JP5637784B2 - A transmission / reception system having a function of determining a deteriorated part of a communication path by a test signal - Google Patents

Description

  The present invention relates to an apparatus for determining a deteriorated part in an optical communication path.

Devices that control motors and the like in real time, such as numerical control devices that control machine tools, perform control operations in a short cycle, and the communication path has high reliability so that a single communication error cannot be tolerated depending on the communication contents. Since there is a case where it is required, serial communication having high speed and high reliability using an optical communication path is adopted.
In applications where the reliability of the communication path is severe as described above, there is a demand for a means for preventing a system down by determining and actively replacing a deteriorated part before an abnormality occurs in the communication path. . In addition, it is desirable to determine a deteriorated part as easily and quickly as possible.

  As a technique for detecting an abnormality in an optical communication path, there are a technique for detecting a disconnection, a technique for detecting a bit error in communication data, a technique for detecting missing transmission path clocks, and the like. Patent Document 1 discloses a technique for detecting disconnection, and Patent Document 2 discloses a technique for detecting a bit error in communication data.

  Patent Document 3 discloses a technique for detecting a distortion of an optical signal and outputting a warning before an error actually occurs (see FIGS. 22 and 23). The serial data deterioration detection circuit disclosed in Patent Document 3 includes a phase detection circuit that outputs the phase difference between the phase of the rising or falling edge of the received serial data and the phase of the reference clock as phase data. When the corrected phase data, which is phase data whose phase has been adjusted by the adjustment circuit, exceeds a preset range, a warning is output. In the modified phase data, the phase variation is expressed as a numerical value.

  FIG. 23 is a flowchart for describing a procedure for performing degradation site determination using the technique disclosed in Patent Document 3. If an abnormality or a sign of abnormality is detected in the optical communication path, leave the device that includes the transmission unit subject to deterioration determination, replace the device that includes the optical fiber cable and reception unit with a normal product, and start up the system to determine deterioration. The deterioration information of the target communication path is acquired (SB01, SB02). It is determined whether or not the device including the transmission unit has deteriorated. If the device has deteriorated, the device including the transmission unit is replaced (SB03, SB04). The apparatus including the receiving unit is returned from the normal product to the degradation determination target product (SB05). The system is started up and the deterioration information of the communication path subject to deterioration determination is acquired, and it is determined whether or not the device including the receiving unit is deteriorated. If the device is deteriorated, the device including the receiving unit is replaced (SB06). , SB07). The optical fiber cable is returned from the normal product to the degradation determination target product (SB09). When the system is started up, the deterioration information of the communication path subject to deterioration determination is acquired, and it is determined whether the optical fiber cable is deteriorated. If it is deteriorated, the optical fiber cable is replaced. Is finished (SB10 to SB12).

Japanese Utility Model Publication No. 6-46116 JP 2007-208867 A JP 2010-004144 A

  In applications that require high reliability of the communication path, such as the machine tool control device described in the background art, before the abnormality occurs in the communication path, by determining and actively replacing the deteriorated part Therefore, a means for preventing the system from going down is desired. In addition, it is desirable that a deteriorated part can be determined as easily and quickly as possible.

The techniques disclosed in Patent Literature 1 and Patent Literature 2 are only for detecting that an abnormality has actually occurred, and from the viewpoint of preventive maintenance, it is impossible to detect a sign of an abnormality before the abnormality has occurred. was there. To solve this problem, the technique disclosed in Patent Document 3 detects signal degradation from the degree of phase change of received data. However, since the pattern of communication data differs depending on the configuration of the system having an optical communication path, It has been difficult to stably determine signal degradation regardless of the configuration.
In addition, in a technique in which signal degradation on the optical communication path is determined on the receiving side, it is determined which part of the optical communication cable that is a constituent part of the optical communication path is defective. It was difficult. Difficulty in identifying the degraded part of the communication path is due to the need to replace devices and parts, change the connection order, and require system settings to be changed.Therefore, maintenance work requires time and effort. There was a problem that it took.

  Therefore, the object of the present invention is not to depend on the system configuration in view of the problems of the prior art in which it is difficult to stably determine signal degradation depending on the system configuration and the identification work of the degradation portion of the communication path is difficult. A transmission / reception system having a function for determining a deteriorated part of a communication path by a test signal capable of stably determining the deteriorated part from a transmitter, a communication line, and a receiver of the communication path before a communication failure occurs. Is to provide.

The invention according to claim 1 of the present application receives a transmission circuit for transmitting a serial signal, a serial transmission path for transmitting the serial signal transmitted from the transmission circuit, and the serial signal transmitted from the serial transmission path. In a serial signal transmission / reception system having a reception circuit, a communication protocol used in serial communication transmitted / received by the transmission / reception system for determining deterioration of a communication path including the transmission circuit, the reception circuit, and the serial transmission path A test signal having a specific mark ratio determined based on the code system of the test signal is generated and output to the transmission circuit, and the reception circuit receives the test signal through the transmission circuit and the serial transmission path. The phase of the rising or falling edge of the test signal is detected and the rising edge of the test signal is detected. A phase detection circuit that outputs the phase difference between the phase of the falling edge and the phase of the reference clock as phase data, and the deterioration of the serial signal is determined based on the phase data output from the phase detection circuit. A transmission / reception system having a degradation determination function of a communication path by a test signal, comprising: a degradation determination circuit that outputs degradation determination information.

The invention according to claim 2 is an apparatus in which the transmission / reception system includes the transmission circuit, the reception circuit, the phase detection circuit, the deterioration determination circuit, and the test signal generation circuit. The serial transmission line is a transmission line directly connecting the transmission circuit and the reception circuit, and the deterioration determination circuit determines deterioration of the test signal transmitted from the transmission circuit and received by the reception circuit. A transmission / reception system having a communication path deterioration determination function using a test signal according to claim 1.
According to a third aspect of the present invention, the transmission / reception system includes a first device including the transmission circuit and the test signal generation circuit, a second circuit including the reception circuit, the phase detection circuit, and the deterioration determination circuit. 2. The system according to claim 1, wherein the apparatus is a system connected by the serial transmission line, and the deterioration determination circuit determines deterioration of the test signal transmitted from the transmission signal and received by the reception circuit. It is a transmission / reception system having a communication path degradation determination function based on the described test signal.
According to a fourth aspect of the present invention, the test signal is a signal having the highest or lowest mark ratio that can be generated as a serial communication signal transmitted / received by the transmission / reception system. A transmission / reception system having a communication path deterioration determination function based on the test signal according to any one of the above.

The invention according to claim 5 includes a switching unit that switches between transmission of the test signal and transmission of the signal for serial communication by a switching signal. This is a transmission / reception system having a communication path deterioration determination function based on the test signal.
According to a sixth aspect of the present invention, the switching signal includes a switching command received by the receiving circuit, a switching signal input from an external input signal receiving unit, a switching command input from a network-connected communication circuit, or a power supply 6. The transmission / reception system having a function for determining deterioration of a communication path by a test signal according to claim 5, wherein the transmission / reception system is a switching signal generated for a predetermined time after being turned on.

  According to a seventh aspect of the present invention, there is provided a deterioration determination information holding circuit for holding deterioration determination information output from the deterioration determination circuit, the transmission circuit, and the reception based on a determination result held in the deterioration determination information holding circuit. A transmission / reception system having a communication path deterioration determination function using a test signal according to any one of claims 1 to 6, further comprising: a circuit; and display means for displaying a deterioration state of the transmission path. is there.

  According to the present invention, regardless of the system configuration, before a communication failure occurs, the communication path of the communication path based on the test signal that can stably determine the degradation site from the transmission section, the communication line, and the reception section of the communication path. It is possible to provide a transmission / reception system having a function of determining a deteriorated part.

It is a block diagram of a control device concerning an embodiment of the present invention. It is a figure explaining an optical communication path. It is a block diagram of the process part which concerns on this invention. It is a figure explaining the optical communication path of a one-pair communication form. It is a figure explaining the optical communication path of 2 pair communication form. It is a figure explaining the connection of the transmission part of a 1-pair communication form, and a receiving part. It is a figure explaining the connection of the transmission part of a 2 pair communication form, and a receiving part. It is a figure explaining the connection at the time of the optical fiber cable degradation determination in a 1-pair communication form. It is a figure explaining the connection at the time of the optical fiber cable degradation determination in 2 pair communication form. It is a figure explaining the example 1 of the serial data for a test. It is a figure explaining the example 2 of the serial data for a test. It is a figure explaining the example 3 of the serial data for a test. It is a figure explaining the edge detection when a threshold value is normal, and the edge detection when a threshold value is low. It is a figure explaining embodiment which has a switching means of transmission data. It is a figure explaining embodiment which has a degradation determination information holding means. It is a figure explaining embodiment which has a display means of degradation determination information in a control device. It is a figure explaining embodiment which has a display means of judgment information outside the control device. It is a flowchart explaining the procedure which performs the degradation site | part determination which concerns on this invention. It is a figure explaining 7 segment LED. It is a figure explaining the distinction 1 of the transmission / reception circuit of a 2 pair communication form. It is a figure explaining the distinction 2 of the transmission / reception circuit of 2 pair communication form. It is a figure explaining the deterioration detection of the serial data in a prior art. 10 is a flowchart for explaining a procedure for performing degradation site determination using the technique disclosed in Patent Document 3;

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a control device according to an embodiment of the present invention.

For example, the device 10 that is a numerical control device that controls a machine tool includes a processing unit 12, a transmission unit 14, a reception unit 16, and a display unit 18. The processing unit 12 includes a deterioration determination circuit 120, a deterioration determination information holding circuit 121, a test data generation circuit 122, and a phase detection circuit 123. Data generated by the test data generation circuit 122 of the processing unit 12 is sent to the transmission unit 14 as serial data, and serially communicated from the transmission unit 14 to the external device as serial data. The receiving unit 16 receives serial data from an external device by serial communication, and the received serial data is acquired by the phase detection circuit 123 of the processing unit 12.
The phase detection circuit 123 detects the phase of the rising or falling edge of the test signal received by the receiving circuit via the transmission circuit and the serial transmission line, and the phase of the rising or falling edge of the test signal The phase difference from the phase of the reference clock is output as phase data.
The acquired phase data is sent to the deterioration determination circuit 120. The deterioration determination circuit 120 determines the deterioration of the phase data, and sends the deterioration determination information obtained as a result of the deterioration determination to the deterioration determination information holding circuit 121. The deterioration determination information holding circuit 121 stores deterioration determination information. The display means 18 displays the deterioration determination information stored in the deterioration determination information holding circuit 121 on the display means 18.

FIG. 2 is a diagram for explaining an optical communication path. The optical communication path includes a transmission unit, an optical fiber cable, and a reception unit. The apparatus 10 includes a processing unit 12, a transmission unit 14, and a reception unit 16. The apparatus 20 includes a processing unit 22, a transmission unit 24, and a reception unit 26. The transmission unit 14 and the reception unit 26 and the transmission unit 24 and the reception unit 16 are connected by a serial bus using optical fiber cables 6 and 8.
The transmission units 14 and 24 are composed of a transmission circuit and a light emitting unit (LED), and convert an electrical signal into an optical signal. The receiving units 16 and 26 are constituted by a light receiving unit (photodiode or phototransistor) and a receiving circuit, and convert an optical signal into an electric signal. In the transmission units 14 and 24, a stack failure or a light output decrease occurs due to a circuit failure or deterioration in characteristics of the light emitting unit. In the optical fiber cables 6 and 8, the amount of light is reduced due to stress such as physical defects, bending, and material deterioration. In the receiving units 16 and 26, a stack failure or output waveform distortion occurs due to a circuit failure, characteristic deterioration, threshold control limit, or the like.

  FIG. 3 is a block diagram of the processing unit according to the present invention. As described above, the processing unit 12 includes the test data generation circuit 122, the phase detection circuit 123, and the deterioration determination circuit 120. The deterioration determination circuit 120 is equivalent to the serial data deterioration detection circuit (see FIG. 22) in the prior art, but may be any circuit that outputs deterioration determination information based on the phase data, and the deterioration determination of the prior art described in the background art. The circuit is not limited to the circuit. In the process of transmitting and receiving various test data, both serial data and phase data input to the deterioration determination circuit change every moment. Therefore, it is desirable that the deterioration determination information holds the worst value and is output after the check is completed. .

  Each communication path includes a transmission unit, an optical fiber cable, and a reception unit. FIG. 4 is a diagram for explaining an optical communication path in a one-to-one communication mode. FIG. 5 is a diagram for explaining an optical communication path in a two-pair communication mode. The communication paths of the one-pair communication form and the two-pair communication form are irrespective of the master 30 or slave 31, 32, 33, 34, 35, 36 in FIG. 4 or the master 40 or slave 41, 42, 43 in FIG. Each device has a transmission unit and a reception unit, so that the data transmitted by the device can be received by the device by using a loop connector.

  Note that the master 30 and slaves 31, 32, 33, 34, 35, and 36 in FIG. 4 described later have the degradation information determination function described with reference to FIG. Similarly, the master 40, slaves 41, 42, and 43 in FIG. 5, the device under measurement 50 in FIG. 6, the device under measurement 60 in FIG. 7, the normal device 70 in FIG. 8, the normal device 80 in FIG. The apparatus 90 in FIG. 17 has a deterioration determination information function.

  Even if the form of the communication path is either the one-pair communication form (see FIG. 4) or the two-pair communication form (see FIG. 5), the test signal is transmitted without changing the connection, and each optical communication path Since the failure determination can be performed, the defective optical communication path can be easily narrowed down. When it is determined that a certain optical communication path is defective, in order to determine which part of the transmission section, reception section, or optical fiber cable is defective in the optical communication path, the transmission section of one device And a receiving unit (see FIGS. 6 and 7), a normal device or an optical fiber cable (see FIGS. 8 and 9), and the like, to transmit / receive test signals.

  When the deterioration determination of the transmission unit or the reception unit is performed, an optical fiber cable is connected to the apparatus as illustrated in FIGS. FIG. 6 is a diagram illustrating the connection between the transmission unit and the reception unit in the one-to-one communication mode. FIG. 7 is a diagram illustrating the connection between the transmission unit and the reception unit in the two-pair communication mode. In the connection between the transmission unit and the reception unit in the one-pair communication mode of FIG. 6, the transmission unit 51 and the reception unit 52 provided in the device under measurement 50 are connected by a normal optical fiber cable 53. Further, in the connection between the transmission unit and the reception unit in the two-pair communication mode of FIG. 7, the transmission unit 61 and the reception unit 62 provided in the device under measurement 60 are connected by a normal optical fiber cable 65, and the transmission unit 63 The receiving unit 64 is connected with a normal optical fiber cable 66.

  When it is desired to determine the deterioration of a certain device, the transmission unit and the reception unit of the device are determined to deteriorate together (see FIGS. 6 and 7), and the deterioration determination information includes the deterioration determination of the transmission unit and the deterioration determination of the reception unit Is a composite of The meaning of combining means that if one of the transmitter and the receiver is degraded, the judgment information of “transmitter + receiver” is worse, and if both are degraded, the judgment information is very bad. Is meant to be. If the acquired deterioration determination information is a value indicating a failure, it can be determined that at least one of the transmission unit and the reception unit is defective, and the corresponding device is replaced.

When determining deterioration of an existing optical fiber cable, the optical fiber cable is connected to the apparatus as shown in FIGS. FIG. 8 is a diagram for explaining connection at the time of determining the deterioration of the optical fiber cable in the one-pair communication mode. Use normal equipment and optical fiber cables other than the optical fiber cable to be measured. A transmitter 72 and a receiver 71 of a normal device 70 are connected by an optical fiber cable 73 to be measured.
FIG. 9 is a diagram for explaining the connection at the time of determining the deterioration of the optical fiber cable in the two-pair communication mode. Use normal equipment and optical fiber cables other than the optical fiber cable to be measured. Even if the optical fiber cable to be measured is an optical fiber cable for two-pair communication, the optical fiber cables 85 and 88 to be measured can be obtained by connecting the repeater 86 and the normal optical fiber cable 87 as shown in FIG. Can be determined.

  Next, test data will be described with reference to FIG. 10, FIG. 11, and FIG. FIG. 10 is a diagram for explaining Example 1 of test serial data. FIG. 11 is a diagram for explaining an example 2 of test serial data. FIG. 12 is a diagram for explaining a third example of test serial data.

Example 1 of the test serial data shown in FIG. 10 will be described. 10 includes a start sequence, an address field, a control field, an information field, a check sequence, and an end sequence.
FIG. 11 shows an example of test serial data when the lowest mark rate is 40 [%] in a certain code system. FIG. 12 shows an example of test serial data when the highest mark ratio is 80 [%] in a certain code system.
The test data may be simulated data transferred during normal communication, or may be the highest in the code system (4B5B, 8B10B, etc., see JP-A-5-336168) implemented in the communication protocol. It may be data of the lowest mark rate (see Japanese Patent Laid-Open No. 4-74030). Since the range that the corrected phase data can take varies depending on the test data, it is necessary to adjust the determination level of the deterioration determination circuit.

  If the communication frequency and the number and types of connected devices differ depending on the system configuration, the data communicated during system operation also differs. Since the phase data is affected by the communication data, it is difficult to stably determine the deterioration of the communication data when the system is operating. If the test data is used, communication data can be determined regardless of the system configuration. Therefore, it is possible to stably determine deterioration based on the same standard even in communication paths of different systems.

  Further, it is considered that the mark rate of communication data when the system is operating cannot be the lowest mark rate in the code system (4B5B, 8B10B, etc.) implemented in the communication protocol. By making the test data the data with the lowest mark rate that can be taken by the system, it is possible to determine the deterioration with a margin compared to when the system is operating. The mark rate is a ratio of “1” included in the data string.

  An example in which the mark rate of communication data affects phase data will be described. In general, a threshold control circuit is mounted on the receiving circuit of the receiving unit of the optical communication path. This is a circuit that changes the comparison voltage of the comparator in accordance with the amount of light received by the receiving unit. With this circuit, even if the length of the optical fiber cable changes or the optical fiber cable bends and the amount of light falls, the threshold value of the receiving circuit is controlled accordingly, so there is little distortion A pulse output can be obtained.

  When the reception circuit receives data with a high (or low) mark rate, it appears that the amount of light has increased (or decreased), so the reception circuit controls to increase (or decrease) the threshold value. However, since the actual light quantity has not increased or decreased, the pulse output is distorted as a result. FIG. 13 is a diagram for explaining edge detection when the threshold is normal and edge detection when the threshold is low. Even when the received data is normal, when the threshold is low or high, the edge detection position is shifted compared to when the threshold is normal, and the pulse output is distorted. Therefore, if it is desired to obtain deterioration determination information when the pulse output distortion becomes the largest, data with a high (or low) mark ratio is taken into account in consideration of the time delay until the threshold limiting circuit changes the threshold. It is necessary to transmit and receive for a sufficiently long time.

  Next, an embodiment of the present invention will be described in which the selection of whether to transmit normal communication data or test data can be switched by various inputs. FIG. 14 is a diagram for explaining an embodiment having transmission data switching means.

The apparatus 10 includes a power supply circuit 11, a processing unit 12, an external input signal reception unit 13, a transmission unit 14, a communication circuit 15, and a reception unit 16. The processing unit 12 includes a deterioration determination circuit 120, a test data generation circuit 122, a phase detection circuit 123, a communication data generation circuit 124, and a switching unit 125. The power supply circuit 11 is means for supplying power for operating the apparatus 10.
Data generated by the test data generation circuit 122 of the processing unit 12 is sent to the transmission unit 14 as serial data, and serially communicated from the transmission unit 14 to the external device as serial data. The receiving unit 16 receives serial data from an external device by serial communication, and the received serial data is acquired by the phase detection circuit 123 of the processing unit 12. The acquired phase data is sent to the deterioration determination circuit 120. Then, as described with reference to FIG. 1, the deterioration determination circuit 120 determines the deterioration of the phase data. The deterioration determination information obtained as a result of the deterioration determination is stored or displayed on the display means.

Test data is input from the test data generation circuit 122 to the switching unit 125. Communication data is input to the switching unit 125 from the communication data generation circuit 124. The switching unit 125 selects whether to transmit normal communication data input from the communication data generation circuit 124 or test data input from the test data generation circuit 122.
Switching between the normal communication data and the test data in the switching unit 125 is received from an external signal input such as a switch, a keyboard, and a pointer, a power-on signal from the power supply circuit 11, and the communication circuit 15 connected to the network. A switching command, a cable connection detection signal output from the receiving unit 16, a switching command, or the like can be considered.
Since the switching unit 125 has the timer 126, it can be used to switch to the communication data after transmitting the test data for a certain time from the one-shot input (for example, power-on).
The cable connection detection signal from the receiving unit 16 may detect a physical connection or may detect a signal input from the cable. It is also possible to give a switching command to the switching unit by the communication circuit 15, and the existing serial communication can be used as a communication means, or a separate communication circuit can be provided.

FIG. 15 is a diagram illustrating an embodiment having a deterioration determination information holding unit. As shown in FIG. 15, by having the deterioration determination information holding circuit 121 inside or outside the apparatus 10, the degree of freedom can be increased in the timing for performing the deterioration determination and the display timing of the deterioration determination information.
FIG. 16 is a diagram for explaining an embodiment in which the control device has display means for displaying deterioration determination information. The apparatus 10 includes a processing unit 12 and a display unit 18. When the device 10 has the display means 18 (screen, LED, etc.), it is possible to perform from the deterioration determination to the display of the deterioration determination information by the device alone.
FIG. 17 is a diagram for explaining an embodiment having determination information display means outside the apparatus. In the case where the degradation determination target device 20 does not have a display unit and the determination information is displayed on the display unit 98 of the device 90 outside the device, the determination information must be transmitted to the display unit using some communication unit. Don't be. If it cannot be transmitted immediately, it is temporarily stored in the deterioration determination information holding circuit 221 provided in the processing unit 22, and is transmitted and displayed as necessary.

FIG. 18 is a flowchart for explaining a procedure for performing the degradation site determination according to the present invention when an abnormality or a sign of abnormality is detected in the optical communication path. Hereinafter, it demonstrates according to each step.
[Step SA01] The transmission unit and the reception unit of the apparatus including the transmission unit subject to deterioration determination are connected with a normal product cable.
[Step SA02] The transmission unit and the reception unit of the device including the reception unit subject to deterioration determination are connected with a normal cable.
[Step SA03] A self-check (acquisition of deterioration information) is performed on each deterioration determination target device.
[Step SA04] It is determined whether or not the device including the transmission unit has deteriorated. If it has deteriorated, the process proceeds to Step SA05, and if not, the process proceeds to Step SA06.
[Step SA05] Replace the device including the transmission unit with a normal product.
[Step SA06] It is determined whether or not the device including the receiving unit has deteriorated. If it has deteriorated, the process proceeds to Step SA07, and if not, the process proceeds to Step SA08.
[Step SA07] Replace the device including the receiving unit with a normal product.
[Step SA08] The transmission unit and the reception unit of the device that is determined not to be defective are connected by the deterioration determination target cable.
[Step SA09] The device performs a self-check (acquisition of deterioration information).
[Step SA10] It is determined whether or not the optical fiber cable has deteriorated. If it has deteriorated, the process proceeds to Step SA11, and if it has not deteriorated, the process ends.
[Step SA11] Replace the optical fiber cable with a normal one, and the process ends.

  As described above, in the present invention, a normal optical fiber cable is connected to the transmission unit and the reception unit, and self-check (acquisition of deterioration information) can be performed in the apparatus main body. For this reason, self-checking of the device including the transmission unit and the device including the reception unit can be performed at the same time, and it is not necessary to replace the measurement target device with a normal product for the purpose of determining the deteriorated part. The normal optical fiber cable used for the self-check may be of a length that allows the transmitter and receiver of the apparatus to be connected and can be easily connected.

Next, a display example of the deterioration determination information will be described based on the two-pair communication mode shown in FIGS. FIG. 20 is a diagram for explaining the distinction 1 between the transmission / reception circuits in the two-pair communication mode. FIG. 21 is a diagram for explaining the distinction 2 between the transmission / reception circuits in the two-pair communication mode. A case where a comment is displayed on the screen and a case where a 7-segment LED is used will be described as display means for displaying deterioration determination information. FIG. 19 is a diagram for explaining a 7-segment LED. The 7-segment LED is a module in which seven LEDs are modularized and can express numbers and alphabets.
(1) When a comment is displayed on the screen (a) When the transmission circuit and reception circuit of one device are connected by a transmission path, the identification information of the apparatus, the identification information of the communication path, and the deterioration information are displayed.
When there are a plurality of looped communication paths, it is possible to distinguish between upstream and downstream sides.
Display example 1: There is no problem with the communication path of device A (see Fig. 6).
Display example 2: The communication path on the upstream side of device B has deteriorated, so replacement is recommended (see Fig. 20).
Display example 3: The communication path on the downstream side of device C is very deteriorated and should be replaced (see Fig. 20).
(B) When the transmission circuit and the reception circuit of the two devices are connected via a transmission path, the communication section identification information, the communication path identification information, and the deterioration information are displayed.
Display example 1: There is no problem with the communication path between device A and device B (see Figure 4).
Display example 2: The communication path sent from device C to device D has deteriorated, so replacement is recommended (see Figure 5).
(2) When displaying with 7-segment LED (a) When the transmission circuit and reception circuit of one device are connected by a transmission line Display example 1: The degree of deterioration is determined to a level of 0 to 9, Displays numbers 0-9.
Display example 2: When the upstream communication path is deteriorated and replacement is recommended, upper “U” is displayed. When the downstream communication path is deteriorated and replacement is recommended, lower “L” is displayed. If there is no problem in display, “-” is displayed (see FIG. 20).
(B) When the transmission circuit and the reception circuit of the two devices are connected by a transmission line Display example 1: When the communication path received on the upstream side is deteriorated and replacement is recommended, “U” of upper is set. If the communication path received on the downstream side deteriorates and replacement is recommended, “L” of “lower” is displayed, and “−” is displayed if there is no problem (see FIG. 21).

  Although the case where the self-check of the single device is described with reference to FIGS. 6 to 8, if the method of self-checking the communication path between the two devices is used as shown in FIGS. It is possible to determine the deterioration of the communication path using the test data in the same connection state as the time. For example, a self-check can be performed between all devices when the power is turned on, and the self-check result can be referred to from the display means after the system is started. Therefore, first, it is checked which communication path in the system is deteriorated by determining deterioration between apparatuses. Next, it is desirable to take a procedure of searching for a deteriorated part by determining deterioration of a device constituting a communication path that has been previously determined to be deteriorated by determining deterioration of a single device.

  Further, in the description so far, the example in which the deterioration determination is performed in order to find a part where a defect has occurred or is likely to occur is given, but information indicating that the deterioration has not occurred can also be obtained from the deterioration determination information. . For example, it may be used to check for deterioration in a system test before shipment, and to confirm that the quality of the communication channel of the system is at a level where there is no problem as a product (there is a sufficient margin for the deterioration level at which a failure occurs) I can.

6, 8 Optical fiber cable 10 Device 11 Power supply circuit 12 Processing unit 120 Degradation determination circuit 121 Degradation determination information holding circuit 122 Test data generation circuit 123 Phase detection circuit 124 Communication data generation circuit 125 Switching unit

13 External Input Signal Receiver 14 Transmitter 15 Communication Circuit 16 Receiver 18 Display Means

20 Device 22 Processing Unit 221 Degradation Determination Information Holding Circuit 24 Transmitting Unit 26 Receiving Unit

30 Master 31, 32, 33, 34, 35, 36 Slave

40 Master 41, 42, 43 Slave

50 Device under test 51 Transmitter 52 Receiver 53 Normal optical fiber cable

60 Device under test 61 Transmitter 62 Receiver 63 Transmitter 64 Receiver 65, 66 Normal optical fiber cable

70 Normal device 71 Receiver 72 Transmitter

80 Normal Device 81 Transmitter 82 Receiver 83 Transmitter 84 Receiver 85 Optical Fiber Cable under Measurement 86 Optical Fiber Cable Repeater 87 Normal Optical Fiber Cable 88 Optical Fiber Cable Under Measurement

Claims (7)

Serial signal transmission / reception system comprising: a transmission circuit that transmits a serial signal; a serial transmission path that transmits the serial signal transmitted from the transmission circuit; and a reception circuit that receives the serial signal transmitted from the serial transmission path In
A specific mark determined based on a code system of a communication protocol used in serial communication transmitted / received by the transmission / reception system for determining deterioration of a communication path including the transmission circuit, the reception circuit, and the serial transmission path A test signal generation circuit that generates a test signal having a rate and outputs the test signal to the transmission circuit;
Detecting the phase of the rising or falling edge of the test signal received by the receiving circuit via the transmission circuit and the serial transmission line, and the phase of the rising or falling edge of the test signal and the phase of the reference clock A phase detection circuit that outputs the phase difference between the two as phase data;
A deterioration determination circuit that determines deterioration of the serial signal based on the phase data output from the phase detection circuit and outputs deterioration determination information;
A transmission / reception system having a function of determining deterioration of a communication path by a test signal. The transmission / reception system is a single device including the transmission circuit, the reception circuit, the phase detection circuit, the deterioration determination circuit, and the test signal generation circuit,
The serial transmission line is a transmission line that directly connects the transmission circuit and the reception circuit;
2. The transmission / reception system having a communication path deterioration determination function according to claim 1, wherein the deterioration determination circuit determines deterioration of the test signal transmitted from the transmission circuit and received by the reception circuit. . In the transmission / reception system, a first device including the transmission circuit and the test signal generation circuit, and a second device including the reception circuit, the phase detection circuit, and the deterioration determination circuit are connected by the serial transmission path. System,
The transmission / reception system having a function for determining deterioration of a communication path using a test signal according to claim 1, wherein the deterioration determination circuit determines deterioration of the test signal transmitted from the transmission signal and received by the reception circuit. .   4. The test signal according to claim 1, wherein the test signal is a signal having the highest or lowest mark rate that can be generated as a serial communication signal transmitted and received by the transmission / reception system. A transmission / reception system having a function of judging deterioration of a communication channel by a test signal.   The deterioration of the communication path due to the test signal according to claim 1, further comprising a switching unit that switches between transmission of the test signal and transmission of the signal for the serial communication by a switching signal. A transmission / reception system having a determination function.   The switching signal is generated for a predetermined time after power-on, a switching command received from the receiving circuit, a switching signal input from an external input signal receiving unit, a switching command input from a network-connected communication circuit, or the like. 6. The transmission / reception system having a communication path deterioration determination function based on a test signal according to claim 5, wherein   A deterioration determination information holding circuit for holding deterioration determination information output from the deterioration determination circuit, and deterioration of the transmission circuit, the reception circuit, and the transmission path based on a determination result held in the deterioration determination information holding circuit 7. A transmission / reception system having a communication path deterioration determination function using a test signal according to claim 1, further comprising display means for displaying a status.

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