JPH03240148A - System switching operation protecting circuit - Google Patents

Abstract

PURPOSE:To prevent the switch of systems due to a malfunction of a control part of a communication controller by providing a system switch information inspecting means which outputs a system actuation signal after inspecting a fact that the system switch information is obtained from combination of the prescribed information. CONSTITUTION:When the system switch conditions are satisfied while a communication controller 1a is serving as a spare system, a control part 4a receives a signal from a system switch condition setting part 5a to know that the system switch conditions are satisfied. Then a system switch information output means 6a outputs the system switch information consisting of combination of the prescribed information. A system switch information inspecting means 7a inspects a fact that the received information is identical with the normal system switch information and transmits a system actuation signal. A system switch executing means 8a switches the controller 1a of its own system to an operation system. Therefore an irregular signal is outputted from the part 4a and the normal system switch information is never transmitted even when the part 4a of the controller 1a of the spare system run away, etc. Thus it is possible to prevent the switch of systems which are caused by the malfunctions of the control parts 4a and 4b of the communication controllers 1a and 1b.

Description

[Detailed Description of the Invention] [Summary] Regarding the switching circuit between the active system and the standby system of a duplex communication control device, the purpose of this invention is to prevent switching of the system due to malfunction of the control section in the communication control device. Each of the duplex communication control devices connected to a plurality of communication devices and each connected to a communication line has a control unit that controls the communication control device, and a control unit that controls the communication control device within the communication control device. A system switching condition setting unit that exchanges information necessary for switching the communication control device to the active system or the standby system between each unit and the duplexed other system communication control device, and sets system switching conditions; system switching information output means for outputting system switching information consisting of a specific combination of information when receiving a signal from the system switching condition setting unit informing that a condition for switching the communication control device to an active system has been satisfied; system switching information verification means for receiving the system switching information from the system switching information outputting means and outputting a system activation signal when verifying that the system switching information is a specific combination of information; A system that switches its own system communication control device to an active system when receiving a system operation signal from an information verification means, and outputs a switching signal that switches another system communication control device to a standby system via the system switching condition setting section. and switching execution means, and is configured to prevent system switching due to malfunction of the control unit of the communication control device.

[Industrial application field]

The present invention relates to a switching circuit between an active system and a standby system of a duplex communication control device.

In recent years, when an information processing device communicates with a remote device,
2. Description of the Related Art Means for increasing reliability by duplicating communication control devices that control communications has come into widespread use.

Conventionally, such a communication control device has been used in a configuration in which a redundant central control device is connected to a channel control device and a common bus, and the communication system? Control of the IIQ system and system switching between the active system and the standby system were performed under the control of a central controller.

In the above configuration, even if a malfunction occurs in the central control unit and a system switching command is sent by mistake, switching control is left to the central control unit.
No measures have been taken to prevent switching on the communication control device side.

However, recently, systems have appeared in which a communication control device is directly connected to the user's communication device, and there are cases in which the redundant communication control device controls switching between the active system and the standby system by itself. It came out. In such a case, if the control unit of the standby system communication control device malfunctions, for example, goes out of control, the system switching register is activated to switch to the active system, and accordingly, the active system communication control device is switched to the standby system. A situation occurs that disconnects communication that was being performed normally.

In order to prevent such erroneous switching, there is a need for a communication control device that has a function to prevent system switching from occurring even if a malfunction occurs in the standby communication control device.

[Conventional technology]

FIG. 5 is a configuration diagram of the prior art, and FIG. 6 is a circuit block diagram of the prior art.

Conventionally, when using redundant communication control equipment, the fifth
It is common to have a configuration as shown in the figure.

That is, as shown in FIG.
C) 21a, 21b, channel control device (CHC)
24a, 24b, communication control devices 26a, 26b
Both of the communication lines 30a and 30b are duplexed, and the channel control devices 24a and 24b and the communication control device 26
A and 26b are connected by common buses 25a and 25b, respectively.

In the above system, for example, when the central control device 21a, channel control device 24a, common bus 25a, and communication control device 26a are communicating using the communication line 30a as an operating system, the communication control device 26a Line 3
If part of the system such as 0a is determined to be defective and the system is switched, the central control device 21a, channel control device 24b, common bus 25b, communication control device 26b and communication line 30b
becomes the operating system.

In this case, the switching control is performed by a system switching condition setting section 22a in the central control device 21a receiving system switching conditions from each section (not shown) in the central control device 21a, and when the system switching conditions are satisfied, the system switching condition setting section 22a The switching request sending unit 23a sends a system switching signal to the system switching register 27b of the communication control device 26b via the channel control device 24b and the common bus 25b,
The system switching register 27b that has received the system switching signal sends a signal to the system switching circuit 28b to switch the communication control device 26b to the active system. When the communication control device 26b is switched to the active system, the communication control device 26a is switched from the system switching circuit 28b to the active system.
An output signal is sent to the system switching circuit 28b to switch the communication control device 26a to the standby system.

FIG. 6 is an example of a circuit block diagram of a communication control device used in the configuration shown in FIG. 5, mainly showing the active system/standby system switching section. use the same symbol.

In FIG. 6, when the communication control device 26a is in the standby system, when a system switching signal is sent from the central control device and channel control device (CHCO, not shown) via the common bus 25a, the system switching occurs. The register 27a receives this and outputs an ACT pulse for switching the communication control device 26a to the active system to the system switching circuit 28a.

On the other hand, when the communication control device 26a is in the standby system, the L level is input to the R terminal of the system switching circuit 28a, so the H level is output from NANDzz and N A
It is input to NDz I-. Therefore, the AC
NAND until the T pulse is sent.

Since the two inputs of , are both at H level, the output is L.
The level becomes INV2. , an H level is output. L from the Q terminal of the system switching circuit 28a or 28b
The state where the level is being output, that is, the switching output terminal 32
A state in which H level is output from a indicates that the communication control device 26a or 26b that is outputting is a standby system, and an L level indicates that it is an active system, so the above state In this case, the communication control device 26a is a standby system.

In this state, when the above-mentioned ACT pulse is input to the S terminal of the system switching circuit 28a, the input section becomes L level at the fall of the pulse, so the output of NAND 21m becomes H level, and the input signal passes through INVz+-. L level is output,
The communication control device 26a is switched to the active system.

The communication control device 26a is switched to the operating system, and the output terminal 3
When the L level is output from 2a, the output is input to the terminal 33b of the communication control device 26b, but at this time, ○R2□
Looking at the signal level input to 1, the other system power-off detection circuit 31b is at L level because the communication control device 26a is powered on, and the signal level 15O is on when operating only in the own system.
Since L is off in the normal state, the L level, and therefore O
The input via Rz+b becomes L level, and L level is output from ORz□5. Further, if the communication control device 26b is powered on, the power-on reset signal is at H level, but since the signal from 0Rzzb is at L level, the output of A N D z Ib is at L level, and therefore the system The L level is manually applied to the R terminal of the switching circuit 28b. When an L level is manually applied to the R terminal of the system switching circuit 28b, an H level is output from the output terminal 32b as described above, indicating that the communication control device 26b has become a standby system.

Also, when the l5OL signal is sent from the central control unit (not shown) and the signal is at H level, or because the power of another system is off, the output of the other system power-off detection circuit 31a is at H level. When it is, H from ORz+-
Since the level is output and input to ○R2o, regardless of whether the communication control device 26b of the other system is the active system or the standby system, if the power of the own system is on, A N D z
The output of I- becomes H level and is input to the R terminal of the system switching circuit 28a. At this time, the output of N A N D z I- is at L level, so the output of N A N D zz - is at H level, but when the ACT pulse is output from the system switching register 27a, N A N.D.
The output of zl- becomes H level, and even after the ACT pulse ends, the outputs of NAND, □, maintain H level, and the L level indicating the operating system is sent from the switching output terminal 32a.

In the above, all switching of the communication control devices 26a, 26b to the operating system is left to the control of the central control devices 21a, 21b. For this reason, for example, if the control circuit (not shown) of the central control device 21a goes out of control and the system switching signal is sent to the system switching register 27b of the communication control device @26b, which is a standby system, the communication control device 26b Since the communication control device 26a is switched to the active system and the communication control device 26a is switched to the standby system, an abnormality will occur in communication. However, since the central control device 21a itself is in an abnormal state, it is meaningless to take measures to prevent such abnormal switching in the communication control devices 26a and 26b.

However, when a system appears in which a communication control device is directly connected to a user's communication device, it becomes necessary for the redundant communication control device to perform system switching control between the active system and the standby system by itself. At this time, if the system switching circuit as described above is used, if the control unit of the standby communication control device malfunctions, for example, goes out of control, it will operate the system switching register and switch to the active system, and accordingly the communication control of the active system will be controlled. The device would have to be switched to the standby system, which could lead to a situation where communications that were normally being performed would be cut off.

[Problems to be Solved by the Invention] In conventional communication control devices, system switching between the active system and the standby system was performed under the control of the central control device when using duplex systems. In systems where communication control equipment is directly connected, the duplex communication control equipment performs system switching control between the active system and the standby system by itself, so if the control unit of the standby system communication control unit malfunctions, system switching will occur. There is a possibility that the register is operated to switch to the active system, and the communication control device of the active system is accordingly switched to the standby system, leading to a situation in which communications that were normally being performed are cut off.

An object of the present invention is to prevent system switching due to malfunction of a control unit in a communication control device.

[Means to solve the problem]

FIG. 1 is a diagram explaining the principle of the present invention.

In the figure, 1a and 1b represent one or more communication devices 2a and 2n.
duplex communication control devices 4a, 4b to 8a, 8b connected to communication lines 3a, 3b, respectively;
are respective means provided in the communication control devices 1a and 1b, 4a and 4b are control units for controlling the communication control devices, and 5a and 5b are means for controlling the communication control devices in the communication control devices 1a and 1b. Communication control devices 1a, 1 between each part and the duplicated other system communication control devices 1b, 1a.
a system switching condition setting unit, 6a, which sends and receives information necessary for switching b to the active system or the standby system, and sets system switching conditions;
, 6b is the communication control device 1a or 1b from the system switching condition setting section 5a, 5b in the control section 4a, 4b.
System switching information output means 7a and 7b are system switching information output means 6a and 6b for outputting system switching information consisting of a specific combination of information when receiving a signal informing that a condition for switching to the active system has been satisfied. 8a and 8b are system switching information verification means for receiving the system switching information from the system switching information and outputting a system activation signal when verifying that the system switching information is a specific combination of information; When a system activation signal is received from 7a, 7b, the own system communication control device 1a or 1b is switched to the active system, and the other system communication control device 1b or 1 is switched via the system switching condition setting section 5a, 5b.
It is a system switching execution means that outputs a switching signal for switching a to a standby system, and is a system switching execution means that outputs a switching signal for switching a to a standby system, and is a system switching execution means that outputs a switching signal to switch a to a standby system, and is a system switching execution means that outputs a switching signal to switch a to a standby system.
The system is configured to prevent switching of the system due to malfunction of b.

[For production]

In FIG. 1, for example, when the communication control device 1a is in the standby system, the power of the communication control device 1b in another system, which was being used as the active system, is cut off, and the communication control device 1a is switched to the active system. When such a system switching condition is established, the control unit 4a uses the system switching condition setting unit 5a to select the communication control device 1a.
The system receives a signal indicating that the conditions for switching to the active system have been met, and starts the switching operation. As a specific system switching operation, first, the system switching information output means 6a outputs system switching information consisting of a combination of specific information. The system switching information includes, for example, a command and address information for accessing a specific area of a memory (not shown) in the communication control device 1a.

The system switching information outputted from the system switching information output means 6a is received by the system switching information verification means 7a, and when it is verified that the received information is regular system switching information, a system activation signal is sent to the system switching execution means 8a. Send out.

When the system switching execution means 8a receives the system activation signal, it performs an operation of switching its own system communication control device 1a to the active system, and also sends an output to the other system communication control device 1b via the system switching condition setting section 5a. Then, the other system communication control device 1b used as the active system is switched to the standby system (details not shown)
.

In the configuration shown in FIG. 1, for example, the standby communication control device 1
If the control unit 4a of the control unit 4a goes out of control, the signal output from the control unit 4a will be irregular, so the regular system switching information as described above will not be sent out, and therefore, the There is no need to switch the communication control device 1a from the standby system to the active system.

〔Example〕

FIG. 2 is a circuit block diagram of an embodiment of the present invention, FIG. 3 is an operation flow diagram of an embodiment of the present invention, and FIG. 4 is a timing chart of the embodiment of FIG.

Figure 2 shows a circuit block diagram of one system of the communication control device,
In the figure, 11 is a system switching information output unit in the control unit (CPU) in the communication control device, 12 is a successive verification circuit, 12a, 12
b is a component in the read verification circuit 12, 12a is a successive register, 12b is a pulse length conversion circuit, 13 is a write verification circuit, 13a is a write register in the write verification circuit 13,
14 is an ACT output circuit, 15 is a system switching condition designation circuit in which switching conditions are set, RI"" Rs is a resistor, C is a capacitor, AND, ~AND s is a logical product (AND) circuit, OR, ~OR , is a logical sum (OR) circuit, NANDI
~NAND is a negative logical product (NAND) circuit, INV
I ~ I NV3 Inverter, DV is driver, L
-LE that lights up to indicate that ACT is in operation
It is D.

In addition, 31 to S4 in FIG. 3 are the symbols of each step, and the second
In the figure, the points ``■'' to ``■'' indicate the timing of potential changes in FIG. 4.

Hereinafter, FIG. 2 will be explained using FIGS. 3 and 4 together.

Now, assuming that the communication control device shown in FIG. An L level appears on the ``system display'' terminal (the 1st system is an H level). When the power is turned on in this state, the power-on reset signal is initially at L level and changes to H level after some time, but while it is at L level, it is not connected to the L level of the 0 system/1 system display j terminal. Since both become L level, the L level is sent to AND via OR3.H level is always output from the Y terminal of the write register 13a to the other terminal of AND2, but the L level is output from OR8. When input, the output of BAND2, that is, the input of the S terminal of the ACT output circuit 14 becomes L level.

At this time, the L level of the 0 system/1 system display terminal is converted into potential by INV3 and inputted to one terminal of AND, and becomes H level, but the other terminal is inputted to the communication control device of the other system. If so, the L level is sent out via OR, so the AND.

Therefore, an L level is output to the R@ terminal of the ACT output circuit 14. Therefore, the output of the ACT output circuit 14ONAND2 becomes H level and is input to one terminal of N A N D l . Since the L level is manually applied to the other terminal of the NAND, that is, the S terminal, as described above, the NAND
The output of , that is, the Q terminal of the ACT output circuit becomes H level, and is converted to L level via INV. INV
The output of , is outputted from the ACT terminal via the driver DV, and as shown in the figure, the fact that the output level is L level indicates that the communication control device is an active system (ACT system). The output of INV also activates the LED L-ACT, indicating that the communication controller is in the ACT state.

The communication control device of the first system when the communication control device of the own system is set as the active system as described above will be explained with reference to FIG.

In the 1-system communication control device, the H level is set to the "O system/1 system display" terminal and the L level is input to OR4, but if the power is turned on, the power-on reset is at the H level. In Luno, an H level is output from ORa to AND. However, "before the L level from the 0 system is input to the other system ACTJ, the L level is input to OR2 via lNVt, and if there is no "other system power cut" or "crossing cable disconnection", the OR Since the L level is also input to the other terminals of , the L level is input to AND3, and therefore the L level is output from the AND. Therefore,
An H level is output to one terminal of the NAND terminal of the ACT output circuit. At this time, the H level from the write register and the H level of the power-on reset signal are input to AND, so the S terminal goes to H level, and both terminals of NANDI go to H level, so NA
The output of ND passes through L level, INV, and then H level is output, indicating that it is a standby system. After this, "L level is input to the other system ACTJ from the own system, and H level is output from AND, but since L level is input from NAND to one terminal of NAND z, The output of NAND becomes H level, and the output level from the Q terminal remains unchanged.

Next, the operation of switching the communication control device set as the standby system as described above to the active system will be explained.

In FIG. 2, when the CPU receives a condition for switching the communication control device to the active system (details are not shown), system switching information is sent from the system switching information output unit 11 in the CPU, but the system switching information is The content shown in the figure is assumed. That is, when the system switching condition, that is, the condition for converting the own system into an active system (referred to as ACT) is satisfied at Sl in FIG. 3, the system switching information output unit 11 first performs the first stage of system switching information output in S2. As a result, successive register accesses are made, for example, successive accesses are made to address I101000080 in the memory, and then write register accesses are made, for example, write accesses are made to address I101000090, as the second stage of system switching information output in S3. Since the purpose of these devices is not to read or write data, they do not read or write data. The above two-stage system switching information is accessed by the successive verification circuit 12 and write verification circuit 13 in FIG. ACT
The ACT output circuit 14 operates to switch the system to ACT (Fig. 3, 34).
However, the above operation will be explained in detail with reference to FIG.

First, from the system switching information output unit 11, PC3R and ARI~AR
3 is output, PC3R indicates chip selection information for selecting the successive register 12a, ARI to AR3 indicate the lower three digits of address information, and these four pieces of information indicate the specific I10.
You will have to specify the address. Next, pulses are output to l0RD, and when all of these pulses are input at the same time, an output is sent from the output terminal Y of the successive output register 12a.

The above timing relationship will be explained with reference to FIG. 4. The circuit shown in FIG. 2 is operated by a clock pulse (not shown), and an operating cycle is formed by four clock pulses as shown in FIG. 4.

Each pulse turns on or off at the first falling point of a clock pulse such as Tl or T2, but in Figure 4, the on and off points of each pulse are shown slightly later than the falling point of the clock pulse for ease of viewing. ing.

The PC3R is input to the successive register 12a by the TI of the first cycle of the clock pulse as shown in (2) in FIG. 4, but address information ARI to AR3 is also input at the same time (not shown in FIG. 4).

Next, the I ORD of ■ is input to T2, and when all of these are input and match the preset address, the output of ■ is sent from Y of the successive register 12a. The pulse (2) is input to the S terminal of the pulse length conversion circuit 12b, but the pulse length is extended due to the effect of the time constant circuit consisting of R1 and C connected to the R/C terminal, and the pulse (2) in FIG. It is sent out as a pulse like this.

The system switching information output unit 11 then proceeds to write register access, and at this time, the write register 13a becomes operational when an H level is input to the G terminal;
The conditions are that the own system OUS information is output from the system switching information output unit 11 of the U, and that the own system communication control device is in the standby system state. A state in which the own system OUS information is output (L level) indicates that the own system is abnormal, so it is inappropriate to switch to the active system, and switching to the active system is only possible when the own system is a standby system. This is because there is no meaning otherwise. If the own system is not abnormal and is a standby system, the own system is ○U.
Since the outputs of S information and INVI are both at H level, the output of AND is at H level and input to the G terminal of write register 13a, and write register 13a becomes operable.

When the system switching information output unit 11 moves to write register access in the above state, PC3W and AWI to AW of
3 (not shown in FIG. 4) and ■ rowc are output. When these pulses match a preset address and these and the outputs from Y to ■ of the successive register 12a are all input at L level, the write register 13
■ is output from the output terminal Y of a. The pulse of the ■ is A
This is a self-system ACT pulse that operates the CT output circuit 14.

An H level is always output from the output terminal Y of the write register 13a and input to the AND, but if the own power supply is input to the other terminals of the AND, an H level is output. Therefore, in this state, the output from the A N D z is at H level and is input to the S terminal of the ACT output circuit 14. In this state, when the self-system ACTing pulse (■) is input, one terminal of ANDt becomes L level, so L level is input to NAND, and NAND,
The output of the ACT output circuit 14, that is, the output (2) of the Q terminal of the ACT output circuit 14 becomes H level. The output is converted to L level by INV, and the communication control device is converted to ACT.
The "other system ACT" of the other system's communication control device is connected from the rACTJ terminal.
Outputs L level to the J terminal. Note that a description of the operation within the communication control device based on ACT will be omitted.

As explained above using the embodiment, in normal system switching, successive accesses and write accesses are performed successively in the steps shown in FIGS. 2 and 4, and the addresses of both accesses are correct and The ACT pulse (2) is not output unless the timing between successive access and write access is within the range limited by the output pulse (2) of the pulse length conversion circuit Q in FIG. Therefore, even if the CPU of the standby system communication control device goes out of control, there is no possibility that signals and information that meet the above conditions will be output from the CPU (system switching due to malfunction is prevented. be done.

Note that the above embodiment is merely an example, and it is clear that the effects of the present invention will not essentially change even if the use of successive access and write access, the order of the two accesses, the number of address digits, etc. are changed. However, the present invention does not exclude these modifications.

〔Effect of the invention〕

As explained above, according to the present invention, when the control section in the communication control device switches between the active system and the standby system in a duplex communication control device, switching of the system due to malfunction of the control section can be prevented. This greatly contributes to improving the reliability of such a communication control device.

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the present invention, FIG. 2 is a circuit block diagram of an embodiment of the present invention, FIG. 3 is an operation flow diagram of an embodiment of the present invention, FIG. 4 is a timing diagram of an embodiment of the present invention, and FIG. FIG. 5 is a configuration diagram of the prior art, and FIG. 6 is a circuit block diagram of the prior art. In the figure, 1a, 1b 2a, 2n 3a, 3b 4a, 4b 5a, 5b 6a, 6b 7a, 7b 8a, 8b. Communication control device Communication device Communication line control section System switching condition setting section System switching information output means --- System switching information verification means --- System switching execution means 3rd Figure diagram

Claims (1)

[Claims] Each of the duplex communication control devices (1a, 1b) connected to one or more communication devices (2a, 2n) and connected to the communication line (3a, 3b), A control unit (4a, 4b) that performs control within the control device (1a, 1b)
), and in the communication control device (1a, 1b), each part in the communication control device and the duplexed other system communication control device (1b, 1
a) a system switching condition setting unit (5a, 5b) that sends and receives information necessary for switching the communication control device (1a, 1b) to the active system or the standby system, and sets system switching conditions; In the control unit (4a, 4b), the communication control device (1a or 1
system switching information output means (6a, 6b) that outputs system switching information consisting of a specific combination of information when receiving a signal informing that a condition for switching b) to an active system is satisfied; system switching information verification means (7a, 7b) that receives the system switching information from the means (6a, 6b) and outputs a system activation signal when verifying that the system switching information is a specific combination of information; and the system switching information verification means (
When receiving a system activation signal from 7a, 7b), the own system communication control device (1a or 1b) is switched to the active system, and the other system communication control device is switched to the active system via the system switching condition setting section (5a, 5b). system switching execution means (8a, 8b) that outputs a switching signal for switching the communication control device (1a, 1b) to the standby system;
A system switching operation protection circuit characterized in that it prevents system switching due to the malfunction described in b).