JP3095576B2 - Communication error detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication error detecting device, and more particularly to a communication error detecting device applied to a receiving device such as a communication system used for communication control of a plant.

[0002]

2. Description of the Related Art In general, in this type of communication system, an error occurs in communication data due to an inappropriate termination method for a communication device constituting a network, signal reflection or external noise generated by disconnection of a communication cable, and the like. I do. In order to detect such a communication abnormality, a method of adding an error control code to communication data and making a determination on the receiving side, or a method of collating transmission data with reception data have been conventionally used.

[0003]

In the above-described conventional communication error detection method, a basic bit error can be detected, but a bit error due to noise mixing between two adjacent bits of serial data is detected. Was difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a communication abnormality detecting device capable of detecting a bit error between two adjacent bits of serial data. Aim.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a communication system for transmitting serial data as communication data by a protocol having an interval of a predetermined value or more from the end of communication to the start of the next communication. In the communication abnormality detection device that detects on the receiving side, when the pulse width of the serial data is W and the cycle is T, the pulse width is (T− W) an abnormality detection reference signal generator for generating an abnormality detection reference signal, and generating an abnormality detection signal when a pulse is detected in the serial data during a period in which the abnormality detection reference signal is being generated. And a communication end detector for detecting the end of communication of the communication system and stopping the reference signal generator for abnormality detection. Characterized in that it.

[0006]

The reference signal generator for abnormality detection which operates until the end of communication is detected by the end-of-communication detector uses the first pulse of the serial data as a trigger for the pulse width W and the period T of the serial data. Cycle T after time W
Generates an abnormality detection reference signal having a pulse width (T-W). The period during which the abnormality detection reference signal is generated corresponds to a transition period TW from a bit of serial data to the next bit. Therefore, if a pulse is detected in the serial data during the period (transition period) during which the abnormality detection reference signal is generated, the pulse is detected as an abnormal data due to a bit error between two adjacent bits of the serial data. Is detected by the abnormality detector.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a communication abnormality detection device according to one embodiment of the present invention. This embodiment is applied to a receiving side in a communication system in which serial data is transmitted as communication data by a protocol having an interval of a predetermined value or more from the end of communication to the start of the next communication because there is an upper limit in the maximum amount of communication data at one time. Is done.

In FIG. 1, a receiving device 1 receives communication data 11 serially transmitted from a transmitting side, and generates serial data (pulse train) 12 corresponding to the communication data 11. The pulse width of each pulse of the serial data 12 is W, and the cycle is T. The serial data 12 is input to the communication abnormality detection device 2 and the reception signal processing device 6.

The communication abnormality detecting device 2 comprises an abnormality detection reference signal generator 3, an abnormality detector 4, and a communication end detector 5. The abnormality detection reference signal generator 3 uses the first pulse of the serial data 12 as a trigger and sets a period T after W time.
Generates an abnormality detection reference signal 13 having a pulse width of (T−W) and sends it to the abnormality detector 4.

The abnormality detector 4 receives an abnormality detection reference signal 13
When a pulse is detected in the serial data 12 during the period in which the error occurs, an abnormality detection signal 14 is generated and sent to the communication end detector 5.

The communication end detector 5 generates a communication end detection signal 15 when the communication end of the communication system, that is, the end of one communication of the serial data 12 is detected. When the communication end detection signal 15 is generated, the abnormality detection reference signal generator 3 stops.

The reception signal processing device 6 receives the serial data 12 output from the reception device 1 and the abnormality detection signal 14 from the abnormality detector 4 and converts the serial data 12 into a serial data 12 while the abnormality detection signal 14 is being generated. The included pulses are
It will be determined to be due to an error.

FIG. 2 is a circuit diagram more specifically showing FIG. The abnormality detection reference signal generator 3 includes a flip-flop (F / F) 31, an unstable multivibrator 32,
It comprises an ND circuit 33 and a delay element. The abnormality detector 4 includes an AND circuit 41. The communication end detector 5
It comprises counters 51 and 52, a clock generator 53, a NOT circuit 54 and an AND circuit 55.

When the first pulse of the serial data 12 is output from the receiving apparatus 1, the flip-flop 31 is set by using this pulse as a trigger. As a result, the unstable multivibrator 32 has a period T and a pulse width (T−W).
To generate a square pulse 35. Flip-flop 3
Since 1 is set, the square pulse 35 passes through the AND circuit 33 and is input to the delay element 34, where it is delayed by the time W, and then input to the abnormality detector 4 as the abnormality detection reference signal 13. You.

Here, if a pulse is output from the receiving apparatus 1 during the period when the abnormality detection reference signal 13 is at the H level, that is, a pulse due to noise mixing between the original pulse of the serial data 12 and the like is generated. If there is, the output of the abnormality detector 4 becomes H level, which becomes the abnormality detection signal 14.

On the other hand, triggered by the start of the pulse generation of the serial data 12, the clock 56 from the clock generator 53 of the counters 51 and 52 in the communication end detector 5 is used.
Is also started. The counters 51 and 52 are
The pulse 56 of the serial data 12 is used as a trigger to count the clock 56 sequentially from 0 until the next pulse is input. When the next pulse is input, the clock 56 is reset and starts counting from 0 again.

[0017] When the count value of the counter 51, 52 reaches a predetermined value indicating the end of communication, Q _B terminal is the H level of the counter 52, the Q _C terminal becomes L level, NOT circuit 54
And a communication end detection signal 15 via the AND circuit 55. The flip-flop 31 in the abnormality detection reference signal generator 3 is reset by the communication end detection signal 15, and the operation of the abnormality detection reference signal generator 3 is stopped to prepare for the subsequent communication.

[0018]

As described above, according to the present invention, it is difficult to detect two serial data adjacent to each other in the prior art.
It is possible to easily detect a bit error caused by noise mixing between two bits.

Further, the communication abnormality detecting device according to the present invention comprises:
It is particularly effective in detecting in real time an error generated in communication data due to an inappropriate terminal method for a communication device constituting a network of a communication system, a reflection of a signal generated due to a disconnection of a communication cable, or an external noise. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a communication abnormality detection device according to one embodiment of the present invention.

FIG. 2 is a circuit diagram more specifically showing the communication abnormality detection device of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Receiving apparatus 2 ... Communication abnormality detection apparatus 3 ... Abnormality detection reference signal generator 4 ... Abnormality detector 5 ... Communication end detector 6 ... Received signal processing apparatus 11 ... Communication data 12 ... Serial data 13 ... Abnormality detection reference Signal 14 ... Abnormality detection signal 15 ... Communication end detection signal 31 ... Flip-flop 32 ... Astable multivibrator 33 ... AND circuit 34 ... Delay element 35 ... Pulse 41 ... AND circuit 51 ... Counter 52 ... Counter 53 ... Clock generator 54 ... NOT circuit 55… AND circuit 56… Clock

Claims (1)

(57) [Claims] 1. A communication error detecting device for detecting a communication error on a receiving side in a communication system for transmitting serial data as communication data according to a protocol having an interval of a predetermined value or more from the end of communication to the start of the next communication. Is the pulse width of W and the cycle is T, and the first pulse of the serial data is used as a trigger to generate an abnormality detection reference signal having a pulse width of (T−W) with a cycle T after time W. A reference signal generator, an abnormality detection signal generator that generates an abnormality detection signal when a pulse is detected in the serial data while the abnormality detection reference signal is being generated, and communication termination of the communication system. And a communication end detector for stopping the abnormality detection reference signal generator and detecting the abnormality.