JP2016091252A - IEEE1394 interface circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an IEEE 1394 interface circuit capable of inexpensively overcoming the problem with multiplexing without degrading reliability.SOLUTION: An IEEE 1394 interface circuit includes a user IF that relays an input/output signal with a peripheral apparatus; and a fault determination circuit that monitors a failure of a bus IF. The bus IF includes three or more input/output ports that can be connected to a redundant network. If two of the ports are connected to the redundant network and the failure determination circuit detects a failure of the bus IF, the interface circuit disconnects its own IEEE 1394 interface circuit including the bus IF from the redundant network.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an IEEE 1394 interface circuit equipped with an IEEE 1394 standard interface module.

A general-purpose, inexpensive, 3-port IEEE 1394 standard interface module (hereinafter abbreviated as an IF module) as an interface module that relays signals between an observation device and the data processing circuit that captures the data. Are sold to the market.

However, spacecrafts such as artificial satellites and observation satellites use the above-mentioned inexpensive commercial IF modules because of the special circumstances that they are used in environments where maintenance is not possible (including very difficult cases). I can't.
Therefore, an interface module having sufficient radiation resistance has been developed.
In order to further improve the reliability, the interface module is made redundant to improve the overall reliability.

  As such a redundancy technique, for example, in Japanese Patent Application Laid-Open No. 2006-215645, a fault transient computer system using a daisy chain connection method is disclosed.

  In the connection method shown in FIG. 3, six IF modules 100 to 106 are connected by wirings 121 to 127. The IF module 100 is a computer interface, and the IF modules 101 to 106 are interfaces of various measuring instruments. Consider a case where the measurement data of the IF module 101 to IF module 106 is taken into the computer via the IF module 100.

  In this case, for example, when the IF module 102 fails, the IF module 101 transmits / receives data to / from the IF module 100 via the wiring 121, and the IF modules 103 to 106 transmit / receive data to / from the IF module 100 via the wirings 124 to 127. I do. Therefore, even if the IF module 102 fails, the other IF modules 101 and 103 to 106 can transmit / receive data to / from the IF module 100.

  Next, consider a case where the IF module 102 and the IF module 105 fail. In this case, the IF module 101 can transmit / receive data to / from the IF module 100 via the wiring 121, and the IF module 106 can transmit / receive data to / from the IF module 100 via the wiring 127. However, even if the IF modules 103 and 104 between the IF module 102 and the IF module 105 are normal, data cannot be transmitted to and received from the IF module 100. That is, even if the IF modules 103 and 104 are normal, they are substantially the same as if they failed.

  Therefore, there is a method shown in FIG. 4 as a connection method for preventing such inconvenience. In FIG. 4, even if the IF module 102 and the IF module 105 fail, the IF module 103 can transmit and receive data to and from the IF module 100 via the wirings 132 and 121. In addition, the IF module 104 can transmit and receive data to and from the IF module 100 via the wires 133 and 127. Therefore, the IF module that has not failed can exchange data with the IF module 100.

JP 2006-215645 A

  However, an interface module with high radiation resistance is expensive, and double redundancy, triple redundancy, and the number of redundancy increases, the mass, power consumption, the number of parts, etc. increase due to the increase in the number of wires. Problem (hereinafter referred to as a multi-redundancy problem) occurs.

  Therefore, a main object of the present invention is to provide an IEEE 1394 interface circuit that can overcome the problem of multiple redundancy at low cost without reducing reliability.

  In order to solve the above-described problem, when a bus IF composed of IEEE 1394 standard modules is connected by a daisy chain system to form a redundant network, the IEEE 1394 relays signals between peripheral devices and the redundant network including the bus IF. The invention relating to the interface circuit includes a user IF that relays an input / output signal to / from a peripheral device, and a failure determination circuit that monitors a failure of the bus IF. The bus IF has an input / output port that can be connected to a redundant network. When three or more of them are connected to the redundant network and the failure determination circuit detects a failure of the bus IF, the IEEE 1394 interface circuit including the bus IF is disconnected from the redundant network. It is characterized by that.

  According to the present invention, even if a bus IF composed of an IEEE 1394 standard module is used, if a failure occurs due to self-diagnosis, it automatically leaves the redundant network. Can be overcome.

It is a block diagram of an IEEE1394 interface circuit. It is a block diagram when a redundant network is configured by daisy chaining IEEE 1394 interface circuits. It is a block diagram at the time of wiring duplication applied to description of related technology. It is a block diagram at the time of wiring triple applied to description of a related technology.

  An embodiment of the present invention will be described. FIG. 1 is a block diagram of an IEEE 1394 interface circuit (IF circuit) 2 according to the present embodiment.

  FIG. 2 is a block diagram when the three IF circuits 2 (2a to 2c) are connected to the IEEE 1394IF (hereinafter referred to as the main body IF) 3 of the main body (data processing side circuit) via the data bus Lb by the daisy chain method. is there. Each IF circuit 2 is connected to a peripheral device IF4 such as an observation device via a user IF10. All IF circuits 2 operate in synchronization with a synchronization signal (not shown). Hereinafter, a configuration in which a plurality of IF circuits 2 are wire-connected by a daisy chain method is appropriately described as a redundant network.

  As shown in FIG. 1, the IF circuit 2 includes a user IF 10, a bus IF 20, and a failure determination circuit 30. A master notification line Lm for transmitting master information is connected to the user IF 10. Further, the failure determination circuit 30 is connected to a state notification signal line Ls including an upstream state notification signal line Ls_U that transmits the upstream state notification signal G4 and a downstream state notification signal line Ls_D that transmits the downstream state notification signal G5. . Here, “upstream” and “downstream” are terms that allow the right side to be identified as the upstream side and the left side as the downstream side, since the IF circuit is present on the left and right with respect to the IF circuit illustrated in FIG.

  Although all IF circuits 2 have the same configuration, one IF circuit 2 has the authority (relay authority) to input / output data between the main body IF 3 and the peripheral device IF 4 via the data bus Lb. have. The IF circuit having the authority to relay is described as a master IF circuit, and the other IF circuits are described as a checker IF circuit.

  Hereinafter, for convenience of explanation, the IF circuit 2b is a master IF circuit, and the IF circuits 2a and 2c are checker IF circuits. At this time, the IF circuit 2a may be described as an upstream checker IF circuit, and the IF circuit 2c may be described as a downstream checker IF circuit. Further, the term “own IF circuit” may be used in the description of the circuit operation, which means that the IF circuit includes the bus IF or the like of interest.

  The failure determination circuit 30 is a circuit that determines whether or not the device itself has failed. This determination result is sent to the other IF circuit 2 via the state notification signal line Ls. At this time, if the device itself is the master IF circuit 2, the master information is output to the other IF circuit 2 via the master notification line Lm. For example, when the master IF circuit 2b fails, master information is output from the master IF circuit 2b to the upstream checker IF circuit 2a. The upstream checker IF circuit 2a that has received this master information becomes a new master IF circuit 2a, and the IF circuit 2b leaves the redundant network.

  Details will be described below. The user IF 10 is connected to the peripheral device IF 4 and relays the master notification line Lm.

  The bus IF 20 is composed of a consumer IEEE 1394 standard IF module having three ports 5a to 5c, and is connected to the data bus Lb. One of the three ports is not used, but the other ports are connected to the data bus Lb via connectors including connectors and wiring.

  The failure determination circuit 30 includes a diagnostic signal generation unit 31, a comparison circuit 32, a detection circuit 33, and a switch unit 34. The switch unit 34 includes an upstream switch 34a that relays the upstream state notification signal line Ls_U and a downstream switch 34b that relays the downstream state notification signal line Ls_D.

  The diagnostic signal generator 31 generates a predetermined diagnostic signal G1. The diagnostic signal G1 is output to the data bus Lb via the bus IF 20 and also output to the comparison circuit 32.

  The comparison circuit 32 receives the diagnostic signal G1 directly from the diagnostic signal generator 31, and also receives the diagnostic signal G1 output to the data bus Lb via the bus IF 20. The diagnostic signal G1 directly received from the diagnostic signal generator 31 is referred to as a direct diagnostic signal G1, and the diagnostic signal G1 received via the bus IF 20 is referred to as a diagnostic signal G2.

  The route diagnosis signal G2 is the diagnosis signal G1 input to the comparison circuit 32 via the bus IF 20 and the data bus Lb. Therefore, since the original signal is the same, the signal contents of the direct diagnosis signal G1 and the via diagnosis signal G2 should be the same. However, when a failure occurs in the bus IF 20, the data bus Lb, and the connector, the signal contents of the direct diagnostic signal G1 and the via diagnostic signal G2 are different.

  Therefore, failure diagnosis of the bus IF 20, the data bus Lb, etc. is performed by determining the identity of the direct diagnosis signal G1 and the route diagnosis signal G2. This determination result is output to the detection circuit 33 and the switch unit 34 as a diagnosis result signal G3.

  In addition to the bus IF 20, the data bus Lb and connectors are included as diagnostic targets for the following reason. That is, the connector is composed of connection terminals, wiring, and the like, and the important points are physically and electrically connected by solder or the like. Therefore, there are various failure points such as the terminal connection state, the terminal breakage state, the wiring disconnection, and the soldering point connection failure. However, it is difficult to specify the specific fault location, and even if it can be specified, there are many cases where it cannot be dealt with. Therefore, it is realistic to regard the bus IF 20, the connector, and the data bus Lb as repeaters. For this reason, the route diagnosis signal G3 input via the data bus Lb connected by the connector is used for the failure diagnosis of the bus IF 20.

  The detection circuit 33 receives the diagnosis result signal G3 from the comparison circuit 32, the upstream state notification signal G4 via the upstream state notification signal line Ls_U, and the downstream state notification signal via the downstream state notification signal line Ls_D. G5 inputs.

  Then, the detection circuit 33 determines whether or not its own IF circuit 2 is normal based on the diagnosis result signal G3 and the state notification signals G4 and G5. If it is determined by this determination that the own IF circuit 2 is not normal (failed), a failure signal G6 is output to the user IF 10.

  The user IF 10 is connected to the bus IF 10 via the data line Ld, and outputs data from the bus IF 10 to the peripheral device IF 4 and outputs data from the peripheral device IF 4 to the bus IF 10. The user IF 10 is connected to the user IF of the adjacent IF circuit via the master notification line Lm, and transmits / receives master information.

  The user IF 10 is connected to the detection circuit 33 and receives the failure signal G6 from the detection circuit 33. Upon receiving this failure signal G6, the user IF 10 recognizes that its own IF circuit 2 has failed, and outputs a disconnect signal G7 to the switch unit 34 and also outputs an output inhibition signal G9 to the bus IF 20. The disconnect signal G7 is a signal for executing its own IF circuit 2 to disconnect from the redundant network (detachment process), and the output prohibition signal G9 stops data input / output between the bus IF 20 and the data bus Lb. It is a signal to make.

  The upstream switch 34a and the downstream switch 34b receive the diagnosis result signal G3 from the comparison circuit 32 and the disconnection signal G7 from the user IF 10.

  When the upstream switch 34a and the downstream switch 34b receive the disconnect signal G7 from the user IF 10 (when the own IF circuit 2 is faulty), the upstream switch 34a and the downstream switch 34b receive signals from the adjacent IF circuit 2 input via the state notification signal line Ls. Status notification signals G4 and G5 are output as they are. In other words, the status notification signals G4 and G5 perform the leaving process for bypassing the IF circuit 2 of itself.

  On the other hand, when the own IF circuit 2 is normal, the upstream switch 34a and the downstream switch 34b output the diagnosis result signal G3 from the comparison circuit 32 to the state notification signal line Ls as the state notification signals G4 and G5.

  When the faulty own IF circuit 2 is disconnected from the redundant network, the energization of the own IF circuit 2 may be stopped or reduced. Thereby, useless power consumption can be reduced.

  By the way, when a failure occurs in the master IF circuit 2, the output prohibition signal G9 is output from the user IF 10 to the bus IF 20. As a result, the bus IF 20 is in an input / output prohibited state (withdrawal process).

  The user IF 10 outputs the output prohibition signal G9 and simultaneously outputs the master information G8 to the upstream IF circuit 2 via the master notification line Lm.

  At this time, the upstream IF circuit 2 receives the master information G8 via the master notification line Lm. Therefore, when the user IF 10 of the upstream IF circuit 2 receives the master information G8, the upstream IF circuit 2 receives the master information G8. The output inhibition signal G9 output to the bus IF 20 is stopped. Thereby, the bus IF 20 is permitted to input / output data to / from the data bus Lb, and the upstream IF circuit 2 is changed from the check IF circuit to the master IF circuit.

  Thus, when a failure occurs in the master IF circuit 2, the master IF circuit 2 is disconnected from the redundant network and the relay authority is transferred, so that the bus IF 20 has high reliability with respect to radiation or the like. Even if it is not designed, reliability can be maintained. In addition, an inexpensive IEEE 1394 standard IF module with 3 ports can be used, and the redundancy equivalent to a duplex configuration can be ensured to ensure the same reliability as a triple or more configuration, making the IEEE 1394 interface circuit inexpensive. Can be provided.

  In addition, since the number of redundancy can be reduced, the number of wires can be reduced, the weight can be reduced, and the number of parts can be reduced. Also, the power supply to the failed IEEE 1394 interface circuit can be stopped or reduced, so that the power consumption can be reduced. Become.

2 (2a to 2c) IEEE 1394 interface circuit (IF circuit)
3 Body IF
4 Peripheral device IF
5a-5c Port 10 User IF
20 Bus IF
30 Failure determination circuit 31 Diagnostic signal generation unit 32 Comparison circuit 33 Detection circuit 34 Switch unit 34a Upstream switch 34b Downstream switch

Claims (5)

An IEEE 1394 interface circuit that relays signals between peripheral devices and the redundant network, including the bus IF, when a bus IF composed of IEEE 1394 standard modules is connected by a daisy chain method to form a redundant network. ,
A user IF that relays input / output signals to and from the peripheral device;
A failure determination circuit for monitoring a failure of the bus IF,
The bus IF includes three or more input / output ports connectable to the redundant network, two of which are connected to the redundant network, and
When the failure determination circuit detects a failure of the bus IF, the IEEE 1394 interface circuit disconnects the IEEE 1394 interface circuit including the bus IF from the redundant network. An IEEE 1394 interface circuit according to claim 1, comprising:
An IEEE 1394 interface circuit that stops or reduces power supply to the IEEE 1394 interface circuit when the failure determination circuit performs the detachment process. An IEEE 1394 interface circuit according to claim 1 or 2,
The failure determination circuit includes:
A diagnostic signal generator for generating a diagnostic signal for use in diagnosing its own fault;
The diagnostic signal is received from the redundant network via the bus IF, and as a via diagnostic signal, the signal identity of the diagnostic signal and the via diagnostic signal is compared, and the comparison result is used as a diagnostic result signal. A comparator circuit to output,
When the diagnosis result signal indicates that the diagnosis signal and the route diagnosis signal are not the same, an output prohibition signal is output to the bus IF via the user IF, and the IEEE1394 of its own is output. An IEEE 1394 interface circuit, wherein the interface circuit is disconnected from the redundant network. An IEEE 1394 interface circuit according to claim 3, comprising:
The failure determination circuit includes:
A status notification signal line that is connected to the adjacent IEEE 1394 interface circuit and transmits a status notification signal indicating its own fault status;
A switch unit that relays the status notification signal line;
A detection circuit that receives the diagnosis result signal and the status notification signal, and outputs a failure signal to the user IF indicating that the IEEE 1394 interface circuit of the own device indicates a failure based on the diagnosis result signal and the status notification signal;
When the user IF does not receive the failure signal, the user IF transmits the status notification signal from the adjacent IEEE 1394 interface circuit to the adjacent IEEE 1394 interface circuit in the reverse direction through the status notification signal line, and When a failure signal is received, a disconnection signal for causing the switch unit to perform circuit switching for transmitting the diagnosis result signal to the adjacent IEEE 1394 interface circuit as the state notification signal on the state notification signal line is output. IEEE 1394 interface circuit characterized by the above. An IEEE 1394 interface circuit according to claim 4, comprising:
Of the plurality of IEEE1394 interface circuits, a master notification line is connected to the user IF to transmit master information indicating a relay authority capable of inputting and outputting data between the peripheral device and the redundant network. When determining that the IEEE 1394 interface circuit is faulty, the master information is output via the master notification line.

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