JPS6239465Y2 - - Google Patents

Description

[Detailed description of the invention] This invention allows only one of multiple devices to go online, and only when that online device goes offline or is disconnected, other spare devices can go online. This relates to a working standby switching circuit in which when any one of them goes online, the remaining standby devices are prohibited from going online.

For example, in information processing systems, it has recently become common practice to provide a console processor that controls the man-machine interface between an operator and the system. When viewed from the main body, the console processor was given a unique machine number, and it was common for only one console processor to be installed. However, in order to improve reliability, it is desirable to use multiple console processors. In that case, if two or more consoles are online at the same time, there is a risk of incorrect operation.
A system is required in which at most only one console is online, and furthermore, when a failure occurs in that online device, it is necessary to quickly disconnect that device and bring another device online.

This will be explained in detail below with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.
CPU is the main unit, U1 and U2 are console processors, SVP1 and SVP2 are the logic control circuit sections of the console processors, CONT1 and CONT2 are connection control sections, SW1 and SW2 are online switches, INH is the inhibit signal line, and CBUS is the common bus.

SVP1 and SVP2 are connected in parallel to the common bus CBUS. CONT1 and CONT2 are connected in series to the inhibit signal line INH. An embodiment of the CONT section is shown in FIG. In the figure, A and B are relays, a1 and a2 are make contacts of relay A, b1 is a make contact of relay B, and b2 is a break contact of relay B.

When INH from the rear stage side (right side in the figure) is present, relay B operates, contacts b1 are made, and INH is sent to the front stage side. Also, contact b2 is broken to disable SW and prohibit relay A from operating. When there is no INH from the downstream side, relay B does not operate and INH is not sent to the upstream side.
Therefore, the switch SW is enabled in all devices. If the SW of a certain device is closed, the relay A of that device operates, makes contact a1, sends INH to the previous stage side, and disables the previous stage side SW.
Contact a2 is also made to provide an activation signal to the SVP section to enable communication with the CBUS.

If SW is closed in a device at a later stage at this stage, relay A of the device at a later stage is operated, and therefore INH is applied to the device and the device is taken offline. In other words, the devices on the latter stage are given priority. Therefore, normally the latter device is used online, and when a failure occurs, the former device is brought online. Once the downstream equipment is restored, it can be restored by closing its SW.

As described above, the present invention has a simple connection control section.
Exclusive connection of multiple devices can be made by simply adding CONT, which is very effective in multiplexing console processors, etc.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a circuit diagram of one embodiment of the connection control section. In the figure, the CPU is the main body, U1 and U2 are the console processors, SVP1 and SVP2 are the logic circuit parts,
CONT1, CONT2 are connection control parts, SW1, SW
2 is an online switch, and A and B are relays.

Claims (1)

[Scope of utility model registration request] Switching between active and standby devices in which only one of multiple devices is used as the active device and the others are spares, and when the active device is disconnected or taken offline, only one of the backup devices automatically becomes the active device. In this case, the above-mentioned plurality of devices are connected in parallel to a common bus, and the inhibit signal line is connected in series to each device, and when each device receives an inhibit signal from the subsequent device, the break contact relay stops the device from going online. When there is no inhibit signal from the subsequent device, the break contact relay enables the device to go online, and when the device is online, A working standby switching circuit characterized in that an inhibit signal is sent to a preceding stage device by a make contact relay, so that only one device can be brought online at any time.