JP3035949B2 - Switching control method of master device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching control method of a master device that constructs a loop network.

[Conventional technology]

Conventionally, this type of master device switching control method is a method of arbitrating two master devices (an active device and a standby device).

This will be described with reference to FIG. FIG. 8 is a block diagram showing an example of the prior art.

In FIG. 8, the active master device 81 and the spare master device 8
2 and the slave devices 83 and 84 connect the working loop 85 and the backup loop 86 in series in the reverse direction, respectively, to form a loop network, and execute data transfer between the devices.

There is one master device in a loop forming one transmission path, and controls transmission in a loop network. The master device may be used in a regular / spare manner, but the alternate use of the current / spare will be described as an example. The loop also has working / spare like the master device, and is duplicated.

The active master device 81 transmits a code 00 indicating that the master device 81 is active, and a standby master device 82 transmits a code 01 indicating that the master device 81 is standby to predetermined positions of both the active / standby loops 85 and 86. Therefore, the active master 81 receives the code 01 and the spare master device 82 receives the code 00 to confirm normality.

When the active master device 81 switches the standby master device 82 to active due to a failure, the active master device transmits code 11 and the standby master device 82 transmits code 10 to confirm the switching.

The active master device monitors the active loop, and switches to the standby loop when a failure occurs in the active loop.

Further, when the working / spare loop is completely duplicated, the master device monitors the loop, and when it finds a fault in the loop, disconnects the fault location and forms the working loop and the protection loop into one loop. To control the devices at both ends.

[Problems to be solved by the invention]

In the conventional switching control method of the master device described above, arbitration is performed between the active device and the standby device, and therefore, in the construction of a highly reliable network by completely duplicating the loop,
When each of the two working / standby master devices controls the loop cable in which the working / standby is formed into one, four master devices are connected to one loop, and arbitration between the master devices is performed. There was a problem that became impossible.

SUMMARY OF THE INVENTION An object of the present invention is to provide a master device switching control method which solves the above-mentioned problems by taking a means for automatically using one of the master devices even when there are a plurality of master devices. is there.

[Means for solving the problem]

In the switching method of the master device according to the present invention, a loop network is constructed by serially connecting N devices in the same loop, each having a device code which is prioritized in advance,
When requesting the active (ACT) state by transmitting its own device code, when the device code having a higher priority is received, it is transmitted and transmitted as it is to the standby (SBY) state, while the same device code is transmitted. In a switching method of a master device having a plurality of master devices operating in an active (ACT) state upon reception, spare (SBY) status information for each master device in an N-bit code in a transmission frame format on the loop network. Wherein the master device transmits a received code as it is when the device function is stopped due to a failure, and transmits all N bits with code 0 as SBY status information when in the ACT state and SBY when in the SBY status. Transmitting means for calculating the logical sum of the position assigned to the N bits received as the state information as code 1 and transmitting the same, and receiving the data in the ACT state If the position assigned to itself in the SBY state information is code 1, it is determined that the ACT state request is permitted. If the position is code 0, the ACT state request is permitted when the received device code is lower in rank than its own device code. Determination means for determining that the position assigned to itself in the SBY state information received in the SBY state is code 1
ACT means for setting the ACT state.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.
FIG. 1 shows a transmission / reception unit of a master device when four master devices exist on a loop.

As shown in FIG. 1, the binary code switch 10 assigns active (ACT) state information and spare (SBY) state information to the receiving unit 20 and the transmitting unit 30 of each master device. Receiver 20
Has a comparator 21 and selectors 22 and 23, and the transmitting section 30 has selectors 31 and 33 and a decoder 32, respectively.

First, the transmission unit 30 will be described. The selector 31 receives the assigned device code from the binary code switch 10 when in the ACT state, and receives the received ACT state RA0.1 in the SBY state.
Are selected and transmitted as ACT information SA0.1. The decoder 32 outputs the code 1 to one bit position assigned among the received SBY information RS0 to RS3. Selector 33
Is a code 0 for all SBY information SS0 to 3 in the ACT state
And in the SBY state, the output of the decoder 32 and the received SBY
The logical OR with the information RS0-3 is selected, and the SBY information SS0 is selected.
３3.

The comparator 21 of the receiving unit 20 is connected to the binary code switch 10
And compares the assigned device code received from the ACT information RA0.1 with the received ACT information RA0.1, and determines and outputs the priority. The selector 22 extracts and outputs a bit at one assigned position of the SBY information RS0 to RS3 received by the device code received from the binary code switch 10. Selector 23 is AC
Selects the logical sum of the outputs of the selector 22 and the comparator 21 in the T state, and selects the output of the selector 22 in the SBY state.
Output as HK (judgment) signal.

FIG. 2 is a format diagram showing an example of a transmission frame on a loop connecting four master devices according to FIG. The transmission frame consists of ACT information A0 and A following the synchronization bit F.
1. It is composed of SBY information S0 to S3 and data D. In the master device, the transmission information is distinguished by adding a reception (R) and transmission (S) code.

FIG. 3 is an information formation diagram showing the relationship between FIG. 1 and FIG. In FIG. 3, the receiving unit 20 has ACT information RA0.
RA1 and SBY information RS0 to RS3 are received, and the transmission unit 30
Information SA0 / SA1 and SBY information SS0 to SS3 are transmitted. The receiving unit 20 and the transmitting unit 30 use the device code assigned to themselves as ACT information. Four codes 00, 01, 10, and 11 are assigned to the ACT information A0 and A1 of the four master devices, respectively. 4
Four master devices are allocated to each of the SBY information S0 to S3.

Now, ACT information 0 is assigned to each of the four master devices M0 to M3.
0.10.01.11 are assigned, SBY information S0 to S3 are respectively assigned, and the priority order of the ACT information is code 00> code 10> code 01>.
Reference numeral 11 (that is, master device M0>M1>M2> M3), and the connection order of the loops is set to master devices M0, M2, M1, and M3.
FIG. 7 to FIG. 7 will be described with reference to FIG. 1 to FIG.

FIG. 4 is a block connection diagram showing an information transmission / reception state of each of the master devices M0 to M3 when the master device M0 is in the ACT state. First, the master device M0 in the ACT state has its own device number 00.
Is ACT information 00 and all positions are set to code 0.
Send information 0000. The master device M2 receives the output of the master device M0 as an input, and in the SBY state, transfers and outputs the ACT state 00 as it is. The SBY information transmits a code 0010 obtained by adding a code 1 to the third position assigned to itself. Similarly, the master device M1
Is received from the master device M2 and transmitted to the master device M3.
The output of master device M3 is received by master device M0.

FIG. 5 is a block connection diagram showing an example of a state in which the master device M0 is disconnected due to a failure in the state of FIG. FIG. 5 (1) shows that the master device M0 disappears from the state of FIG. 3, and the output of the master device M3, ACT information 00 and SBY information 01
11 inputs directly to the master device M2. The master device M2 in the SBY state selects the code 1 at the third position of the received SBY information into the selector 2
The receiving unit 20 recognizes the signal as a CHK signal via 2 and the selector 23, and changes to the ACT state. Therefore, as shown in FIG. 5 (2), the master device M2 outputs the device code 01 as ACT information and outputs the SBY information of code 0000 to the master device M1. Since the master devices M1 and M3 are in the SBY state, they change the transmission information according to the change in the reception information, and are stabilized in the state of FIG. 5 (3).

FIG. 6 is a block diagram showing an example of a state in which the master device M0 recovers from the state of FIG. 5 (3) and joins again on the loop. In FIG. 5 (3), the master device M0 is SBY
When re-joining in the state, the master device M0 receives the output of the master device M3, the ACT information 01 and the SBY information 0101, so that the circuit of FIG. 1 transmits the ACT information 01 and the SBY information 1101,
This transmission information is received while the master device M2 is in the ACT state. Therefore, the master devices M1 and M3 remain unchanged.

Next, FIG. 7 shows that when the master device M0 in the ACT state in FIG. 4 has exited, and in FIG. 5 the next master device M2 has changed to the ACT state. FIG. 14 is a block connection diagram showing an example of a process until one master device M1 in an ACT state is set when information has made one cycle.

FIG. 7 (1) shows the output of the master device M3 immediately before the lost master device M0, and the ACT information 00 and the SBY information 0111 are the master devices M2 and M.
1. Pass through M3. Since the bit position of the assigned SBY information is code 1, each of the master devices M1 to M3 changes from the SBY state to the AC
Change to T state. Therefore, as shown in FIG. 7 (2), each master device sets its own device code in the ACT information and the code 0
000 is output as SBY information. Therefore, the received ACT information becomes the codes 11, 01, and 10 in the order of the master devices M2, M1, and M3, and when comparing with the device codes 01, 10, and 11 of the master devices M2, M1, and M3, respectively, the master device M3 Changes from the ACT state to the SBY state because of the inferiority, the output is set to ACT information 10 and SBY information 0001, and the state shown in FIG. Therefore, the master device M2
Receives the output of the master device M3, the ACT information 10 and the SBY information 0001, compares the ACT information 10 with its own device code 01 to determine its own inferiority, changes from the ACT state to the SBY state, and outputs FIG. 7 (4) shows the state as ACT information 10 and SBY information 0011.

FIG. 7 (5) shows that only the master device M1 has ACT information 10, SBY.
When the information 0011 is input, the ACT state is connected as the dominant state, indicating a stable state.

In this state, even if the highest-priority master device M0 is restored and connected, as in the description of FIG. 6, the current operation is maintained and there is no switching back. Therefore, there is no switchback control in the switching control of the master device, and the disturbance of the system can be minimized.

〔The invention's effect〕

As described above, in the switching control method of the master device of the present invention, each master device knows the presence or absence of the master device on the loop with the SBY information provided on the transmission frame format, and maintains the SBY state or transits to the ACT state. , Know the priorities on the loop with the prioritized ACT information A
By maintaining the CT state or transiting to the SBY state,
Since arbitration of switching control can be performed between a plurality of master devices, there is an effect that a highly reliable network can be constructed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a switching control system for a master device according to the present invention, FIG. 2 is a format diagram showing an example of a transmission frame existing on a loop according to FIG. 1, and FIG. FIG. 4 is an information formation diagram showing an example of transmission / reception information of the master device of the present invention. FIG. 4 is a block connection diagram showing an example of an information transmission / reception state when the master device M0 is in the ACT state.
FIG. 6 is a block connection diagram showing an example when the master device M0 comes out of the state shown in FIG. 4, FIG. 6 is a block connection diagram showing an example when the master device M0 is restored in the stable state shown in FIG. FIG. 7 shows the second state in which the master M0 in the ACT state is disconnected in FIG.
And FIG. 8 is a block diagram showing an example of the related art. 10 binary code switch, 20 receiver, 21 comparator, 22, 23, 31, 33 selector, 30 transmitter, 3
2 ... Decoder.

Claims (1)

(57) [Claims] 1. A loop network is constructed by serially connecting N units on the same loop, each having a device code which has been prioritized in advance, and transmitting its own device code to request an active (ACT) state. If a device code with a higher priority is received, the
In the switching mode of a master device having a plurality of master devices operating in the active (ACT) state when the same device code is received while receiving the same own device code, the transmission frame format on the loop network is N. Spare for each master device by bit code (SBY)
Transfer means for transferring the received code as it is when the function of the master device is stopped due to a failure; and when the master device is in the ACT state, all of the N bits are transmitted as the SBY state information with the code 0 and the master device is in the SBY state. Sometimes the position assigned to the N bits received as SBY state information is denoted by code 1.
A transmitting means for performing a logical sum as a transmission, and in the SBY state information received in the ACT state, if the position assigned to itself is code 1, it is determined that the ACT state request is permitted; Means for determining that an ACT state request is permitted when the received device code is lower than its own device code; and ACT state when the position assigned to itself in the SBY state information received in the SBY state is code 1. And a ACT means for switching the master device.