JP2005025680A - Method and device for fetching bcd signal to controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for precisely fetching a BCD signal to a controller regardless of the presence of a strobe signal or reading process in a change in voltage. <P>SOLUTION: The device for fetching the BCD signal to the controller comprises a data matching property check processing means S2 for executing determination step S23 of determining whether or not the BCD signal outputted from a BCD transmission device to the controller is identical in a plurality of reading processes S21 and S22, and output step S24 of performing, when the signal is identical as the result of determination, a decimal conversion process thereto followed by outputting, and outputting the nearest established value when it is not identical. According to this, normal data can be outputted to the outside, and output of abnormal data can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a controller fetching method and apparatus for fetching a BCD (Binary Coded Decimal) signal and performing arithmetic processing.

FIG. 3 is a block diagram showing a connection state between the BCD transmitter and the controller.
In the figure, 1 is a BCD transmission device for generating a BCD signal, such as a counter or an encoder, 2 is a transmission path for the BCD signal output from the BCD transmission device 1, 3 is a controller for processing the BCD signal, and 4 is an input / output interface. It is.
The BCD signal output from the BCD transmission device 1 passes through the transmission path 2 and is input to the controller 3 via the input / output interface 4.
A processing flow of the BCD signal input to the controller 3 is shown in FIG.
In FIG. 4, an input BCD signal is converted into data used in the controller 3 in an input signal reading processing step S11, and converted into a decimal number in a BCD → decimal number conversion processing step S12. The result is output to the outside in the output signal processing step S13, and the process returns to the input signal reading processing step S11. Such a cycle process is performed in the controller 3.
The data converted into the decimal number is used for calculation of a difference in form output such as numerical display data and flow rate.

  Japanese Patent Laid-Open No. 6-187125 (Patent Document 1) discloses a method for determining whether or not data converted into a decimal number belongs to a preset numerical range. This is a decoding means for converting each digit of the BCD data into a decimal value, and determining whether the converted decimal value of each digit is larger or smaller than each of 1 to 8 at most. And a means for outputting a signal, and using the output of the decoding means and the magnitude determination signal, it is determined whether or not the decimal value indicated by the BCD data belongs to a preset numerical range.

JP-A-6-187125

Normally, the BCD signal is composed of numerical data and a strobe signal (data readable signal) as shown in FIG. 5, but when this strobe signal is shorter than the one-cycle processing time of the controller 3, the strobe signal itself is There may be no. In this case, since the BCD signal is a voltage signal, as shown in FIG. 6, when the input signal reading process step S11 of the controller 3 is performed when the voltage signal changes, the controller cannot acquire normal data. For this reason, an external instrument is provided, and the signal is captured by the external instrument in such a manner that the BCD signal can be captured by the controller. However, it is necessary to provide another device called an external instrument, which complicates the configuration and increases costs.
Furthermore, the method disclosed in the above-mentioned Patent Document 1 relates to the processing after the BCD signal is normally captured, and does not provide a countermeasure when the data cannot be captured normally.
Therefore, an object of the present invention is to provide a method and an apparatus that can correctly import a BCD signal into a controller regardless of the presence / absence of a strobe signal and the reading process at the time of voltage change.

In order to solve the above-mentioned problem, the controller fetching method of the BCD signal according to the present invention determines whether or not the BCD signal output from the BCD transmitter to the controller is the same in a plurality of reading processes, A decimal conversion process is performed and output, and if they are not the same, the latest established value is output.
Further, the BCD signal controller fetching apparatus of the present invention includes a determination step for determining whether or not the BCD signal output from the BCD transmitter to the controller is the same in a plurality of reading processes, and a result of the determination in the determination step, If they are the same, a data consistency check processing means is provided for executing a decimal number conversion process and outputting, and if not the same, an output step for outputting the latest established value is provided.

In the present invention, as described above, by performing the data consistency check process of the present invention, normal data can be output to the outside, and abnormal data is output in a difference calculation for report output such as flow rate. Can be prevented.
Moreover, since the data consistency check process of the present invention does not select a controller or a BCD transmitter, it is effective in remodeling existing equipment or updating instrumentation instruments.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a flowchart of processing inside the controller according to the embodiment of the present invention. The connection state between the BCD transmitter and the controller is the same as that shown in FIG.
In FIG. 1, in the input signal read processing step S <b> 1, the BCD signal output from the BCD transmission device 1 is replaced with data used inside the controller 3. In the next data consistency check processing step S2, data consistency is checked by the following method.
That is, the inputted BCD signal X is stored as X _N in a memory means (not shown) in the controller 3 (step S21), and when the BCD signal X _N taken in the next cycle processing is taken into the memory means, Replace the previous value with X _(N-1) (step S22). This is repeated by a plurality of cycle processes.

For example, if the number of multiple times is 3,
X _(N-3) = X _(N-2) → A
X _(N-2) = X _(N-1) → B
X _(N-1) = X _N → C
When the conditions A, B, and C are satisfied, that is, when the same value is read three times in succession, it is determined that the data is normal (step S23), and the output memory (not shown) is updated with X _N And output.
The number of times depends on the change period of the BCD signal and the cycle time of the controller.
If the data consistency is normal, the next BCD → decimal number conversion processing step S3 is executed, and the result is output to the outside in the output signal processing step S4.
If the data consistency is not normal and the condition is not satisfied, the process of step S3 is not performed, and the most recent condition satisfaction data is output until the condition is satisfied.

By performing this data consistency check processing step S2, abnormal data is not output to the outside.
A specific example of this data consistency check processing step S2 is shown in FIG. FIG. 2A shows a generalized example, and FIG. 2B shows an output signal when the actual input signal changes to 3, 4 and 5. FIG.
As described above, according to the present embodiment, the data consistency check process is performed inside the controller, thereby checking the consistency of the BCD signal in a plurality of reading processes. Normal data can be detected regardless of the presence or absence of a signal and the reading process when the voltage changes.

  The present invention is used as a controller that can output normal data to the outside by preventing the output of abnormal data by performing a data consistency check process of a BCD signal, for example, for calculating a difference in a form output such as a flow rate. be able to.

It is a flowchart of the process inside the controller of embodiment of this invention. It is explanatory drawing of the data consistency check process and output example of this invention. It is a block diagram which shows the connection state of a BCD transmission apparatus and a controller. It is a flowchart which shows the process inside the conventional controller. It is explanatory drawing of the strobe signal contained in a BCD signal. It is a time chart at the time of a BCD voltage signal change.

Explanation of symbols

1 BCD transmitter 2 Transmission path 3 Controller 4 Input / output interface

Claims (2)

  It is determined whether or not the BCD signal output from the BCD transmitter to the controller is the same in a plurality of reading processes, and if it is the same, a decimal number conversion process is performed and output. If not, the latest established value is output. A method for fetching a BCD signal from a controller. If the BCD signal output from the BCD transmitter to the controller is the same in multiple reading processes, and if the result of the determination in the determination step is the same, the decimal conversion process is performed and output. A controller for capturing a BCD signal, comprising: a data consistency check processing means for executing an output step for outputting the latest established value if not the same.

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