JPH07240259A - Table tap - Google Patents

Abstract

PURPOSE:To stop power supply to a specific equipment only when a table tap is applied to a system in which the specific equipment is shared with plural equipments if all power switches for the plural equipments with which the specific equipment is shared are off. CONSTITUTION:A receptacle 10 is provided for a power supply to a printer 50 which is shared with three personal computer mainframes 51, 52, 53 and receptacles 11, 12, 13 are provided for power supplies to three personal computer mainframes. Current monitors 21, 22, 23 detect currents and also output current detection signals S1, S2, S3 showing '0' or '1' depending on whether detected current values exceed threshold current values. A switch control 30 outputs to a switch 20 a control signal So showing logical sum or the logical product of the current detection signals S1, S2, S3. The switch 20 turns on or off a current to the receptacle 10 corresponding to the control signal So.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a table tap for supplying electric power from a single power plug to a plurality of devices constituting a single system.

[0002]

2. Description of the Related Art A conventional table tap of this type is disclosed in, for example, Japanese Patent Laid-Open No. 250250/1990. That is, as shown in FIG. 2, it has a plug 1, a plurality of outlets 2, 3, 4 and a current relay 5. Here, the coil 51 of the current relay 5 is connected in series to one specific outlet 2.
Further, the normally-open contacts 52 and 53 of the current relay 5 are connected in series to the other outlets 3 and 4, respectively.

For example, when the table tap is used in a personal computer system, the personal computer main body is connected to a specific outlet 2 and peripheral devices such as a display and a printer are connected to the outlets 3 and 4, respectively.
Then, if you turn on the power switch of the personal computer,
Current flows through the coil 51 of the current relay 5 and the contact 5
Since the terminals 2 and 53 are closed, electric power is supplied to the display and the printer connected to the outlets 3 and 4, respectively. Further, when the power switch of the personal computer main body is turned off, current does not flow through the coil 51 of the current relay 5 and the contacts 52 and 53 are opened, so that power is supplied to the displays and printers connected to the outlets 3 and 4. Is cut off.

In this way, in conjunction with the power switch ON / OFF of the device connected to one specific outlet,
By controlling the power supply to the devices connected to the other outlets, it is possible to prevent forgetting to turn off the power switch of each device connected to the other outlets and operation mistakes.

[0005]

The above-mentioned conventional table tap is interlocked with the power ON / OFF of the device connected to one specific outlet, and the power to the device connected to another outlet is also turned ON / OFF. You can do it. However, when used in a system in which a plurality of personal computer bodies share one printer, the printer must be kept operating when at least one of the plurality of personal computer bodies is operating. As shown, prepare the same number of table taps as the PC main unit, connect the PC main unit to one specific outlet of each table tap, and connect the power plugs of the printer in parallel to the outlets of each table tap. I have to keep it.

Therefore, when a conventional table tap is used in a system in which a plurality of devices share a specific device, it is necessary to use a plurality of table taps and a plurality of plugs for special wiring. However, there is a problem in that a short circuit or a burnout accident may occur due to a wiring mistake.

An object of the present invention is to provide a table tap effective when applied to a system in which a plurality of devices share a specific device.

[0008]

The table tap of the present invention includes one power plug for receiving power from an external power source,
M + n that receives the electric power from the power plug in parallel
(M is an integer greater than or equal to 1 and n is an integer greater than or equal to 2) outlets and m of these m + n outlets are respectively connected in series and energization is turned on / of according to a control signal.
F switch m units, and n of the m + n outlets are respectively connected in series to detect current, and current detection indicating whether or not the detected current value exceeds a threshold value. N current monitor units that output signals, respectively, and the m switch units that receive the current detection signals from the n current monitor units and that indicate the logical sum or logical product thereof as the control signal. And a switch control unit for outputting to.

[0009]

The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, showing a configuration in the case where three personal computer main bodies 51, 52 and 53 are applied to a personal computer system in which one printer 50 is shared. .

Here, the outlet 10 is for the power supply of the printer 50, and the outlets 11, 12, 13 are for the power supply of the three personal computer main bodies 51, 52, 53. Further, a switch unit 20 is connected in series to the outlet 10, and the outlets 11, 12, and 13 have current monitoring units 21,
22 and 23 are respectively connected in series.

The switch section 20 operates according to the control signal So to turn on / off the power supply to the outlet 10.
Further, the current monitoring units 21, 22, 23 detect the current, and compare the detected current value with the threshold current value and output current detection signals S1, S2, S3, respectively. The switch control unit 30 generates a control signal So according to the current detection signals S1, S2, S3 and controls the switch unit 20.

Next, the operation will be described.

The power plug 40 is plugged into an external power outlet, the power plug of the printer 50 is plugged into the outlet 10, and the power plugs of the three PCs 51, 52 and 53 are plugged into the outlets 11, 12 and 13, respectively. Put in. At this time, since the personal computer has a battery charging function or the like, current flows even if the power switches 61, 62, 63 are OFF, but the threshold currents of the current monitoring units 21, 22, 23 are adjusted so as not to respond to this. Set the value.

Thereafter, the power switch 60 of the printer 50
And the power switch 6 of the personal computers 51, 52, 53
Turning on 1, 62 and 63 respectively, the current monitoring unit 2
A predetermined current flows through the personal computer main bodies 51, 52, 53 via the terminals 1, 22, 23 and the outlets 11, 12, 13. The current monitoring units 21, 22, 23 detect this current,
Depending on whether or not the detected current value exceeds the threshold current value, the power switch O of the personal computer main body 51, 52, 53 is turned on.
N, OFF is detected and current detection signals S1, S2, S3 are sent out. In this case, the current detection signals S1, S2, S3
Is "0" when the detected current value is smaller than the threshold current value.
In addition, when the detected current value is equal to or more than the threshold current value, “1” is indicated.

The switch control unit 30 controls the current detection signal S
1, S2, S3 are respectively received and the signal which shows the logical sum is output as control signal So. That is, the control signal So is set to "0" only when the current detection signals S1, S2, S3 all indicate "0", and the current detection signals S1, S
When at least one of 2 and S3 indicates "1", the control signal So is set to "1". Therefore, the control signal So indicates "0" only when all the power switches of the personal computer main bodies 51, 52, 53 are OFF, and the personal computer main body 5
If at least one of the power switches 1, 52, 53 is ON, the control signal So indicates "1".

In the switch section 20, the control signal So is "0".
When it shows, it turns off, and when it shows "1," it turns on. That is, if at least one power switch of the personal computers 51, 52, 53 is turned on, the printer 50 is continuously energized,
Further, the power supply to the printer 50 is stopped only when all the power switches of the personal computer main bodies 51, 52 and 53 are OFF.

The current detection signals S1, S2, S3 output from the current monitoring units 21, 22, 23 indicate "1" when the detected current value is smaller than the threshold current value, and the detected current value is It may be set to indicate "0" when it is larger than the threshold current value. In this case, the switch control unit 30
In the above, the signal indicating the logical product of the current detection signals S1, S2, S3 is output as the control signal So, and
The switch unit 20 is turned off when the control signal So indicates “1” and turned on when the control signal So indicates “0”.

By the way, when there are a plurality of shared printers, it suffices to add an outlet to which the switch section is connected in series and control by the control signal So. Generally, when n (n is an integer of 2 or more) devices (for example, a personal computer body) use m (m is an integer of 1 or more) specific shared devices (for example, printers), m + n Outlets are provided, the switch units are connected in series to the m outlets respectively, and the current monitoring units are connected in series to the n outlets respectively, and the logical sum of the current detection signals from the current monitoring units is obtained. Alternatively, the switch unit may be turned on and off according to the logical product.

[0020]

As described above, according to the present invention, when applied to a system in which a plurality of devices use a specific shared device, the outlet for the shared device is energized and turned off.
F switch units are connected in series, and a current monitoring unit that detects whether or not a predetermined current is flowing and outputs a current detection signal is connected in series to an outlet for a plurality of devices that use a shared device. Power is supplied to the shared device only when all the power switches of the multiple devices that use the shared device are turned off by connecting each and controlling the switch part to turn on and off by the logical sum or logical product of the current detection signals. Since the power supply can be stopped, there is no need for special wiring using multiple table taps and multiple plugs as in the past, and troubles due to operation mistakes of the power switch of shared equipment and wasteful power consumption due to forgetting to turn off can be prevented. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of a conventional table tap.

FIG. 3 is a diagram showing a wire connection state when the conventional table tap shown in FIG. 2 is used in a system in which three personal computer bodies share one printer.

[Explanation of symbols]

 10, 11, 12, 13 Outlet 20 Switch section 21, 22, 23 Current monitoring section 30 Switch control section 40 Power plug So control signal S1, S2, S3 Current detection signal

Claims (1)

[Claims] 1. A power plug that receives power from an external power source, and m + n (m is an integer of 1 or more, and n is an integer of 2 or more) outlets that receive the power from the power plug in parallel, These m + n outlets are connected in series to m outlets to turn on electricity according to a control signal.
It is connected to n switches of N and OFF and n switches of the m + n outlets in series to detect current, and indicates whether or not the detected current value exceeds a threshold value. N current monitoring units that output current detection signals respectively, and signals that receive the current detection signals from the n current monitoring units and that indicate the logical sum or logical product thereof are the m control signals. A table tap, comprising: a switch control unit for outputting to a switch unit.