Optical module and control device

Abstract

To provide an optical module and a control device that can adjust signal gain.SOLUTION: An optical module according to an embodiment includes a photoelectric element and a gain adjustment unit. The photoelectric element performs at least one of converting an electrical signal into an optical signal and converting an optical signal into an electrical signal. The gain adjustment unit adjusts the gain of the signal level of at least one of the electrical signal and the optical signal output from the photoelectric element in testing the optical module.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment according to the present invention relates to an optical module and a control device. [Background technology]

[0002] Controller products such as control devices have long maintenance periods, so the parts they use often reach the end of their lifespan and need to be replaced. Furthermore, the operating environment and other factors can cause the product's characteristics to deteriorate earlier than expected. Continuing to use the product without noticing that its characteristics have deteriorated can lead to unintended operating conditions and unexpected malfunctions.

[0003] For example, optical modules with a shorter lifespan than the controller product may be used as connection modules. The output power of optical modules decreases over time. As a guideline for replacing optical modules, output power is measured after, for example, 10 years. Power measurement requires the preparation of a dedicated measuring instrument and the reconfiguration of the system, which requires a lot of maintenance work. It is desirable to be able to diagnose the degradation of optical module characteristics with less effort. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-37811 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide an optical module and a control device that can adjust the gain of a signal. [Means for solving the problem]

[0006] The optical module according to this embodiment includes a photoelectric element and a gain adjustment unit. The photoelectric element performs at least one of conversion from an electrical signal to an optical signal and conversion from the optical signal to an electrical signal. The gain adjustment unit adjusts the gain of the signal level of at least one of the electrical signal and the optical signal output from the photoelectric element during testing of the optical module. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a block diagram showing an example of the configuration of a control system and an operating device according to a first embodiment. [Figure 2] 1 is a block diagram showing an example of the configuration of an optical communication module according to a first embodiment. [Figure 3] 1 is a block diagram showing an example of the configuration of an optical module according to a first embodiment. [Figure 4A] FIG. 2 is a diagram illustrating an example of connection of the optical communication module according to the first embodiment. [Figure 4B] FIG. 2 is a diagram illustrating an example of connection of the optical communication module according to the first embodiment. [Figure 5] FIG. 4 is a block diagram showing an example of the results of a degradation diagnostic test on the optical module according to the first embodiment. [Figure 6] FIG. 3 is a flowchart showing an example of a degradation diagnostic test method for an optical module according to the first embodiment. [Figure 7] FIG. 10 is a diagram illustrating an example of connection of an optical communication module according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiment. The drawings are schematic or conceptual, and the proportions of the various parts are not necessarily the same as those in reality. In the specification and drawings, elements similar to those described above with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0009] (First embodiment) FIG. 1 is a block diagram showing an example of the configuration of a control system 1 and an operating device 2 according to the first embodiment.

[0010] The control system 1 includes a plurality of control devices. In the following, a case will be described in which the control system 1 includes three control devices 10, 20, and 30. However, as will be explained later, the number of control devices may be at least two or more.

[0011] The control devices 10, 20, and 30 are connected in a loop.

[0012] The operation device 2 receives input from a user so as to be able to operate the control system 1. The operation device 2 is, for example, a PC (Personal Computer) in which programs (tools) required for operating the control system 1 are installed.

[0013] Next, the internal configuration of the control device 10 will be described.

[0014] The control device 10 includes a control unit 11, an optical communication module 12, and a power supply 13.

[0015] The control unit 11 controls a device (not shown) to be controlled.

[0016] The optical communication module 12 connects and communicates between the control device 10 and other control devices 20 and 30. Details of the optical communication module 12 will be described later with reference to FIG.

[0017] The power supply 13 supplies power to the control unit 11 and the optical communication module 12 .

[0018] Next, the internal configurations of the control device 20 and the control device 30 will be described.

[0019] The control device 20 includes a control unit 21, an optical communication module 22, and a power supply 23. The control device 30 includes a control unit 31, an optical communication module 32, and a power supply 33.

[0020] The configuration of control units 21 and 31 is almost the same as the configuration of control unit 11, and therefore a detailed description thereof will be omitted. The configuration of optical communications modules 22 and 32 is almost the same as the configuration of optical communications module 12, and therefore a detailed description thereof will be omitted. The configuration of power supplies 23 and 33 is almost the same as the configuration of power supply 13, and therefore a detailed description thereof will be omitted.

[0021] Next, the configuration of the optical communication modules 12, 22, and 32 will be described.

[0022] 2 is a block diagram showing an example of the configuration of the optical communications modules 12 and 22 according to the first embodiment. Note that the optical communications module 32 is omitted from FIG.

[0023] The optical communication module 12 includes a communication unit 121, an optical module 122, a power adjustment unit 123, a determination unit 124, a display control unit 125, and a display unit 126. The communication unit 121 and the power adjustment unit 123 are provided in an optical communication control circuit.

[0024] The communication unit 121 transmits an electrical signal to the optical module 122 or receives an electrical signal from the optical module 122 .

[0025] The optical module 122 converts electrical signals into optical signals, or converts electrical signals into optical signals. That is, optical signals are used to transmit signals between the optical communication module 12 and the optical communication module 22. Optical signals have lower noise than electrical signals, and are therefore used in long-distance communications.

[0026] The configuration of the optical module 122 will be described in detail later with reference to FIG.

[0027] The power adjuster (adjustment information generator) 123 generates an adjustment code and outputs it to the optical module 122. The power adjuster 123 generates the adjustment code in a degradation diagnostic test (deterioration test mode) of the optical module 122. Note that the power adjuster 123 does not generate an adjustment code in the normal operation mode.

[0028] The deterioration diagnostic test for the optical module by gain adjustment using the adjustment code will be described later with reference to FIG.

[0029] The determination unit 124 determines the state (communication state) of the optical modules 122, 222 based on the signal level of the electrical signal output via the optical modules 122, 222, i.e., the electrical signal input to the communication unit 121. The determination unit 124 determines whether the optical modules 122, 222 are in a communication-enabled state. More specifically, the determination unit 124 determines the state of the optical modules 122, 222 based on a comparison between the signal level of the electrical signal output via the optical modules 122, 222 and a predetermined signal level.

[0030] In the degradation test mode, the determination unit 124, which operates in the same manner as in the normal operation mode, determines the communication state. That is, in a degradation diagnostic test of the optical module 122, the determination unit 124 determines the state of the optical module based on the signal level of the electrical signal output via the optical module 122, 222 to which an adjustment code has been input.

[0031] The display control unit 125 causes the display unit 126 to display the determination result of the determination unit .

[0032] The display unit 126 displays the determination result of the determination unit 124, i.e., the connection status of the optical modules 122 and 222. The display unit 126 is, for example, an LED (Light Emitting Diode). For example, the LED lights up when communication of the optical module 122 is normal, and turns off when communication of the optical module 122 is not normal.

[0033] The display on the display unit 126 will be described in detail later with reference to FIGS. 4A and 4B.

[0034] The optical communication module 22 includes a communication unit 221, an optical module 222, a power adjustment unit 223, a determination unit 224, a display control unit 225, and a display unit 226. The communication unit 221 and the power adjustment unit 223 are provided in the optical communication control circuit. As described above, the configuration of the optical communication module 22 is substantially the same as the configuration of the optical communication module 12.

[0035] The optical communication modules 12 and 22 operate in a transmit (TX) mode and a receive (RX) mode. When the optical communication module 12 operates in the transmit mode, the optical communication module 22 operates in the receive mode. When the optical communication module 12 operates in the receive mode, the optical communication module 22 operates in the transmit mode. In the optical communication module 12 in the transmit mode, the communication unit 121 transmits an electrical signal to the optical module 122, and the optical module 122 transmits an optical signal to the optical module 222. In the optical communication module 22 in the receive mode, the optical module 222 receives an optical signal from the optical module 122, and the communication unit 221 receives an electrical signal from the optical module 222.

[0036] Next, the configuration of the optical module will be described in detail using the optical module 122 as an example.

[0037] FIG. 3 is a block diagram showing an example of the configuration of the optical module 122 according to the first embodiment.

[0038] The optical module 122 performs signal conversion between an optical interface OI and an electrical interface EI. The optical interface OI is, for example, an optical fiber. In the example of the optical module 122 shown in Fig. 3, the left-right positional relationship between the optical interface OI and the electrical interface EI is reversed compared to the optical module 122 shown in Fig. 2.

[0039] The optical module 122 includes a receiving unit R, a transmitting unit T, and a gain control unit 1221.

[0040] The receiving unit R receives an optical signal from the optical interface OI, converts the optical signal into an electrical signal, and transmits it to the electrical interface EI. The receiving unit R has a light receiving element R1 and an amplifier R2.

[0041] The light receiving element R1 converts an optical signal into an electrical signal and is, for example, a photodiode.

[0042] The amplifier R2 amplifies the signal level of the electrical signal that is converted from the optical signal and output from the light receiving element R1.

[0043] The transmitter T receives an electrical signal from the electrical interface EI, converts the electrical signal into an optical signal, and transmits it to the optical interface O1. The transmitter T has a light emitting element T1 and an amplifier T2.

[0044] The light emitting element T1 converts an electrical signal into an optical signal and is, for example, a semiconductor laser or a light emitting diode.

[0045] The amplifier T2 amplifies the signal level of the electrical signal input to the light-emitting element T1 so that the electrical signal is converted into an optical signal. The signal level of the optical signal changes depending on the signal level of the electrical signal. Therefore, the amplifier T2 can change the signal level of the optical signal output from the light-emitting element T1 by changing the signal level of the electrical signal input to the light-emitting element T1.

[0046] The light receiving element R1 and the light emitting element T1 may be collectively referred to as a photoelectric element.

[0047] The gain control section 1221 controls the gains of the amplifiers R2 and T2. The gain control section 1221 may include a storage section that stores information necessary for controlling the gains of the amplifiers R2 and T2.

[0048] The receiving unit R, the transmitting unit T, and the gain control unit 1221 may also be referred to as a gain adjustment unit G. The gain adjustment unit G adjusts the gain of the signal level of at least one of the electrical signal and the optical signal output from the photoelectric element during a degradation diagnostic test of the optical module 122.

[0049] The gain adjustment unit G acquires an adjustment code relating to the amount of gain adjustment. More specifically, the gain control unit 1221 acquires an adjustment code (gain adjustment information) that can adjust the gains of the amplifiers R2 and T2 in the deterioration diagnostic test of the optical module 122.

[0050] The gain adjustment unit G adjusts the gain of the signal level of at least one of the electrical signal and the optical signal output from the photoelectric element based on an adjustment code related to the gain adjustment amount of the gain adjustment unit G. More specifically, the gain control unit 1221 controls the gain of the amplifiers R2 and T2 based on the adjustment code in a degradation diagnostic test of the optical module 122.

[0051] The gain adjustment unit G reduces the gain of at least one of the signal levels of the electrical signal and the optical signal output from the photoelectric element during testing of the optical module 122. The adjustment code is information for reducing the gain of the amplifiers R2 and T2. This allows the gain adjustment unit G (gain control unit 1221) to put the optical module 122 into a pseudo-degraded state.

[0052] The degradation diagnostic test is performed by the determining units 124 and 224 determining the communication state using the optical modules 122 and 222 that are artificially placed in a degraded state.

[0053] Next, a display example of the display unit 126 and a connection example of the optical communication modules 12, 22, and 32 will be described.

[0054] 4A and 4B are diagrams showing an example of the connection of the optical communication modules 12, 22, and 32 according to the first embodiment.

[0055] 4A and 4B show an example in which three optical communication modules 12, 22, and 32 are connected in a loop as shown in FIG.

[0056] Fig. 4A shows a case where communication between the optical communications module 12 and the optical communications module 22 is normal. Fig. 4B shows a case where communication between the optical communications module 12 and the optical communications module 22 is abnormal, i.e., where a communication error has occurred.

[0057] The optical communications module 12 (Module 1) has two optical modules 122a (CN1) and 122b (CN2) and two display units 126a (Link 1) and 126b (Link 2). The optical communications module 22 (Module 2) has two optical modules 222a (CN1) and 222b (CN2) and two display units 226a (Link 1) and 226b (Link 2). The optical communications module 32 (Module 3) has two optical modules 322a (CN1) and 322b (CN2) and two display units 326a (Link 1) and 326b (Link 2).

[0058] Furthermore, the optical communications modules 12 and 22 are connected by a cable C1. The optical communications modules 22 and 32 are connected by a cable C2. The optical communications modules 32 and 12 are connected by a cable C3. The cables C1, C2, and C3 are, for example, optical fiber cables.

[0059] The cable C1 connects the optical module 122a and the optical module 222b, the cable C2 connects the optical module 222a and the optical module 322b, and the cable C3 connects the optical module 322a and the optical module 122b.

[0060] The display units 126a and 126b display the communication states of the optical modules 122a and 122b, respectively. The display units 226a and 226b display the communication states of the optical modules 222a and 222b, respectively. The display units 326a and 326b display the communication states of the optical modules 322a and 322b, respectively.

[0061] In the example shown in FIG. 4A, as described above, communication between the optical communication module 12 and the optical communication module 22 is normal. The electrical signal output from the optical module 122a is equal to or higher than a predetermined signal level. The LED of the display unit 126a is lit, for example, in green. Similarly, the electrical signal output from the optical module 222b is equal to or higher than a predetermined signal level. The LED of the display unit 226b is lit, for example, in green.

[0062] In the example shown in FIG. 4B, as described above, communication between the optical communication module 12 and the optical communication module 22 is in an abnormal state. The electrical signal output from the optical module 122a is below a predetermined signal level. The LED of the display unit 126a is turned off. Similarly, the electrical signal output from the optical module 222b is below a predetermined signal level. The LED of the display unit 226b is turned off.

[0063] Next, a method for performing a deterioration diagnostic test on the optical modules 122 and 222 by gain adjustment using an adjustment code will be described.

[0064] The degradation diagnostic test is performed by switching from the normal operation mode to the degradation test mode on software using, for example, the operation device 2 shown in Fig. 1, as will be described later with reference to Fig. 6. In the degradation test mode, an adjustment code generated by the power adjustment unit 123 shown in Fig. 2 is used. Note that switching between the normal operation mode and the degradation test mode does not involve switching the cable connections or attaching another device.

[0065] Fig. 5 is a block diagram showing an example of the results of a degradation diagnostic test on the optical modules 122 and 222 according to the first embodiment. Fig. 5 shows an example in which the optical communications module 12 is in the transmission (TX) mode and the optical communications module 22 is in the reception (RX) mode. Fig. 5 shows the determination results under each of conditions 1 to 4.

[0066] 5, the default signal level of the communication unit 121 is −4 dBm. If the signal level of the electrical signal output from the optical module 222 (the electrical signal input to the communication unit 221) is −8 dBm or less, the determination unit 224 determines that the communication state is abnormal.

[0067] 5 indicates an adjustment code related to the amount of adjustment of the signal level. The state of the optical modules 122 and 222 is determined based on the signal level of the electrical signal output via the optical module (at least one of the optical modules 122 and 123) to which the adjustment code is input.

[0068] Under condition 1, the optical modules 122 and 222 have not yet deteriorated much, and no gain adjustment has been performed.

[0069] Under condition 1, the deterioration amount of the optical module 122 is 0 dB and the adjustment amount of the optical module 122 is 0 dB. Therefore, the optical module 122 outputs an optical signal of -4 dBm. Under condition 1, the deterioration amount of the optical module 222 is 0 dB and the adjustment amount of the optical module 222 is 0 dB. Therefore, the optical module 222 outputs an electrical signal of -4 dBm.

[0070] In condition 1, the determination unit 224 determines that the communication state of the optical module 222 is normal because the signal level of the electrical signal output from the optical module 222, −4 dBm, is higher than the predetermined signal level (for example, −8 dBm). Therefore, the display unit 226b lights up as shown in FIG. 4A.

[0071] Under condition 2, the optical module 122 is more deteriorated than under condition 1. In addition, no gain adjustment is performed.

[0072] Under condition 2, the deterioration amount of the optical module 122 is 3 dB and the adjustment amount of the optical module 122 is 0 dB. Therefore, the optical module 122 outputs an optical signal of -7 dBm. Under condition 2, the deterioration amount of the optical module 222 is 0 dB and the adjustment amount of the optical module 222 is 0 dB. Therefore, the optical module 222 outputs an electrical signal of -7 dBm.

[0073] In condition 2, the determination unit 224 determines that the communication state of the optical module 222 is normal because the signal level of the electrical signal output from the optical module 222, −7 dBm, is higher than the predetermined signal level (for example, −8 dBm). Therefore, as shown in FIG. 4A, the display unit 226b lights up.

[0074] In condition 3, compared to condition 2, the gain of the optical module 122 is adjusted.

[0075] Under condition 3, the deterioration amount of the optical module 122 is 3 dB, and the adjustment amount of the optical module 122 is -1 dB. Therefore, the optical module 122 outputs an optical signal of -8 dBm. Under condition 3, the deterioration amount of the optical module 222 is 0 dB, and the adjustment amount of the optical module 222 is 0 dB. Therefore, the optical module 222 outputs an electrical signal of -8 dBm.

[0076] In condition 3, the determination unit 224 determines that the communication state of the optical module 222 is abnormal because the signal level of −8 dBm of the electrical signal output from the optical module 222 is the same as the predetermined signal level (for example, −8 dBm). Therefore, as shown in FIG. 4B, the display unit 226b is turned off.

[0077] In condition 4, compared to condition 2, the gain of the optical module 222 is adjusted.

[0078] Under condition 4, the deterioration amount of the optical module 122 is 3 dB and the adjustment amount of the optical module 122 is 0 dB. Therefore, the optical module 122 outputs an optical signal of -7 dBm. Under condition 4, the deterioration amount of the optical module 222 is 0 dB and the adjustment amount of the optical module 222 is -1 dB. Therefore, the optical module 222 outputs an electrical signal of -8 dBm.

[0079] In condition 4, the determination unit 224 determines that the communication state of the optical module 222 is abnormal because the signal level of −8 dBm of the electrical signal output from the optical module 222 is the same as the predetermined signal level (for example, −8 dBm). Therefore, as shown in FIG. 4B, the display unit 226b is turned off.

[0080] Comparing Condition 3 with Condition 4, the gain adjustment of either the optical module 122 or 222 may be performed.

[0081] Comparing condition 2 with conditions 3 and 4, the total degradation of the optical modules 122 and 222 is increased from 3 dB to a pseudo 4 dB by gain adjustment. If the total degradation of the optical modules 122 and 222 increases by another 1 dB from the state shown in condition 2, the actual optical modules 122 and 222 will no longer be able to communicate. For example, if there is a possibility that the total degradation of the optical modules 122 and 222 will increase by 1 dBm or more before the next degradation diagnostic test, the optical modules 122 and 222 will need to be replaced.

[0082] The power adjusters 123, 223 generate an adjustment code relating to the amount of adjustment (gain adjustment amount) according to the time interval of the degradation diagnostic test. For example, if the time interval of the degradation diagnostic test is two years and the output of the optical module 122, 222 does not decrease by 1 dB or more in two years, the power adjusters 123, 223 generate an adjustment code with an adjustment amount of -1 dB. As a result, the optical module 122, 222 determined to be normal in the degradation diagnostic test is compensated for a two-year operating period margin.

[0083] Next, the flow of the optical module degradation test mode will be described.

[0084] FIG. 6 is a flowchart showing an example of a degradation diagnostic test method for an optical module according to the first embodiment.

[0085] In the operation device 2, a program for the optical module degradation test mode is added in advance to the program (tool) of the control system 1 required for the normal operation mode. The optical modules 122, 222, 322, etc. used in the control system 1 are registered in advance in the tool of the control system 1. The user switches modes by, for example, operating the operation device 2 and selecting the degradation test mode from the tool of the control system 1.

[0086] First, the operation device 2 acquires the optical communications modules to be used and the number of optical modules from the setting information of the tool (S10). In the example shown in FIGS. 4A and 4B, the number of optical communications modules 12, 22, and 32 in use is three. The operation device 2 calculates the number of optical modules that need to be diagnosed from the number of optical communications modules in use. Because two optical modules are installed in one optical communications module, the number of optical modules to be diagnosed, 122a, 122b, 222a, 222b, 322a, and 322b, is six.

[0087] Next, the operation device 2 acquires connection information of each optical communication module from the setting information of the tool (S20). The connection information includes information on the connection source and destination optical communication modules. In the example shown in FIGS. 4A and 4B, the optical module 122a is connected to the optical module 222b (diagnosis 1). The optical module 122b is connected to the optical module 322a (diagnosis 2). The optical module 222a is connected to the optical module 322b (diagnosis 3). The optical module 222b is connected to the optical module 122a (diagnosis 4). The optical module 322a is connected to the optical module 122b (diagnosis 5). The optical module 322b is connected to the optical module 222a (diagnosis 6).

[0088] Next, the communication unit, power adjustment unit, and determination unit adjust the output power of the transmitting side for each of the connection information items of Diagnosis 1 to 6 and perform a diagnosis (S30). In Diagnosis 1, the source optical module 122a is set to transmission (TX) mode, and the destination optical module 222b is set to reception (RX) mode. The power adjustment unit on the transmitting side generates an adjustment code to adjust the output power of the optical module 122a. The communication units on the transmitting and receiving sides communicate with the output power adjusted. The determination unit on the receiving side determines the communication state of the optical module 222b. If the communication state is determined to be normal, the operation device 2 records the diagnosis result of the optical module 222b as normal in a log. If the communication state is determined to be abnormal, the operation device 2 records the diagnosis result of the optical module 222b as abnormal in a log.

[0089] Tests 2 to 6 are performed in the same way as test 1. Note that test 4 reverses the relationship between the transmission mode and the reception mode in test 1. That is, in test 4, the source optical module 222b is set to the transmission mode, and the destination optical module 122a is set to the reception mode.

[0090] In step S30, the output power on the receiving side may be adjusted as shown in condition 4 in FIG.

[0091] Next, the operation device 2 displays the diagnostic results of each optical module on the screen of the tool (S40), thereby completing the degradation diagnostic test.

[0092] As described above, according to the first embodiment, the optical module includes a gain adjustment unit G that adjusts the gain of the signal level of at least one of the electrical signal and the optical signal output from the photoelectric element (at least one of the light receiving element R1 and the light emitting element T1) in a degradation diagnostic test of the optical module. This allows signal gain adjustment to be performed in the degradation diagnostic test.

[0093] Furthermore, in the degradation test mode, the power adjustment unit generates an adjustment code related to the gain adjustment amount of the gain adjustment unit G. The judgment unit judges the communication state of the optical module based on the signal level of the electrical signal output through the optical module. By incorporating an input / output power control function as a diagnostic function for the optical module, it is possible to put the optical module into a pseudo (virtual) state of characteristic degradation. As a result, it is possible to diagnose the characteristic degradation of the optical module and determine whether or not to replace the optical module.

[0094] The power adjustment unit generates an adjustment code to be input to the optical module while the optical module is connected to another control device. That is, the degradation test mode is performed with the same connection configuration as the normal operation mode.

[0095] In the first embodiment, the control system 1 includes three control devices. However, the control system 1 may include two control devices, or may include four or more control devices. Four or more control devices are connected in a loop, similar to the example shown in FIGS. 4A and 4B. The degradation diagnosis test is performed on all connections between two optical communication modules.

[0096] Next, a comparative example in which a degradation diagnostic test is performed using the optical power meter 3 will be described.

[0097] FIG. 7 is a diagram illustrating an example of a configuration according to a comparative example.

[0098] The optical power meter 3 is connected to the optical module 122a via a cable C4 and measures the output power of the optical module 122a. Whether or not to replace the optical module 122a is determined based on the measurement result of the optical power meter 3. For example, a determination of the result of the degradation diagnostic test is made based on a comparison between the measurement result and a value with a margin for the power that causes a communication abnormality.

[0099] However, when the optical power meter 3 is connected, the cables C1 and C4 connected to the optical module 122 must be connected and disconnected when performing a degradation diagnostic test. This increases the time required for connecting and disconnecting cables and may lead to configuration change errors. It is also necessary to prepare a dedicated measuring instrument for the degradation diagnostic test. Furthermore, if an abnormality is determined in the degradation diagnostic test, it is difficult to determine when the characteristics began to deteriorate. For example, if the optical module 122 is determined to be abnormal, even if communication is possible, the timing of past characteristic deterioration may become an issue.

[0100] In contrast, in the first embodiment, the degradation of the optical module 122 can be diagnosed by switching modes with the same configuration as in the normal operation mode. The mode switching is performed, for example, using the operation device 2. This reduces the effort required to change the configuration of the cables C1 and C4 and other measuring instruments for a degradation diagnostic test. Furthermore, if the operating period margin can be known, it is possible to plan replacement of the optical module 122 so that the optical module 122 can be operated within the operating period margin, where the possibility of characteristic degradation is low.

[0101] (Second embodiment) In the second embodiment, the adjustment code generated by the power adjustment unit 123 is different from that in the first embodiment.

[0102] The power adjuster 123 generates a plurality of adjustment codes with different adjustment amounts for one optical module 122. The gain adjuster G adjusts the gain of the signal level by sweeping it, for example, until the determiner 124 determines that the communication state is abnormal. This makes it possible to check the operating output margin of the optical module 122.

[0103] As in the second embodiment, it is possible to change the adjustment code generated by the power adjustment unit 123. The optical modules 122, 222, 322 and the control devices 10, 20, 30 according to the second embodiment can obtain the same effects as those of the first embodiment.

[0104] At least a part of the degradation diagnostic test method for optical modules according to this embodiment may be configured with hardware or software. In the case of a software configuration, a program realizing at least a part of the functions of the degradation diagnostic test method may be stored on a recording medium such as a flexible disk or a CD-ROM and read and executed by a computer. The recording medium is not limited to removable recording media such as magnetic disks or optical disks, but may also be fixed recording media such as hard disk drives or memories. In addition, a program realizing at least a part of the functions of the degradation diagnostic test method may be distributed via a communication line (including wireless communication) such as the Internet. Furthermore, the program may be encrypted, modulated, or compressed and distributed via a wired or wireless line such as the Internet, or stored on a recording medium.

[0105] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0106] 1 control system, 10 control device, 12 optical communication module, 122 optical module, 1221 gain control section, 123 power adjustment section, 124 judgment section, 125 display control section, 126 display section, C1 cable, C2 cable, C3 cable, R receiver section, R2 amplifier, T transmitter section, T2 amplifier

Claims

1. An optical module having: a photoelectric element that performs at least one of converting an electrical signal to an optical signal and converting an optical signal to an electrical signal; an amplifier that amplifies the signal level of at least one of an electrical signal that is input to the photoelectric element to be converted into an optical signal and an electrical signal that is converted from an optical signal and output from the photoelectric element; an amplifier control unit that controls the gain of the amplifier; and a gain adjustment unit that adjusts the gain of the amplifier for at least one of the electrical signal and optical signal output from the photoelectric element during testing; an adjustment information generating unit that generates gain adjustment information related to a gain adjustment amount of the gain adjusting unit; a determination unit that determines a state of the optical module based on a signal level of an electrical signal output through the optical module; Equipped with The control device, wherein the adjustment information generating unit generates the gain adjustment information regarding the gain adjustment amount according to a time interval of the test.

2. The control device according to claim 1 , wherein the adjustment information generator generates the gain adjustment information to be input to the optical module in a state where the optical module is connected to an optical module of another control device.

3. 3. The control device according to claim 1, wherein the determining unit determines the state of the optical module based on a comparison between a signal level of the electrical signal output via the optical module and a predetermined signal level.

4. The control device according to claim 1 , further comprising a display control unit that causes a determination result of the determination unit to be displayed on a display unit.

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