DE20020502U1 - Switching device - Google Patents

Description

Switching device

The invention relates to a switching device for switching electrical devices and systems to the power supply of the second line in the event of a power failure of the first line in energy supply systems having two power supply lines.

When operating certain electrical equipment and systems, such as electromedical equipment, operating rooms, air monitoring equipment, special production facilities, etc., a constant power supply on a supply line is required despite a power failure.

This is achieved by switching to the second line as a second safe power supply source if the power supply via the first line fails and by switching the power supply of the devices or systems back to the first line when the voltage on the first line returns.

The switching process to the second line takes place in the usual way immediately after a power failure and the length of the interruption is 0.5 seconds to 15 seconds.

The switchback to the first line occurs after the voltage on the returning network has been stable for a defined period of time and during this switchback there is again an interruption in the power supply of about 0.5 seconds.

These switching processes impair the functionality of the connected devices and systems in various ways, but must not result in a situation that endangers people or systems.

The failure of the first line and the necessary switching process and the associated voltage interruption cannot be predicted or influenced by the connected devices and systems.

The disadvantage in these cases is that in the case of connected devices and systems such as electromedical devices, the power failure caused by the switching process can interrupt measuring, work or therapy processes, for example X-ray examinations, other diagnoses and treatments such as laser beam treatments, artificial respiration, etc., and endanger people. After the power is returned, work processes can be repeated and ongoing examinations can be impaired.

The invention therefore has the object of eliminating the disadvantages mentioned above.

According to the invention, the object is achieved in that the switching device and the devices connected to it are equipped with microcontrollers and are connected to one another via a field bus and, when the mains voltage changes, the connected devices are informed of the impending switchover before switching to the second line or before switching back to the first line.

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or switchback is signaled and the switchback can be delayed by the connected devices via the fieldbus.

The delay times between warning and re-switching and the waiting time to delay the re-switching are adjustable and can be queried by the connected devices.

In a further embodiment of the invention, the switching device and its microcontroller can be coordinated in such a way that delay messages from the connected devices are only taken into account during the switchback time and, if the switchback time is exceeded, a switchback is initiated with simultaneous indication of the impending switchback.

Furthermore, the delay times of the connected electrical devices can be changed within a predefined time frame if necessary. 20

An embodiment of the invention is described in more detail below:

Figure 1 shows an inventive solution for the continuous power supply of electromedical devices

Figure 2 shows a flow diagram of the switching and switching back with the respective signal sequences and their information content.
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The invention minimizes the influence of electrical devices and systems that are operated via switching devices via a second line after the failure of the first line, warns them of an impending switching process and can adjust their working regime to the impending voltage failure caused by the switching and, depending on their current working regime, can delay the impending switchback to the first line in order to be able to complete a work step that is currently in progress.

The first line 1 supplies the electromedical devices 5 and 6 with the required operating voltage via the switching device 3 and outgoing lines 4.

If the mains voltage on the first line 1 fails, the switching device switches to the second line 2 and the connected electromedical devices 5 and 6 receive their operating voltage via the second line 2.

The switching device 3 and the electromedical devices 5 and 6 each have a microcontroller and are connected to each other via a field bus 7 as a communication link.

The microcontroller of the switching device is programmed in such a way that information corresponding to the following signal content is sent to the connected devices or systems:

Switchover is imminent
Switchback is imminent

Re-switching is imminent and cannot be delayed

whereas the microcontroller of the devices sends to the switching device 3 information with the signal content

- Delay switchback
gives away.

The delay times between warning and switching or warning and switching back as well as the waiting time for delaying the switching back can be set within a defined value range and queried via the electromedical devices.

If there is a deterioration in the network quality, which indicates an impending power failure, the microcontroller of the switching device 3 sends a defined warning signal to the connected electromedical devices 5 and 6 "Switching process is imminent".

This warns the connected devices of an impending switching process so that they can automatically adjust their own working regime to the impending short power failure.

As soon as the required operating voltage of the first line is reached again over a defined time, the switching device gives a signal in good time before switching back

•a ···*

a warning message "Return switchover imminent" to the connected electromedical devices 5 and 6.

Depending on the operating state, the connected devices 5 and 6, upon receipt of this information, send a "delay switchback" message to the switching device and simultaneously to all other connected devices if necessary in order to be able to properly terminate a transient state in the operating regime.

After receiving this information, the switching device 3 does not carry out a switchback, but after a predetermined waiting time, a warning message "Switchback imminent" is sent to the connected devices again.

In a further embodiment of the invention, when a large number of devices are connected to the switching device 3, the microcontroller only issues the messages "Delay switching back" during the switching back time.

taken into account and after the switchback time has elapsed the information "switchback is imminent and cannot be delayed" is given and only then is the switchback initiated.

As in the embodiment described above, the invention can also be applied to other electrical systems such as building automation, elevator control, etc., in which mobile and stationary devices and systems can be connected to a switching device via a communication connection and control processes are carried out with the aid of the switching device.

Claims (4)

1. Switching device for switching electrical devices and systems to the power supply of the second line in the event of a power failure of the first lines in energy supply systems which have two supply lines, characterized in that the switching device and the devices connected to it are equipped with microcontrollers and are connected to one another via a field bus and, if the mains voltage of the first line changes before switching to the second line or also when switching back to the first line, the connected devices are respectively signaled the impending switchover or switchback and the switchback can be delayed by the connected devices via the field bus. 2. Switching device according to claim 1, characterized in that the delay time between warning and switchback and the waiting time for delaying the switchback are adjustable and can be queried by the connected devices. 3. Switching device according to claims 1 and 2, characterized in that it takes delay messages into account only for a certain maximum switch-back time and, if the switch-back time is exceeded, carries out the impending switch-back and after prior indication of the same. 4. Switching device according to claims 1 and 2, characterized in that the delay times of the connected devices can be changed within a defined time range.