group of input analog signals whose levels differ significantly from each other, while achieving the same effects as the first invention,
Moreover, time-divisional signal processing also has the effect of improving processing efficiency.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional example, Fig. 2 is a block diagram of an embodiment of the first invention, Fig. 3 is a block diagram of an embodiment of the second invention, and Fig. 4 is a flowchart thereof. .

Claims (2)

[Claims] (1) A scanner with multiple analog signal input terminals,
This scanner includes an input type circuit that types the analog signal input to the scanner, and an input type circuit that inputs the output analog signal from the scanner and switches the conversion mode according to the type signal from the input type circuit to convert the input analog signal into a predetermined type. A transducer that converts into electrical quantity and A that inputs the analog signal output from this transducer and converts it into a digital signal.
/D converter. (2) A scanner that has a plurality of analog signal input terminals, a scanner that has a plurality of analog signal input terminals that have significantly different levels from the plurality of analog signals, and a classification of the analog signals input to each of the scanners. It inputs the input type circuit provided for each scanner and the output analog signal from each scanner, and switches the conversion mode according to the type signal from each input type circuit corresponding to each scanner. It converts an analog signal into a predetermined amount of electricity, and it selectively inputs the transducer provided for each scanner and the output analog signals of both transducers, and outputs according to the output signal level set in advance for each transducer. An analog/digital signal converter comprising: a range switching circuit that switches the range so that the range is at a substantially constant level; and an A/D converter that inputs an analog signal output from the range switching circuit and converts it into a digital signal.